Dentinogenic responses after direct pulp capping of miniature swine teeth with Biodentine.

PubMed

Tziafa, Christina; Koliniotou-Koumpia, Eugenia; Papadimitriou, Serafim; Tziafas, Dimitrios

2014-12-01

The aim of this study was to evaluate pulpal responses after experimental direct pulp capping of mechanically exposed teeth with a new calcium silicate-based dentin replacement material. Thirty-four anterior and posterior teeth of 3 miniature swine were used. Class V or I cavities were prepared on the buccal or occlusal surfaces, respectively. Pulpal exposures were further performed using a round carbide bur 0.8 mm in diameter. Exposures were treated with white MTA Angelus (Angelus, Londrina, PR, Brazil) or Biodentine (Septodont, Saint Maur des Fosses, France), and the cavities were further restored with Biodentine. The pulpal tissue responses were histologically assessed at postoperative periods of 3 and 8 weeks. Data were statistically analyzed using the Kruskal Wallis and the Mann-Whitney U tests. Inflammatory infiltration or pulp tissue necrosis was not found in any of the specimens. All teeth showed mineralized matrix formation in the form of a complete hard tissue bridge composed of osteodentin or osteodentin followed by a discontinuous or continuous reparative dentin zone. A significantly higher thickness of the hard tissue bridge was found in the group of teeth treated with Biodentine at both 3 and 8 weeks. A number of teeth, which were under root development at the onset of the experimental procedures, exhibited ectopic pulp calcification. The application of both calcium silicate-based materials in direct contact with the mechanically exposed pulp of healthy miniature swine teeth led to pulp repair with complete hard tissue bridge formation. The thickness of hard tissue bridges was significantly higher after pulp capping with Biodentine. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Clinical and Radiographic Evaluation of Allium sativum Oil as a New Medicament for Vital Pulp Treatment of Primary Teeth

PubMed Central

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2014-01-01

Background: The objective of this study was to compare between the clinical and radiographic effects of Allium sativum oil and those of formocresol in vital pulpotomy in primary teeth. Materials and Methods: A total of 20 children age ranged from 4 to 8 years were included in the study. In every one of those children, the primary molars indicated for pulpotomy. Pulpotomy procedure was performed, and the radicular pulp tissue of one molar capped with A. sativum oil in a cotton pellet, whereas the other molar capped with formocresol, the teeth evaluated clinically and radiographically before and after 6 months, using standard clinical and radiographical criteria. Statistically, these results revealed no significant difference between the radiographic findings of vital pulpotomy in primary molars with the two medicaments was found. Results: A. sativum oil offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. Vital pulpotomy with allium sativa oil was given raise 90% success rate while that with formocresol was 85%. Conclusion: A. sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. PMID:25628480

An in vivo model for evaluating the response of pulp to various biomaterials.

PubMed

McClugage, S G; Holmstedt, J O; Malloy, R B

1980-09-01

An in vivo model has been designed to study the acute response of exposed or unexposed dental pulp to the topical application of various biomaterials. This model permits sequential microscopic observations of the microvascular system of dental pulp before and after application of pulp capping agents, cementing agents, or cavity liners. The use of this experimental model provides useful information related to the tolerability of dental pulp to various biomaterials used in dentistry. Furthermore, this model serves as a useful supplement to more traditional long term methods for evaluating the biocompatability of dental materials.

Effect of Propolis on Dentin Regeneration and the Potential Role of Dental Pulp Stem Cell in Guinea Pigs

PubMed Central

Ahangari, Zohreh; Naseri, Mandana; Jalili, Maryam; Mansouri, Yasaman; Mashhadiabbas, Fatemeh; Torkaman, Anahita

2012-01-01

Objective: Evaluation of the effect of Propolis as a bioactive material on quality of dentin and presence of dental pulp stem cells. Materials and Methods: For conducting this experimental split-mouth study,a total of 48 maxillary and mandibular incisors of male guinea pigs were randomly divided into an experimental Propolis group and a control calcium hydroxide group. Cutting the crowns and using Propolis or calcium hydroxide to cap the pulp, all of the cavities were sealed. Sections of the teeth were obtained after sacrificing 4 guinea pigs from each group on the 10th, 15th and 30th day. After they had been stained by hematoxylin and eosin (H&E), specimens underwent a histological evaluation under a light microscope for identification of the presence of odontoblast-like cells, pulp vitality, congestion, inflammation of the pulp and the presence of remnants of the material used. The immunohistochemistry (IHC) method using CD29 and CD146 was performed to evaluate the presence of stem cells and the results were statistically evaluated by Kruskal-Wallis, Chi Square and Fisher tests. Results: In H&E stained specimens, there was no difference between the two groups in the presence of odontoblast-like cells, pulp vitality, congestion, inflammation of the pulp and the presence of remnants of used material(p>0.05). There was a significant difference between the quality of regenerative dentin on the 15th and 30th days (p<0.05): all of the Propolis cases presented tubular dentin while 14% of the calcium hydroxide cases produced porous dentin. There was no significant difference between Propolis and calcium hydroxide in stimulation of dental pulp stem cells (DPSCs). Conclusion: This study which is the first one that documented the stimulation of stem cells by Propolis, provides evidence that this material has advantages over calcium hydroxide as a capping agent in vital pulp therapy. In addition to producing no pulpal inflammation, infection or necrosis this material induces the production of high quality tubular dentin. PMID:23508294

[Vital pulp therapy of damaged dental pulp].

PubMed

Xuedong, Zhou; Dingming, Huang; Jianguo, Liu; Zhengwei, Huang; Xin, Wei; Deqin, Yang; Jin, Zhao; Liming, Chen; Lin, Zhu; Yanhong, Li; Jiyao, Li

2017-08-01

The development of an expert consensus on vital pulp therapy can provide practical guidance for the improvement of pulp damage care in China. Dental pulp disease is a major type of illness that adversely affects human oral health. Pulp capping and pulpotomy are currently the main methods for vital pulp therapy. Along with the development of minimal invasion cosmetic dentistry, using different treatment technologies and materials reasonably, preserving healthy tooth tissue, and extending tooth save time have become urgent problems that call for immediate solution in dental clinics. This paper summarizes the experiences and knowledge of endodontic experts. We develop a clinical path of vital pulp therapy for clinical work by utilizing the nature, approach, and degree of pulp damage as references, defense and self-repairing ability of pulp as guidance, and modern technologies of diagnosis and treatment as means.

Effects of pulpotomy using mineral trioxide aggregate on prostaglandin transporter and receptors in rat molars.

PubMed

Ohkura, Naoto; Edanami, Naoki; Takeuchi, Ryosuke; Tohma, Aiko; Ohkura, Mariko; Yoshiba, Nagako; Yoshiba, Kunihiko; Ida-Yonemochi, Hiroko; Ohshima, Hayato; Okiji, Takashi; Noiri, Yuichiro

2017-07-31

Mineral trioxide aggregate (MTA) is a commonly used dental pulp-capping material with known effects in promoting reparative dentinogenesis. However, the mechanism by which MTA induces dentine repair remains unclear. The aim of the present study was to investigate the role of prostaglandin E 2 (PGE 2 ) in dentine repair by examining the localisation and mRNA expression levels of its transporter (Pgt) and two of its receptors (Ep2 and Ep4) in a rat model of pulpotomy with MTA capping. Ep2 expression was detected in odontoblasts, endothelial cells, and nerve fibres in normal and pulpotomised tissues, whereas Pgt and Ep4 were immunolocalised only in the odontoblasts. Moreover, mRNA expression of Slco2a1 (encoding Pgt), Ptger2 (encoding Ep2), and Ptger4 (encoding Ep4) was significantly upregulated in pulpotomised dental pulp and trigeminal ganglia after MTA capping. Our results provide insights into the functions of PGE 2 via Pgt and Ep receptors in the healing dentine/pulp complex and may be helpful in developing new therapeutic targets for dental disease.

Nano-hydroxyapatite and calcium-enriched mixture for pulp capping of sound primary teeth: a randomized clinical trial.

PubMed

Haghgoo, Roza; Asgary, Saeed; Mashhadi Abbas, Fatemeh; Montazeri Hedeshi, Roshanak

2015-01-01

Nano-hydroxyapatite (NHA) has been used for regeneration of osseous defects. Calcium-enriched mixture (CEM) cement is also used for various dental treatments. This trial compared the efficacy of NHA and CEM cement for direct pulp capping (DPC) of sound primary teeth. In this randomized clinical trial with split-mouth design, after attaining informed consent, 20 sound primary canines scheduled for orthodontic extraction, were selected. After mechanical pulp exposure, the exposed site was capped with either NHA or CEM cement and then immediately restored with glass-ionomer and resin composite. The teeth were extracted after two months and examined histologically. Parameters of hard tissue bridge (HTB) formation, its type and quality as well as pulpal inflammation scores were compared between the two experimental groups. The data were analyzed using the Mann Whitney U and Fisher's exact test. The level of significance was set at 0.001. All CEM specimens showed inflammation score of 0 (less than 10%). However, in NHA group, inflammation scores of 0 (less than 10%), 1 (10%-30%) and 2 (30%-50%) were observed in 2 (20%), 4 (40%) and 4 (40%) specimens, respectively (P<0.001). HTB was formed in all CEM specimens while it was developed in 2 specimens of NHA (20%; P<0.001). All CEM specimens showed normal pulp; only two cases in NHA group (20%) demonstrated uninflamed normal pulp. CEM cement was superior to NHA as a DPC agent in terms of HTB formation and pulp inflammation scores. It is a suitable material for the DPC of primary teeth.

Mesenchymal stem cells promote hard-tissue repair after direct pulp capping.

PubMed

Obeid, Maram; Saber, Shehab El Din Mohamed; Ismael, Alaa El Din; Hassanien, Ehab

2013-05-01

The aim of this study was to investigate the potential of autologous mesenchymal bone marrow stem cells (BMSCs) to promote hard-tissue formation after direct pulp capping procedures. Bone marrow was aspirated from the iliac crest of healthy dogs of nonspecific race. Mononuclear cells were obtained using the Histopaque (Sigma-Aldrich, St Louis, MO) protocol and cultured for 21 days. Direct pulp capping procedures were performed in posterior teeth, and then mineral trioxide aggregate (MTA), hydroxyapatite/tricalcium phosphate, or BMSCs were used as direct pulp capping agents. After 3 months, animals were sacrificed, and jaw segments were processed for radiographic examination using cone-beam computed tomography scanning and histologic examination to assess the formation of a hard-tissue barrier according to a scoring system. The longitudinal and cross-sectional radiophotographs and histologic sections confirmed the formation of an evident calcific barrier after direct pulp capping with MTA and BMSCs. Statistical analysis of the scores given for radiographic and histologic calcific bridge formation showed that both MTA and BMSCs had a comparable tendency to produce a hard-tissue barrier that was significantly higher than hydroxyapatite tricalcium phosphate (P < .05). Autologous mesenchymal BMSCs were able to promote hard-tissue formation after direct pulp capping procedures. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

[Confusion and solution for vital pulp therapy].

PubMed

Dingming, Huang; Qian, Lu; Qian, Liao; Ling, Ye; Xuedong, Zhou

2017-06-01

Dental pulp tissue plays a role in forming dentin, providing nutrition, conducting pain, and generating protective responses to environmental stimuli. Bacterial infection is the main cause of pulp disease, where histopathological changes are the histological basis for determining the choice of treatment and the evaluation of therapeutic effect. Thus, particular attention should be given to eliminate infection, as well as preserve and maintain pulpal health in teeth that show reversible or limited pulpal injuries. Vital pulp therapy, especially its indications and prognostic factors, has been a research hotspot that often causes confusion among clinicians. In this paper, we briefly introduce the confusion and solution for vital pulp therapy in terms of indications, pulp condition assessment, infection elimination, and capping material selection. In addition, we develop a clinical pathway and an operation normalization of vital pulp therapy to better perform the therapy.

Histological Effects of Enamel Matrix Derivative on Exposed Dental Pulp.

PubMed

Bajić, Marijana Popović; Danilović, Vesna; Prokić, Branislav; Prokić, Bogomir Bolka; Manojlović, Milica; Živković, Slavoljub

2015-01-01

Direct pulp capping procedure is a therapeutic application of a drug on exposed tooth pulp in order to ensure the closure of the pulp chamber and to allow the healing process to take place. The aim of this study was to examine the histological effects of Emdogain® on exposed tooth pulp of a Vietnamese pig (Sus scrofa verus). The study comprised 20 teeth of a Vietnamese pig. After class V preparation on the buccal surfaces of incisors, canines and first premolars, pulp was exposed. In the experimental group, the perforations were capped with Emdogain® (Straumann, Basel, Switzerland), while in the control group pulp capping was performed with MTA® (Dentsply Tulsa Dental, Johnson City, TN, USA). All cavities were restored with glass-ionomer cement (GC Fuji VIII, GC Corporation, Tokyo, Japan). The observational period was 28 days, after which the animal was sacrificed and histological preparations were made. A light microscope was used to analyze dentin bridge formation, tissue reorganization and inflammation, and the presence of bacteria in the pulp. The formation of dentin bridge was observed in the experimental and control groups. Inflammation of the pulp was mild to moderate in both groups. Angiogenesis and many odontoblast-like cells, responsible for dentin bridge formation, were observed. Necrosis was not observed in any case, nor were bacteria present in the pulp. Histological analysis indicated a favorable therapeutic effect of Emdogain® Gel in direct pulp capping of Vietnamese pigs. Pulp reaction was similar to that of MTA®.

Vital Pulp Therapies in Clinical Practice: Findings from a Survey with Dentist in Southern Brazil.

PubMed

Chisini, Luiz Alexandre; Conde, Marcus Cristian Muniz; Correa, Marcos Britto; Dantas, Raquel Venâncio Fernandes; Silva, Adriana Fernandes; Pappen, Fernanda Geraldes; Demarco, Flávio Fernando

2015-01-01

Studies based on dentists' clinical practice possess vital relevance to understand factors leading the clinicians to choose by a specific technique over another. This study investigated which clinical conduct therapies are adopted by dentists in front of deep caries. Was evaluated how the place of work, post-graduate training and years since complete graduation influenced their decisions. A cross-sectional study was performed using a self-applied questionnaire with dentists (n=276) in Southern Brazil. Information regarding post-graduation training (specialization, master's or PhD), clinical experience (years since completing graduation) and place of work were investigated. The information regarding pulp vital therapies (materials for direct pulp capping; techniques for caries removal in deep cavities and strategies for indirect pulp capping) were collected by specific questions. Data were submitted to descriptive analysis and Exact Fischer Test. Response rate was 68% (187). The majority of dentists selected the calcium hydroxide (CH) as first material for direct (86.3%) and indirect (80.3%) pulp protection. Partial caries removal was reported by 61.9% of dentists. Less experienced clinical dentists choose partial caries removal more frequently (p=0.009), if compared with dentists graduated 10 years and up ago. The use of MTA was more common among professionals working at academic environment. Besides, MTA was not mentioned by professionals working exclusively in the public health service (p=0.003). In conclusion, the time since graduation influenced the clinical conduct related to caries removal. The choice of liner materials was influenced by dentists' workplace.

Clinical and Radiographic Evaluation of Allium sativum Oil as a New Medicament for Vital Pulp Treatment of Primary Teeth.

PubMed

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2014-01-01

The objective of this study was to compare between the clinical and radiographic effects of Allium sativum oil and those of formocresol in vital pulpotomy in primary teeth. A total of 20 children age ranged from 4 to 8 years were included in the study. In every one of those children, the primary molars indicated for pulpotomy. Pulpotomy procedure was performed, and the radicular pulp tissue of one molar capped with A. sativum oil in a cotton pellet, whereas the other molar capped with formocresol, the teeth evaluated clinically and radiographically before and after 6 months, using standard clinical and radiographical criteria. Statistically, these results revealed no significant difference between the radiographic findings of vital pulpotomy in primary molars with the two medicaments was found. A. sativum oil offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. Vital pulpotomy with allium sativa oil was given raise 90% success rate while that with formocresol was 85%. A. sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning.

In vitro antibacterial activity of a novel resin-based pulp capping material containing the quaternary ammonium salt MAE-DB and Portland cement.

PubMed

Yang, Yanwei; Huang, Li; Dong, Yan; Zhang, Hongchen; Zhou, Wei; Ban, Jinghao; Wei, Jingjing; Liu, Yan; Gao, Jing; Chen, Jihua

2014-01-01

Vital pulp preservation in the treatment of deep caries is challenging due to bacterial infection. The objectives of this study were to synthesize a novel, light-cured composite material containing bioactive calcium-silicate (Portland cement, PC) and the antimicrobial quaternary ammonium salt monomer 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB) and to evaluate its effects on Streptococcus mutans growth in vitro. The experimental material was prepared from a 2 : 1 ratio of PC mixed with a resin of 2-hydroxyethylmethacrylate, bisphenol glycerolate dimethacrylate, and triethylene glycol dimethacrylate (4 : 3 : 1) containing 5 wt% MAE-DB. Cured resin containing 5% MAE-DB without PC served as the positive control material, and resin without MAE-DB or PC served as the negative control material. Mineral trioxide aggregate (MTA) and calcium hydroxide (Dycal) served as commercial controls. S. mutans biofilm formation on material surfaces and growth in the culture medium were tested according to colony-forming units (CFUs) and metabolic activity after 24 h incubation over freshly prepared samples or samples aged in water for 6 months. Biofilm formation was also assessed by Live/Dead staining and scanning electron microscopy. S. mutans biofilm formation on the experimental material was significantly inhibited, with CFU counts, metabolic activity, viability staining, and morphology similar to those of biofilms on the positive control material. None of the materials affected bacterial growth in solution. Contact-inhibition of biofilm formation was retained by the aged experimental material. Significant biofilm formation was observed on MTA and Dycal. The synthesized material containing HEMA-BisGMA-TEGDMA resin with MAE-DB as the antimicrobial agent and PC to support mineralized tissue formation inhibited S. mutans biofilm formation even after aging in water for 6 months, but had no inhibitory effect on bacteria in solution. Therefore, this material shows promise as a pulp capping material for vital pulp preservation in the treatment of deep caries.

Comparison of in vivo dental pulp responses to capping with iRoot BP Plus and mineral trioxide aggregate.

PubMed

Shi, S; Bao, Z F; Liu, Y; Zhang, D D; Chen, X; Jiang, L M; Zhong, M

2016-02-01

To compare dental pulp responses to capping with iRoot BP Plus and mineral trioxide aggregate (MTA) in dogs. Pulps in 36 incisors of three 8-month-old beagle dogs were mechanically exposed and assigned to two experimental groups (iRoot BP Plus group and MTA group, n = 15 per group) and one control group (n = 6). Direct pulp capping was performed using either iRoot BP Plus or MTA. The animals were sacrificed 3 months later. Histological sections were stained with haematoxylin and eosin and categorized using a histologic scoring system. Statistical analysis was performed using the Mann-Whitney U-test, with the significance set at 0.05. The majority of specimens in both experimental groups were associated with complete calcified bridge formation and the absence of pulpal inflammation. There was no significant difference in pulp response to iRoot BP Plus or MTA after 3 months (P > 0.05). iRoot BP Plus and MTA had similar favourable results when used as pulp-capping agents. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Dentine sialoprotein and collagen I expression after experimental pulp capping in humans using emdogain gel.

PubMed

Fransson, H; Petersson, K; Davies, J R

2011-03-01

To characterize the hard tissue formed in human teeth experimentally pulp capped either with calcium hydroxide or with Emdogain Gel (Biora AB, Malmö, Sweden) - a derivative of enamel matrix (EMD), using two markers for dentine; dentine sialoprotein (DSP) and type 1 collagen (Col I). Affinity-purified rabbit anti-Col I and anti-DSP polyclonal antibodies were used to stain histological sections from nine pairs of contra-lateral premolars that had been experimentally pulp amputated and randomly capped with EMDgel or calcium hydroxide. Twelve weeks after the teeth had been pulp capped, they were extracted, fixed, demineralized and serially sectioned prior to immunohistochemical staining. In the calcium hydroxide treated teeth DSP was seen in the new hard tissue which formed a bridge. DSP was also seen in the newly formed hard tissue in the EMDgel-treated teeth. Proliferated pulp tissue partly filled the space initially occupied by EMDgel and DSP-stained hard tissue was observed alongside exposed dentine surfaces as well as in isolated masses within the proliferated pulp tissue, although the new hard tissue did not cover the pulp exposure. DSP staining was also seen in the cells lining the hard tissue in both groups. Col I staining was seen in the newly formed hard tissue in both groups. The new hard tissue formed after pulp capping with EMDgel or calcium hydroxide contained DSP and Col I, considered to be markers for dentine. Thus, the newly formed hard tissue can be characterized as dentine rather than unspecific hard tissue. © 2010 International Endodontic Journal.

Direct pulp capping in primary molars using a resin-modified Portland cement-based material (TheraCal) compared to MTA with 12-month follow-up: a randomised clinical trial.

PubMed

Erfanparast, L; Iranparvar, P; Vafaei, A

2018-05-16

This study was to compare the success of resin-modified Portland cement-based material (TheraCal) with MTA in direct pulp capping (DPC) of primary molars. Symmetrical bilateral primary molars (92) from 46 healthy subjects aged 5-7 years were included in this split-mouth randomised clinical trial. DPC for small non-contaminated pulp exposures using either TheraCal or MTA were randomly performed in symmetrical molars. Thereafter, teeth were restored with amalgam. Clinical and radiographic evaluations were performed at 6 and 12 month follow-ups. Data were analysed using Chi square test at a significance level of 0.05. At the final follow-up session 74 teeth were available. After 12 months, the overall success rates for MTA and TheraCal were 94.5 and 91.8%, respectively. The difference between outcomes of the two groups was not statistically significant (P > 0.05). Within the limitations of the current study, radiographic and clinical findings revealed that TheraCal exhibited a comparable outcome to MTA in DPC of primary molars after 12 months.

Outcomes of direct pulp capping: interrogating an insurance database.

PubMed

Raedel, M; Hartmann, A; Bohm, S; Konstantinidis, I; Priess, H W; Walter, M H

2016-11-01

To evaluate the effectiveness of direct pulp capping under general practice conditions. It was hypothesized that direct pulp capping is an effective procedure in the majority of cases and prevents the need for root canal treatment or extraction. Claims data were collected from the digital database of a major German national health insurance company. Only patients who had been insurance members for the entire 3 year period 2010 to 2012 were eligible. Kaplan-Meier survival analyses were conducted for all teeth with direct pulp capping. Success was defined as not undergoing root canal treatment. Survival was defined as not undergoing extraction. Differences between survival functions were tested with the log rank test. A total of 148 312 teeth were included. The overall success rate was 71.6% at 3 years. The overall survival rate was 95.9% at 3 years. The success rates for single-rooted teeth (71.8%) and multirooted teeth (71.5%) were similar although significantly different (P < 0.001). Best 3-year success rates were found at low (79.7%; <18 years.) and very high age (81.8%; >85 years.). After direct pulp capping, more than two-thirds of the affected teeth did not undergo root canal treatment within 3 years. Although this study has the typical limits of a claims data analysis, it can be concluded that direct pulp capping is an effective intervention to avoid root canal treatment and extraction in a general practice setting. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Facile synthesis and characterization of novel rapid-setting spherical sub-micron bioactive glasses cements and their biocompatibility in vitro.

PubMed

Li, Yuli; Liang, Qiming; Lin, Cai; Li, Xian; Chen, Xiaofeng; Hu, Qing

2017-06-01

Dental pulp vitality is extremely important for the tooth viability, since it provides nutrition and forms the dentin. Bioactive glasses (BGs) may be promising materials for pulp repair due to their excellent abilities of rapidly bonding to bone and stimulating new bone growth. However, the unsatisfied handling property, low plasticity, and poor rapid-setting property of traditional BGs limit its application in vital pulp therapy. Spherical bioactive glasses (SBGs) exhibited higher osteogenesis and odontogenic differentiation than irregular BGs. This study focuses on the application of SBGs with rapid setting property for dental pulp repair. Here, SBGs with various compositions were successfully synthesized by a sol-gel process using dodecylamine (DDA) served as both a catalyst and a template. The maximum content of CaO in SBGs was about 15%. The non-bridge oxygen amounts of the SiO network and the apatite-forming ability increased with the content proportion of CaO and P 2 O 5 . Bioactive glass pulp capping materials (BGPCMs) were prepared by mixing the SBGs powders and the phosphate buffer solution (PBS). The K 3 CaH(PO 4 ) 2 and hydroxyapatite (HA) formed between SBGs particles as soon as they were mixed with PBS solution. The compressive strengths of fully set BCPCM-2 molded were measured to be 31.76±1.9577MPa after setting for 24h. The K 3 CaH(PO 4 ) 2 and the low crystallinity HA phases at the initial stage of solidification transformed to crystalline HA for 3days, and the compressive strength was still higher than 10MPa. Additionally, SBG-2 with a designed molar composition of 35% SiO 2 , 55% CaO and 10% P 2 O 5 more promoted dental pulp cell proliferation, and could be potential pulp capping applications. Copyright © 2017. Published by Elsevier B.V.

Outcomes of different vital pulp therapy techniques on symptomatic permanent teeth: a case series.

PubMed

Asgary, Saeed; Fazlyab, Mahta; Sabbagh, Sedigheh; Eghbal, Mohammad Jafar

2014-01-01

In modern endodontics, vital pulp therapy (VPT) has been considered an ultra-conservative treatment modality. Based on the level of pulp preservation, VPT includes stepwise excavation, indirect pulp capping (IDPC), direct pulp capping (DPC), miniature pulpotomy (MP), partial/Cvek pulpotomy and coronal/complete pulpotomy (CP). The present article reviews the treatment outcomes of 94 permanent teeth with irreversible pulpitis treated with either IDPC (n=28), DPC (n=28), MP (n=29) or CP (n=9) using calcium-enriched mixture (CEM) cement. After a mean follow-up time of 12.3 months, 93 treated teeth were radiographic/clinically successful; only one radiographic failure was observed in the DPC group.

Outcomes of Different Vital Pulp Therapy Techniques on Symptomatic Permanent Teeth: A Case Series

PubMed Central

Asgary, Saeed; Fazlyab, Mahta; Sabbagh, Sedigheh; Eghbal, Mohammad Jafar

2014-01-01

In modern endodontics, vital pulp therapy (VPT) has been considered an ultra-conservative treatment modality. Based on the level of pulp preservation, VPT includes stepwise excavation, indirect pulp capping (IDPC), direct pulp capping (DPC), miniature pulpotomy (MP), partial/Cvek pulpotomy and coronal/complete pulpotomy (CP). The present article reviews the treatment outcomes of 94 permanent teeth with irreversible pulpitis treated with either IDPC (n=28), DPC (n=28), MP (n=29) or CP (n=9) using calcium-enriched mixture (CEM) cement. After a mean follow-up time of 12.3 months, 93 treated teeth were radiographic/clinically successful; only one radiographic failure was observed in the DPC group. PMID:25386213

Formocresol versus calcium hydroxide direct pulp capping of human primary molars: two year follow-up.

PubMed

Aminabadi, Naser Asl; Farahani, Ramin Mostofi Zadeh; Oskouei, Sina Ghertasi

2010-01-01

Clinical and radiographic evaluation of the premedicated direct pulp capping using formocresol (PDC) versus conventional direct pulp capping using calcium hydroxide (CDC) in human carious primary molars. A total of 120 vital primary molars with pinpoint exposure during caries removal in 84 patients aged 4-5 years were selected. In the PDC group (n = 60), 20% Buckley's formocresol solution, and in the CDC group (n = 60), calcium hydroxide powder were applied to the exposure sites followed by placement of zinc oxide-eugenol base. Teeth were restored with preformed stainless steel crowns. Clinical and radiographic evaluations of the treatment outcomes were performed at regular intervals of 6 and 12 months, respectively, for two years post-operatively. The prevalence of spontaneous pain, sensitivity on percussion, and fistula were significantly higher in the CDC group compared to the PDC group (P < 0.05). The number of teeth exhibiting periapical/furcal radiolucency or external/internal root resorption was also higher in the CDC group (P < 0.05). The clinical success rate of the PDC was 90% compared to the 61.7% of the CDC (P < 0.05). The radiographic success rates of the PDC and CDC groups were 85% and 53.3%, respectively (P < 0.05). It seems formocresol premedicated direct pulp capping could safely be used as a substitute for conventional direct pulp capping.

USE OF COMPOSITE MATERIALS AS A COMPONENT OF TUSK FRACTURE MANAGEMENT IN AN ASIAN ELEPHANT (ELEPHAS MAXIMUS) AND AN AFRICAN ELEPHANT (LOXODONTA AFRICANA).

PubMed

Sim, Richard R; Stringer, Elizabeth; Donovan, Dennis; Chappell, Rachael; Flora, Pat; Hall, Jon; Pillay, Selvum; Willis, Benjamin G; McCain, Stephanie

2017-09-01

Tusk fractures in Asian (Elephas maximus) and African elephants (Loxodonta africana) can result in damage to the distal end or to longitudinal cracks, potentially progressing to pulpitis. With pulp exposure, endodontic therapy is the treatment of choice, but conservative therapy has sufficed for some elephants. This manuscript describes the use of composite materials as a component of tusk fracture management. A 7-yr-old male Asian elephant fractured the distal end of both tusks with pulp exposure in one. Capping of each tusk with a Kevlar/fiberglass composite prevented further damage, and a modification allowed care of the exposed pulp tissue. A 34-yr-old male African elephant with a longitudinal crack received a carbon fiber/fiberglass composite circumferential wrap to potentially stabilize the crack. Compression of the crack was achieved, but follow-up was truncated due to bacterial pulpitis. Both cases show that composite material allows for lightweight, durable management of tusk fractures with continued radiographic monitoring.

Incomplete caries removal and indirect pulp capping in primary molars: a randomized controlled trial.

PubMed

Bressani, Ana Eliza Lemes; Mariath, Adriela Azevedo Souza; Haas, Alex Nogueira; Garcia-Godoy, Franklin; de Araujo, Fernando Borba

2013-08-01

To compare the effect of incomplete caries removal (ICR) and indirect pulp capping (IPC) with calcium hydroxide (CH) or an inert material (wax) on color, consistency and contamination of the remaining dentin of primary molars. This double-blind, parallel-design, randomized controlled trial included 30 children presenting one primary molar with deep caries lesion. Children were randomly assigned after ICR to receive IPC with CH or wax. All teeth were then restored with resin composite. Baseline dentin color and consistency were evaluated after ICR, and dentin samples were collected for contamination analyses using scanning electron microscopy. After 3 months, restorations were removed and the three parameters were re-evaluated. In both groups, dentin became significantly darker after 3 months. No cases of yellow dentin were observed after 3 months with CH compared to 33.3% of the wax cases (P < 0.05). A statistically significant difference over time was observed only for CH regarding consistency. CH stimulated a dentin hardening process in a statistically higher number of cases than wax (86.7% vs. 33.3%; P = 0.008). Contamination changed significantly over time in CH and wax without significant difference between groups. It was concluded that CH and wax arrested the carious process of the remaining carious dentin after indirect pulp capping, but CH showed superior dentin color and consistency after 3 months.

Efficacy of Erbium, Chromium-doped:Yttrium, Scandium, Gallium, and Garnet Laser Irradiation Combined with Resin-based Tricalcium Silicate and Calcium Hydroxide on Direct Pulp Capping: A Randomized Clinical Trial.

PubMed

Cengiz, Esra; Yilmaz, Hasan Guney

2016-03-01

The purpose of this randomized clinical study was to evaluate the efficiency of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation combined with a resin-based tricalcium silicate material and calcium hydroxide in direct pulp capping for a 6-month follow-up period. A total of 60 teeth of 60 patients between the ages of 18 and 41 years were recruited for this study. Sixty permanent vital teeth without symptoms and radiographic changes were randomly assigned to the following 4 groups (n = 15): Gr CH, the exposed area was sealed with calcium hydroxide (CH) paste; Gr laser CH, the treated area was sealed with CH paste after Er,Cr:YSGG laser irradiation at an energy level of 0.5 W without water and with 45% air; Gr TheraCal, TheraCal LC (Bisco, Schaumburg, IL) was applied directly to the exposed pulp; and Gr Laser TheraCal, TheraCal LC was applied after irradiation with an Er,Cr:YSGG laser. At the 1-week and 1-, 3-, and 6-month recall examinations, the loss of vitality, spontaneous pain, reactions to thermal stimuli and percussion, and radiographic changes were considered as failure. The success rates in the CH and TheraCal groups were 73.3% and 66.6%, respectively. These rates did not reveal any significant difference. In both laser groups, success rates were 100%. The Er,Cr:YSGG laser-irradiated TheraCal and Er,Cr:YSGG laser-irradiated CH groups showed statistically higher success rates than the TheraCal and CH groups, respectively. Er,Cr:YSGG laser irradiation at 0.5 W without water combined with pulp capping agents can be recommended for direct pulp therapy. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

New Approaches in Vital Pulp Therapy in Permanent Teeth

PubMed Central

Ghoddusi, Jamileh; Forghani, Maryam; Parisay, Iman

2014-01-01

Vitality of dental pulp is essential for long-term tooth survival. The aim of vital pulp therapy is to maintain healthy pulp tissue by eliminating bacteria from the dentin-pulp complex. There are several different treatment options for vital pulp therapy in extensively decayed or traumatized teeth. Pulp capping or pulpotomy procedures rely upon an accurate assessment of the pulp status, and careful management of the remaining pulp tissue. The purpose of this review is to provide an overview of new approaches in vital pulp therapy in permanent teeth. PMID:24396371

Transforming growth factor-β-induced gene product-h3 inhibits odontoblastic differentiation of dental pulp cells.

PubMed

Serita, Suguru; Tomokiyo, Atsushi; Hasegawa, Daigaku; Hamano, Sayuri; Sugii, Hideki; Yoshida, Shinichiro; Mizumachi, Hiroyuki; Mitarai, Hiromi; Monnouchi, Satoshi; Wada, Naohisa; Maeda, Hidefumi

2017-06-01

The aim of this study was to investigate transforming growth factor-β-induced gene product-h3 (βig-h3) expression in dental pulp tissue and its effects on odontoblastic differentiation of dental pulp cells (DPCs). A rat direct pulp capping model was prepared using perforated rat upper first molars capped with mineral trioxide aggregate cement. Human DPCs (HDPCs) were isolated from extracted teeth. βig-h3 expression in rat dental pulp tissue and HDPCs was assessed by immunostaining. Mineralization of HDPCs was assessed by Alizarin red-S staining. Odontoblast-related gene expression in HDPCs was analyzed by quantitative RT-PCR. Expression of βig-h3 was detected in rat dental pulp tissue, and attenuated by direct pulp capping, while expression of interleukin-1β and tumor necrosis factor-α was increased in exposed pulp tissue. βig-h3 expression was also detected in HDPCs, with reduced expression during odontoblastic differentiation. The above cytokines reduced βig-h3 expression in HDPCs, and promoted their mineralization. Recombinant βig-h3 inhibited the expression of odontoblast-related genes and mineralization of HDPCs, while knockdown of βig-h3 gene expression promoted the expression of odontoblast-related genes in HDPCs. The present findings suggest that βig-h3 in DPCs may be involved in reparative dentin formation and that its expression is likely to negatively regulate this process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Antiseptics on Pulpal Healing under Calcium Hydroxide Pulp Capping: A Pilot Study

PubMed Central

Bal, Cenkhan; Alacam, Alev; Tuzuner, Tamer; Tirali, Resmiye Ebru; Baris, Emre

2011-01-01

Objectives: The objective of this pilot study was to evaluate the effects of three different antiseptic materials on healing processes of direct pulp therapies with Ca(OH)2 histopathologically. Methods: Twenty-eight upper and lower first molar teeth from 7 male Wistar rats were used in this study. Four cavities were prepared in each rat in four quadrants, and each quadrant represented different experimental groups. In Group I: 0.5% sodium hypochlorite (NaOCl); in Group II: 2% chlorhexidine digluconate (CHX); in Group III: 0.1% octenidine dihydrochloride (OCT); and in Group IV 0.9% sterile saline was applied to the exposure site with a sterile cotton pellet for 3 minutes. After hemorrhage control, the pulps were capped with hard setting Ca(OH)2 and, finally, restored with IRM. The animals were euthanized at 21 days post-operatively. After sacrificing, routine histological procedures were performed and evaluated statistically with non-parametric Kruskal-Wallis test among the groups and two-by-two comparisons by using the Mann-Whitney U test for inflammatory response and tissue organization scores at the confidence interval of 95%. Results: There were significant differences in inflammatory response and tissue organization scores between the groups (P<.05). Statistical evaluation of inflammatory response showed that Group IV was significantly different from Groups I, II and III separately with a higher inflammatory cell response (P<.05) whereas no significant differences were detected between the other groups in two-by-two comparisons (P>.05). Healthy coronal and radicular pulp tissue organization scores indicated that the Group I has better pulp tissue organization than Group IV and this was significantly different (P<.05) whereas no significant differences were observed between the other groups separately (P>.05). Conclusions: The antiseptic materials used in this study created an environment that, rather than saline solution, may affect clinical and histological success in a positive way. PMID:21769267

Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

PubMed

Goldberg, Michel; Njeh, Akram; Uzunoglu, Emel

2015-01-01

The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically.

Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

PubMed Central

Goldberg, Michel; Njeh, Akram; Uzunoglu, Emel

2015-01-01

The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically. PMID:26538825

Flow Line, Durafill VS, and Dycal toxicity to dental pulp cells: effects of growth factors

PubMed Central

Furey, Alyssa; Hjelmhaug, Julie; Lobner, Doug

2010-01-01

Introduction The objective was to determine the effects of growth factor treatment on dental pulp cell sensitivity to toxicity of two composite restoration materials, Flow Line and Durafill VS, and a calcium hydroxide pulp capping material, Dycal. Methods Toxicity of the dental materials to cultures of primary dental pulp cells was determined by the MTT metabolism assay. The ability of six different growth factors to influence the toxicity was tested. Results A 24 hour exposure to either Flow Line or Durafill VS caused approximately 40% cell death, while Dycal exposure caused approximately 80% cell death. The toxicity of Flow Line and Durafill VS was mediated by oxidative stress. Four of the growth factors tested (BMP-2, BMP-7, EGF, and TGF-β) decreased the basal MTT values while making the cells resistant to Flow Line and Durafill VS toxicity, except BMP-2 which made the cells more sensitive to Flow Line. Treatment with FGF-2 caused no change in basal MTT metabolism, prevented the toxicity of Durafill VS, but increased the toxicity of Flow Line. Treatment with IGF-I increased basal MTT metabolism and made the cells resistant to Flow Line and Durafill VS toxicity. None of the growth factors made the cells resistant to Dycal toxicity. Conclusions The results indicate that growth factors can be used to alter the sensitivity of dental pulp cells to commonly used restoration materials. The growth factors BMP-7, EGF, TGF-β, and IGF-I provided the best profile of effects, making the cells resistant to both Flow Line and Durafill VS toxicity. PMID:20630288

Assessment of the potential of Allium sativum oil as a new medicament for non-vital pulpotomy of primary teeth

PubMed Central

Mohammad, Shukry Gamal; Baroudi, Kusai

2015-01-01

Objective: The objective of this study was to compare the clinical and radiographic effects of Allium sativum oil and formocresol in nonvital pulpotomy in primary teeth. Materials and Methods: Twenty children ranging in age from 4 to 8 years were included in the study. In every one of those children, pulpotomy was indicated for the primary molars. Pulpotomy procedure was performed and the radicular pulp tissue of one molar was capped with A. sativum oil in a cotton pellet while the other molar was capped with formocresol. The teeth were evaluated clinically and radiographically before and after 6 months using standard clinical and radiographic criteria. Statistically, these results revealed significant difference between the radiographic findings of nonvital pulpotomy in primary molars with the two medicaments. Statistical analysis was performed using independent t-test and paired t-test at the significance level of α = 0.05. Results: A. sativum oil has potent antibacterial properties that enable it to combat intracanal microbes in the infected pulp of primary molars. Better results were obtained when A. sativum oil was used. Conclusion: A. sativum oil had more powerful effects than formocresol on the infected pulp of primary nonvital molars. PMID:26312232

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth.

PubMed

Lin, Hung-Pin; Tu, Han-Ping; Hsieh, Yu-Ping; Lee, Bor-Shiunn

2017-01-01

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide- co -glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA-lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV-Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA-lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA-lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA-lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA-lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA-lovastatin (100 μg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA-lovastatin (100 μg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA-lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA-lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.

Response of human dental pulp cells to a silver-containing PLGA/TCP-nanofabric as a potential antibacterial regenerative pulp-capping material.

PubMed

Cvikl, Barbara; Hess, Samuel C; Miron, Richard J; Agis, Hermann; Bosshardt, Dieter; Attin, Thomas; Schmidlin, Patrick R; Lussi, Adrian

2017-02-27

Damage or exposure of the dental pulp requires immediate therapeutic intervention. This study assessed the biocompatibility of a silver-containing PLGA/TCP-nanofabric scaffold (PLGA/Ag-TCP) in two in vitro models, i.e. the material adapted on pre-cultured cells and cells directly cultured on the material, respectively. Collagen saffolds with and without hyaluronan acid (Coll-HA; Coll) using both cell culturing methods and cells growing on culture plates served as reference. Cell viability and proliferation were assessed after 24, 48, and 72 h based on formazan formation and BrdU incorporation. Scaffolds were harvested. Gene expression of interleukin(IL)-6, tumor necrosis factor (TNF)-alpha, and alkaline phosphatase (AP) was assessed 24 h after stimulation. In both models formazan formation and BrdU incorporation was reduced by PLGA/Ag-TCP on dental pulp cells, while no significant reduction was found in cells with Coll and Coll-HA. Cells with PLGA/Ag-TCP for 72 h showed similar relative BrdU incorporation than cells stimulated with Coll and Coll-HA. A prominent increase in the pro-inflammatory genes IL-6 and TNF-α was observed when cells were cultured with PLGA/Ag-TCP compared to the other groups. This increase was parallel with a slight increase in AP expression. Overall, no differences between the two culture methods were observed. PLGA/Ag-TCP decreased viability and proliferation rate of human dental pulp cells and increased the pro-inflammatory capacity and alkaline phosphatase expression. Whether these cellular responses observed in vitro translate into pulp regeneration in vivo will be assessed in further studies.

Physicochemical properties and cytotoxicity of an experimental resin-based pulp capping material containing the quaternary ammonium salt and Portland cement.

PubMed

Yang, Y W; Yu, F; Zhang, H C; Dong, Y; Qiu, Y N; Jiao, Y; Xing, X D; Tian, M; Huang, L; Chen, J H

2018-01-01

To evaluate in vitro the physicochemical properties, cytotoxicity and calcium phosphate nucleation of an experimental light-curable pulp capping material composed of a resin with antibacterial monomer (MAE-DB) and Portland cement (PC). The experimental material was prepared by mixing PC with a resin containing MAE-DB at a 2 : 1 ratio. Cured pure resin containing MAE-DB served as control resin. ProRoot MTA and Dycal served as commercial controls. The depth of cure, degree of monomer conversion, water absorption and solubility of dry samples, calcium release, alkalinizing activity, calcium phosphate nucleation and the cytotoxicity of materials were evaluated. Statistical analysis was carried out using anova followed by Tukey's HSD test (equal variance assumed) or Tamhane test (equal variance not assumed) and independent-samples t-tests. The experimental material had a cure depth of 1.19 mm, and the mean degree of monomer conversion was 70.93% immediately post-cure and 88.75% at 24 h post-cure. The water absorption of the experimental material was between those of MTA and Dycal, and its solubility was significantly less (P < 0.05) than that of Dycal and higher than that of MTA. The experimental material exhibited continuous calcium release and an alkalinizing power between those of MTA and Dycal throughout the test period. Freshly set experimental material, control resin and all 24-h set materials had acceptable cytotoxicity. The experimental material, MTA and Dycal all exhibited the formation of apatite precipitates after immersion in phosphate-buffered saline. The experimental material possessed adequate physicochemical properties, low cytotoxicity and good calcium phosphate nucleation. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Capping a Pulpotomy with Calcium Aluminosilicate Cement: Comparison to Mineral Trioxide Aggregates

PubMed Central

Kramer, Phillip R.; Woodmansey, Karl F.; White, Robert; Primus, Carolyn M.; Opperman, Lynne A.

2014-01-01

Introduction Calcium aluminate cements have shown little affinity for bacterial growth, low toxicity, and immunogenicity when used as a restoration material, but calcium aluminate cements have not been tested in vivo in pulpotomy procedures. Methods To address this question, a calcium aluminate cement (Quick-Set) was tested along with 2 mineral trioxide aggregates, ProRoot MTA and MTA Plus. These cements were used as a capping agent after pulpotomy. Control rats had no pulpotomy, or the pulpotomy was not capped. Proinflammatory cytokines interleukin (IL)-1β and IL-1α were measured, and histology was performed at 30 and 60 days after capping. The nociceptive response was determined by measuring the lengthening of the rat's meal duration. Results and Conclusions: IL-1β and IL-1α concentrations were reduced in the capped teeth, but no differences were observed among the 3 cements. Dentinal bridging could be detected at both 30 and 60 days with each of the 3 cements, and the pulps were still vital 60 days after capping. Meal duration significantly shortened after placement of the 3 different cements, indicating a nociceptive response, but there were no differences among the materials. Calcium aluminate cements had similar properties to mineral trioxide aggregates and is a viable option for pulpotomy procedures. PMID:25146026

Biocompatibility Evaluation of Four Dentin Adhesives Used as Indirect Pulp Capping Materials

PubMed Central

Cortés, Olga; Bernabé, Antonia

2017-01-01

Background In many cases, the indirect pulp treatment (IPT) is an acceptable treatment for deciduous teeth with reversible pulp inflammation. Various medicaments have been used for IPT, ranging from calcium hydroxide and glass ionomers to dentin adhesives. Objective This in vitro trial aimed to measure cytotoxicity in a cell culture, comparing the following four adhesives: Xeno® V (XE), Excite® F DSC (EX), Adhese® OneF (AD) and Prime & Bond NT (PB). Materials and methods The adhesives were prepared according to the manufacturer’s instructions. After 24 hours of exposure, the cell viability was evaluated using a photometrical test (MTT test). Data were subjected to analysis of variance (ANOVA). Results Adhesives, the main component of which was 2-hydroxyethyl methacrylate (HEMA), were found to be less cytotoxic, while those that included the monomer urethane dimethacrylate (UDMA were the most cytotoxic) in their composition. The effects on cell viability assay varied between the adhesives assayed with statistically significant differences. Conclusions The results may support the argument that Adhese® OneF is the least cytotoxic of the adhesives assayed, and may be considered as an adhesive agent for indirect pulp treatment. However, Prime and Bond NT showed a reduced biocompatibility under the same conditions. PMID:28827848

Histological evaluation of direct pulp capping of rat pulp with experimentally developed low-viscosity adhesives containing reparative dentin-promoting agents.

PubMed

Suzuki, Masaya; Taira, Yoshihisa; Kato, Chikage; Shinkai, Koichi; Katoh, Yoshiroh

2016-01-01

This study examines the wound healing process in exposed rat pulp when capped with experimental adhesive resin systems. Experimental adhesive resin system for direct pulp capping was composed of primer-I (PI), -II (PII), and -III (PIII) and an experimental bonding agent (EBA). PI was Clearfil(®) SE Bond(®)/Primer (CSP) containing 5.0 wt% CaCl2, PII was PI containing 10 wt% nanofiller (Aerosil(®) 380), and PIII was CSP containing 5.0 wt% of compounds of equal moles of synthetic peptides (pA and pB) derived from dentin matrix protein 1. EBA was Clearfil(®) SE Bond(®)/Bond (CSB) containing 10 wt% hydroxyapatite powders. Three experimental groups were designed. PI was assigned to experimental Groups 1 and 3. PII was assigned to experimental Groups 2 and 3. PIII and EBA were assigned to all experimental adhesive groups. Control teeth were capped with calcium hydroxide preparation (Dycal(®)), and CSP and CSB were applied to the cavity. The rats were sacrificed after each observation period (14, 28, 56, and 112 days). The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation (RDF), and bacterial penetration. There were no significant differences among all the groups for all parameters and all observation periods (p>0.05, Kruskal-Wallis test). All groups showed initial RDF at 14 days postoperatively and extensive RDF until 112 days postoperatively. Groups 2 and 3 demonstrated higher quantity of mineralized dentin bridge formation compared with Group 1. Addition of nanofillers to the primer was effective in promoting high-density RDF. Experimentally developed adhesive resin systems induce the exposed pulp to produce almost the same quantity of reparative dentin as calcium hydroxide. However, we need further studies to elucidate whether the same results could be obtained in humans. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Dentinopulpar organ: biological basis of clinical response to Ca(OH)2 application].

PubMed

Gani, O; Crosa, M E

1989-01-01

We have studied the changes presented by mediate and immediate roentgenographic images of indirect pulp capping and pulpotomies. In the cases of indirect pulp capping it was observed an increase of radiolucidity in the places occupied by Ca(OH)2, and sclerotic dentin was present. In pulpotomies, it was found the dentin bridge, which thickness increases with time. The radiolucidity of pulp chamber occupied by Ca(OH)2 was greater in the long time treatment. The radiopacity of non-vital dentin of walls and floor chamber was increased too. It has suggested that Ca++ ion would have migrated from its place and probably would take part in the synthesis of sclerotic dentin, independently of the vitality of the tissue.

Eco-friendly Fibre from Recycled Polypropylene of Bottle Cap Waste and Lignin

NASA Astrophysics Data System (ADS)

Soekoco, A. S.; Basuki, A.; Mardiyati

2016-01-01

Ecofriendly fibre is one of potential alternatives to fulfill the rising demand in textile material supply which is limited due to the decreasing reserve of oil. Large amount of polypropylene waste from bottle cap and lignin as a byproduct from pulp industry are potential solutions. Grinded polypropylene bottle cap was blended with lignin powder in concentration of 5 wt. % processed by melt spinning at 170° C temperature. The fibres produced have an average diameter 170 and 250 micrometres. In view of the mechanical properties. the tensile strength is 11.9 MPa for fibre with 170 micrometres diameter and 14.7 MPa for fibre with 250 micrometres diameter. Fibre surface morphology was further studied using micron microscope. and the result shows black flocks spread in the fibre. indicating that the lignin does not blend evenly.

A Review on Vital Pulp Therapy in Primary Teeth

PubMed Central

Parisay, Iman; Ghoddusi, Jamileh; Forghani, Maryam

2015-01-01

Maintaining deciduous teeth in function until their natural exfoliation is absolutely necessary. Vital pulp therapy (VPT) is a way of saving deciduous teeth. The most important factors in success of VPT are the early diagnosis of pulp and periradicular status, preservation of the pulp vitality and proper vascularization of the pulp. Development of new biomaterials with suitable biocompatibility and seal has changed the attitudes towards preserving the reversible pulp in cariously exposed teeth. Before exposure and irreversible involvement of the pulp, indirect pulp capping (IPC) is the treatment of choice, but after the spread of inflammation within the pulp chamber and establishment of irreversible pulpitis, removal of inflamed pulp tissue is recommended. In this review, new concepts in preservation of the healthy pulp tissue in deciduous teeth and induction of the reparative dentin formation with new biomaterials instead of devitalization and the consequent destruction of vital tissues are discussed. PMID:25598803

Physiochemical properties of experimental nano-hybrid MTA

PubMed Central

Akhavan Zanjani, V; Tabari, K; Sheikh-Al-Eslamian, SM; Abrandabadi, AN

2017-01-01

Introduction: Development of new pulp capping agents has paved the way towards the preservation of pulp vitality, which is an important goal in restorative dentistry. This study sought to assess the calcium ion release, pH and setting of mineral trioxide aggregate (MTA) Angelus, an experimental formulation of nano-hybrid MTA containing nano-SiO2, nano-Al2O3 and nano-TiO2 and MTA Angelus plus nano-oxides. Methods: In this experimental study, five specimens from each material were placed in polypropylene tubes and immersed in a flask containing deionized distilled water. The quantity of calcium ions released into the solution from each material was measured at 15 minutes, one hour, and 24 hours by using atomic absorption spectroscopy. The pH of the solutions was measured by using a pH meter at the respective time points. The setting time was also assessed by using a Gilmore needle. Data were analyzed by using repeated measure ANOVA. Results: The quantity of released calcium ions was not significantly different among the groups (P=0.060). All materials were alkaline and the pH at 24 hours was significantly higher than the other two time points in all groups (P<0.001). The experimental group had the shortest and the MTA Angelus had the longest setting time. All materials were alkaline and capable of releasing calcium. Addition of nanoparticles to MTA Angelus significantly decreased the setting time but had no effect on the release of calcium ions or pH. Abbreviations: MTA = mineral trioxide aggregate, VPT = vital pulp therapy PMID:29075348

Nemesia Root Hair Response to Paper Pulp Substrate for Micropropagation

PubMed Central

Labrousse, Pascal; Delmail, David; Decou, Raphaël; Carlué, Michel; Lhernould, Sabine; Krausz, Pierre

2012-01-01

Agar substrates for in vitro culture are well adapted to plant micropropagation, but not to plant rooting and acclimatization. Conversely, paper-pulp-based substrates appear as potentially well adapted for in vitro culture and functional root production. To reinforce this hypothesis, this study compares in vitro development of nemesia on several substrates. Strong differences between nemesia roots growing in agar or in paper-pulp substrates were evidenced through scanning electron microscopy. Roots developed in agar have shorter hairs, larger rhizodermal cells, and less organized root caps than those growing on paper pulp. In conclusion, it should be noted that in this study, in vitro microporous substrates such as paper pulp lead to the production of similar root hairs to those found in greenhouse peat substrates. Consequently, if agar could be used for micropropagation, rooting, and plant acclimatization, enhancement could be achieved if rooting stage was performed on micro-porous substrates such as paper pulp. PMID:22312323

Nemesia root hair response to paper pulp substrate for micropropagation.

PubMed

Labrousse, Pascal; Delmail, David; Decou, Raphaël; Carlué, Michel; Lhernould, Sabine; Krausz, Pierre

2012-01-01

Agar substrates for in vitro culture are well adapted to plant micropropagation, but not to plant rooting and acclimatization. Conversely, paper-pulp-based substrates appear as potentially well adapted for in vitro culture and functional root production. To reinforce this hypothesis, this study compares in vitro development of nemesia on several substrates. Strong differences between nemesia roots growing in agar or in paper-pulp substrates were evidenced through scanning electron microscopy. Roots developed in agar have shorter hairs, larger rhizodermal cells, and less organized root caps than those growing on paper pulp. In conclusion, it should be noted that in this study, in vitro microporous substrates such as paper pulp lead to the production of similar root hairs to those found in greenhouse peat substrates. Consequently, if agar could be used for micropropagation, rooting, and plant acclimatization, enhancement could be achieved if rooting stage was performed on micro-porous substrates such as paper pulp.

Use of Vital Pulp Therapies in Primary Teeth with Deep Caries Lesions.

PubMed

Dhar, Vineet; Marghalani, Abdullah A; Crystal, Yasmi O; Kumar, Ashok; Ritwik, Priyanshi; Tulunoglu, Ozlem; Graham, Laurel

2017-09-15

This manuscript presents evidence-based guidance on the use of vital pulp therapies for treatment of deep caries lesions in children. A guideline panel convened by the American Academy of Pediatric Dentistry formulated evidence-based recommendations on three vital pulp therapies: indirect pulp treatment (IPT; also known as indirect pulp cap), direct pulp cap (DPC), and pulpotomy. The basis of the guideline's recommendations was evidence from "Primary Tooth Vital Pulp Therapy: A Systematic Review and Meta-Analysis." (Pediatr Dent 2017;15;39[1]:16-23.) A systematic search was conducted in PubMed®/MEDLINE, Embase®, Cochrane Central Register of Controlled Trials, and trial databases to identify randomized controlled trials and systematic reviews addressing peripheral issues of vital pulp therapies such as patient preferences of treatment and impact of cost. Quality of the evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation approach; the evidence-to-decision framework was used to formulate a recommendation. The panel was unable to make a recommendation on superiority of any particular type of vital pulp therapy owing to lack of studies directly comparing these interventions. The panel recommends use of mineral trioxide aggregate (MTA) and formocresol in pulpotomy treatments; these are recommendations based on moderate-quality evidence at 24 months. The panel made weak recommendations regarding choice of medicament in both IPT (moderate-quality evidence [24 months], low quality evidence [48 months]) and DPC (very-low quality evidence [24 months]). Success of both treatments was independent of type of medicament used. The panel also recommends use of ferric sulfate (low-quality evidence), lasers (low-quality evidence), sodium hypochlorite (very low-quality evidence), and tricalcium silicate (very low-quality evidence) in pulpotomies; these are weak recommendations based on low-quality evidence. The panel recommended against the use of calcium hydroxide as pulpotomy medicament in primary teeth with deep caries lesions. Conclusions and practical implications: The guideline intends to inform the clinical practices with evidence-based recommendations on vital pulp therapies in primary teeth with deep caries lesions. These recommendations are based upon the best available evidence to-date.

Direct pulp capping of permanent teeth in New Zealand general dental practice--a practice based research study.

PubMed

Friedlander, L; McElroy, K; Daniel, B; Cullinan, M; Hanlin, S

2015-06-01

This study aimed to investigate treatment protocols and opinions towards direct pulp capping (DPC) amongst New Zealand (NZ) general dental practitioners (GDP) through a Practice Based Research Network (PBRN) study. Mixed-methods approach using qualitative thematic and quantitative analysis. An on-line survey containing Likert scale items and open-ended questions was distributed to GDPs on the Dental Council of New Zealand (DCNZ) register (2012) to collect information on practitioner demographics, treatment protocols, continuing professional development (CPD) and philosophies towards DPC. RESULTs: Two hundred and ten GDPs from North and South Islands providing care in main centres and rural areas engaged with the PBRN and participated in the study. Almost all performed DPC treatment although it was not a common procedure. DPC was perceived as 'successful' or 'very successful' by 95% of respondents, mostly for cases of reversible pulpitis. Most provided DPC for patients of all ages but younger patients were perceived to have the best clinical outcomes. Calcium hydroxide and MTA were the most commonly used materials for DPC. MTA was believed to have the best outcome but cost and handling properties were barriers to its use. The majority of respondents had participated in CPD related to vital pulp therapy and regarded this treatment as conservative and providing time and financial benefits compared with more invasive treatment. Clinicians' timeframes for assessing healing were variable, and combined clinical and radiographic findings were considered most useful. New Zealand dentists perceive DPC as a successful and conservative treatment in selected cases. The findings have provided insights into engagement of NZ dentists in using research to inform everyday clinical practice through a PBRN study.

Effect of white mineral trioxide aggregate compared with biomimetic carbonated apatite on dentine bridge formation and inflammatory response in a dental pulp model.

PubMed

Danesh, F; Vahid, A; Jahanbani, J; Mashhadiabbas, F; Arman, E

2012-01-01

  To evaluate the effects of apatite precipitation on the biocompatibility and hard tissue induction properties of white mineral trioxide aggregate (WMTA) in a dental pulp model.   Pulp exposures were created on the axial walls of 32 sound canine teeth of eight dogs. Four additional sound teeth served as controls. The pulps were capped either with WMTA or apatite derivatives [biomimetic carbonated apatite (BCAp)] in the interaction of WMTA with a synthetic tissue fluid and restored with zinc oxide-eugenol cement. After 7 and 70 days, the animals were killed, and the histological specimens taken from the teeth were stained with haematoxylin and eosin for histomorphological evaluation. The Brown and Brenn technique was employed to stain bacteria. The data were subjected to nonparametric Kruskall-Wallis analysis and Mann-Whitney U_tests.   Biomimetic carbonated apatite did not induce hard tissue bridge formation. WMTA performed significantly better than BCAp in this respect at both periods (P < 0.05). BCAp was associated with a significantly greater inflammatory response as compared with WMTA after 7 days (P < 0.05). Both materials were associated with similar reactions after 70 days (P >0.05).   White mineral trioxide aggregate induced hard tissue formation via a mechanism other than that postulated via apatite formation. © 2011 International Endodontic Journal.

Odontogenic Differentiation of Human Dental Pulp Stem Cells Stimulated by the Calcium Phosphate Porous Granules

PubMed Central

Nam, Sunyoung; Won, Jong-Eun; Kim, Cheol-Hwan; Kim, Hae-Won

2011-01-01

Effects of three-dimensional (3D) calcium phosphate (CaP) porous granules on the growth and odontogenic differentiation of human dental pulp stem cells (hDPSCs) were examined for dental tissue engineering. hDPSCs isolated from adult human dental pulps were cultured for 3-4 passages, and populated on porous granules. Cell growth on the culture dish showed an ongoing increase for up to 21 days, whereas the growth on the 3D granules decreased after 14 days. This reduction in proliferative potential on the 3D granules was more conspicuous under the osteogenic medium conditions, indicating that the 3D granules may induce the odontogenic differentiation of hDPSCs. Differentiation behavior on the 3D granules was confirmed by the increased alkaline phosphatase activity, up-regulation of odontoblast-specific genes, including dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP1) by quantitative polymerase chain reaction, and greater level of dentin sialoprotein synthesis by western blot. Moreover, the cellular mineralization, as assessed by Alizarin red S and calcium quantification, was significantly higher in the 3D CaP granules than in the culture dish. Taken all, the 3D CaP porous granules should be useful for dental tissue engineering in combination with hDPSCs by providing favorable 3D substrate conditions for cell growth and odontogenic development. PMID:21772958

Oxidative stress in patients with endodontic pathologies

PubMed Central

Vengerfeldt, Veiko; Mändar, Reet; Saag, Mare; Piir, Anneli; Kullisaar, Tiiu

2017-01-01

Background Apical periodontitis (AP) is an inflammatory disease affecting periradicular tissues. It is a widespread condition but its etiopathogenetic mechanisms have not been completely elucidated and the current treatment options are not always successful. Purpose To compare oxidative stress (OxS) levels in the saliva and the endodontium (root canal [RC] contents) in patients with different endodontic pathologies and in endodontically healthy subjects. Patients and methods The study group of this comparison study included 22 subjects with primary chronic apical periodontitis (pCAP), 26 with posttreatment or secondary chronic apical periodontitis (sCAP), eight with acute periapical abscess, 13 with irreversible pulpitis, and 17 healthy controls. Resting saliva samples were collected before clinical treatment. Pulp samples (remnants of the pulp, tooth tissue, and/or previous root filling material) were collected under strict aseptic conditions using the Hedström file. The samples were frozen to −80°C until analysis. OxS markers (myeloperoxidase [MPO], oxidative stress index [OSI], 8-isoprostanes [8-EPI]) were detected in the saliva and the endodontium. Results The highest MPO and 8-EPI levels were seen in pCAP and pulpitis, while the highest levels of OSI were seen in pCAP and abscess patients, as well as the saliva of sCAP patients. Controls showed the lowest OxS levels in both RC contents and saliva. Significant positive correlations between OxS markers, periapical index, and pain were revealed. Patients with pain had significantly higher OxS levels in both the endodontium (MPO median 27.9 vs 72.6 ng/mg protein, p=0.004; OSI 6.0 vs 10.4, p<0.001; 8-EPI 50.0 vs 75.0 pg/mL, p<0.001) and saliva (MPO 34.2 vs 117.5 ng/mg protein, p<0.001; 8-EPI 50.0 vs 112.8 pg/mL, p<0.001) compared to pain-free subjects. Conclusion OxS is an important pathomechanism in endodontic pathologies that is evident at both the local (RC contents) and systemic (saliva) level. OxS is significantly associated with dental pain and bone destruction. PMID:28894386

Oxidative stress in patients with endodontic pathologies.

PubMed

Vengerfeldt, Veiko; Mändar, Reet; Saag, Mare; Piir, Anneli; Kullisaar, Tiiu

2017-01-01

Apical periodontitis (AP) is an inflammatory disease affecting periradicular tissues. It is a widespread condition but its etiopathogenetic mechanisms have not been completely elucidated and the current treatment options are not always successful. To compare oxidative stress (OxS) levels in the saliva and the endodontium (root canal [RC] contents) in patients with different endodontic pathologies and in endodontically healthy subjects. The study group of this comparison study included 22 subjects with primary chronic apical periodontitis (pCAP), 26 with posttreatment or secondary chronic apical periodontitis (sCAP), eight with acute periapical abscess, 13 with irreversible pulpitis, and 17 healthy controls. Resting saliva samples were collected before clinical treatment. Pulp samples (remnants of the pulp, tooth tissue, and/or previous root filling material) were collected under strict aseptic conditions using the Hedström file. The samples were frozen to -80°C until analysis. OxS markers (myeloperoxidase [MPO], oxidative stress index [OSI], 8-isoprostanes [8-EPI]) were detected in the saliva and the endodontium. The highest MPO and 8-EPI levels were seen in pCAP and pulpitis, while the highest levels of OSI were seen in pCAP and abscess patients, as well as the saliva of sCAP patients. Controls showed the lowest OxS levels in both RC contents and saliva. Significant positive correlations between OxS markers, periapical index, and pain were revealed. Patients with pain had significantly higher OxS levels in both the endodontium (MPO median 27.9 vs 72.6 ng/mg protein, p =0.004; OSI 6.0 vs 10.4, p <0.001; 8-EPI 50.0 vs 75.0 pg/mL, p <0.001) and saliva (MPO 34.2 vs 117.5 ng/mg protein, p <0.001; 8-EPI 50.0 vs 112.8 pg/mL, p <0.001) compared to pain-free subjects. OxS is an important pathomechanism in endodontic pathologies that is evident at both the local (RC contents) and systemic (saliva) level. OxS is significantly associated with dental pain and bone destruction.

[The application of laser in endodontics].

PubMed

He, W X; Liu, N N; Wang, X L; He, X Y

2016-08-01

Since laser was introduced in the field of medicine in 1970's, its application range has continuously expanded. The application of laser in endodontics also increased due to its safety and effectiveness in dental treatments. The majority of the laser application researches in dentistry focused on dentin hypersensitivity, removal of carious tissues, tooth preparations, pulp capping or pulpotomy, and root canal treatment. In this article, we reviewed literature on the effects of laser in the treatments of dental and pulp diseases.

Assessment of the potential of Allium sativum oil as a new medicament for non-vital pulpotomy of primary teeth.

PubMed

Mohammad, Shukry Gamal; Baroudi, Kusai

2015-01-01

The objective of this study was to compare the clinical and radiographic effects of Allium sativum oil and formocresol in nonvital pulpotomy in primary teeth. Twenty children ranging in age from 4 to 8 years were included in the study. In every one of those children, pulpotomy was indicated for the primary molars. Pulpotomy procedure was performed and the radicular pulp tissue of one molar was capped with A. sativum oil in a cotton pellet while the other molar was capped with formocresol. The teeth were evaluated clinically and radiographically before and after 6 months using standard clinical and radiographic criteria. Statistically, these results revealed significant difference between the radiographic findings of nonvital pulpotomy in primary molars with the two medicaments. Statistical analysis was performed using independent t-test and paired t-test at the significance level of α = 0.05. A. sativum oil has potent antibacterial properties that enable it to combat intracanal microbes in the infected pulp of primary molars. Better results were obtained when A. sativum oil was used. A. sativum oil had more powerful effects than formocresol on the infected pulp of primary nonvital molars.

Evaluation of mineral trioxide aggregate (MTA) versus calcium hydroxide cement (Dycal(®) ) in the formation of a dentine bridge: a randomised controlled trial.

PubMed

Leye Benoist, Fatou; Gaye Ndiaye, Fatou; Kane, Abdoul Wakhabe; Benoist, Henri Michel; Farge, Pierre

2012-02-01

To assess the effectiveness of mineral trioxide aggregate (MTA) used as an indirect pulp-capping material in human molar and premolar teeth. We conducted a clinical evaluation of 60 teeth, which underwent an indirect pulp-capping procedure with either MTA or calcium hydroxide cement (Dycal(®) ). Calcium hydroxide was compared with MTA and the thickness of the newly formed dentine was measured at regular time intervals. The follow-up was at 3 and 6 months, and dentine formation was monitored by radiological measurements on digitised images using Mesurim Pro(®) software. At 3 months, the clinical success rates of MTA and calcium hydroxide were 93% and 73%, respectively (P = 0.02). At 6 months, the success rate was 89.6% with MTA, and remained steady at 73% with calcium hydroxide (P = 0.63). The mean initial residual dentine thickness was 0.23 mm, and increased by 0.121 mm with MTA and by 0.136 mm with calcium hydroxide at 3 months. At 6 months, there was an increase of 0.235 mm with MTA and of 0.221 mm with calcium hydroxide.   A higher success rate was observed in the MTA group relative to the Dycal(®) group after 3 months, which was statistically significant. After 6 months, no statistically significant difference was found in the dentine thickness between the two groups. Additional histological investigations are needed to support these findings. © 2012 FDI World Dental Federation.

Fibroblast growth factor-2 regulates the cell function of human dental pulp cells.

PubMed

Shimabukuro, Yoshio; Ueda, Maki; Ozasa, Masao; Anzai, Jun; Takedachi, Masahide; Yanagita, Manabu; Ito, Masako; Hashikawa, Tomoko; Yamada, Satoru; Murakami, Shinya

2009-11-01

Homeostasis and tissue repair of dentin-pulp complex are attributed to dental pulp tissue and several growth factors. Dental pulp cells play a pivotal role in homeostasis of dentin-pulp complex and tissue responses after tooth injury. Among these cytokines, fibroblast growth factor (FGF)-2 has multifunctional biologic activity and is known as a signaling molecule that induces tissue regeneration. In this study, we examined the effects of FGF-2 on growth, migration, and differentiation of human dental pulp cells (HDPC). HDPC were isolated from healthy dental pulp. Cellular response was investigated by [(3)H]-thymidine incorporation into DNA. Cytodifferentiation was examined by alkaline phosphatase (ALPase) assay and cytochemical staining of calcium by using alizarin red. Migratory activity was determined by counting the cells migrating into cleared area that had introduced with silicon block. FGF-2 activated HDPC growth and migration but suppressed ALPase activity and calcified nodule formation. Interestingly, HDPC, which had been pretreated with FGF-2, showed increased ALPase activity and calcified nodule formation when subsequently cultured without FGF-2. These results suggest that FGF-2 potentiates cell growth and accumulation of HDPC that notably did not disturb cytodifferentiation of the cells later. Thus, FGF-2 is a favorable candidate for pulp capping agent. These results provide new evidence for the possible involvement of FGF-2 not only in homeostasis but also in regeneration of dentin-pulp complex.

Inflammatory and immunological aspects of dental pulp repair

PubMed Central

Goldberg, Michel; Farges, Jean-Christophe; Lacerda-Pinheiro, Sally; Six, Ngampis; Jegat, Nadège; Decup, Frank; Septier, Dominique; Carrouel, Florence; Durand, Stéphanie; Chaussain-Miller, Catherine; DenBesten, Pamela; Veis, Arthur; Poliard, Anne

2010-01-01

The repair of dental pulp by direct capping with calcium hydroxide or by implantation of bioactive extracellular matrix (ECM) molecules implies a cascade of four steps: a moderate inflammation, the commitment of adult reserve stem cells, their proliferation and terminal differentiation. The link between the initial inflammation and cell commitment is not yet well established but appears as a potential key factor in the reparative process. Either the release of cytokines due to inflammatory events activates resident stem (progenitor) cells, or inflammatory cells or pulp fibroblasts undergo a phenotypic conversion into osteoblast/odontoblast-like progenitors implicated in reparative dentin formation. Activation of antigen-presenting dendritic cells by mild inflammatory processes may also promote osteoblast/odontoblast-like differentiation and expression of ECM molecules implicated in mineralization. Recognition of bacteria by specific odontoblast and fibroblast membrane receptors triggers an inflammatory and immune response within the pulp tissue that would also modulate the repair process. PMID:18602009

Depth and activity of carious lesions as indicators for the regenerative potential of dental pulp after intervention.

PubMed

Bjørndal, Lars; Demant, Sune; Dabelsteen, Sally

2014-04-01

Studies on dental regeneration involving interventions for pulp therapy such as regeneration and revascularization procedures are promising for the injured tooth; however, a complete replication of the original pulp tissue does not seem to take place. In cases in which we wish to preserve or maintain parts of the pulp during treatment, it is apparent that the effectiveness of healing or biological regeneration is dependent on the degree of inflammation of the pulp tissue. Thus, the control or prevention of a pulp infection is still a major issue for the clinicians. Data indicate that the typical reason for performing endodontic treatment is deep caries. The biological concept of vital pulp therapy associated with deep caries takes the treatment and evaluation of the unexposed as well as the exposed pulp into account. Interestingly, the clinical diagnosis is typically the same. Deep caries with reversible pulpitis may receive differing treatments such as excavation procedures aiming to avoid pulp exposure or more pulp invasive treatments such as pulp capping or pulpotomy. This should not be the case. Consequently, huge treatment variation is noted among clinicians based on the same caries diagnosis. Which treatment should be selected? High-quality trials are needed, and it is important to obtain information on the actual lesion depth and an estimate of the lesion activity before treatment. These may be basic indicators for the regenerative potential of dental pulp. Recent clinical trials dealing with the treatment of deep caries lesion are discussed, including pulp invasive and noninvasive concepts, to attempt to solve the task of getting the best clinical outcome for adult patients. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Clinical and histological evaluation of white ProRoot MTA in direct pulp capping.

PubMed

Iwamoto, Claudio E; Adachi, Erika; Pameijer, Cornelis H; Barnes, Douglas; Romberg, Elaine E; Jefferies, Steven

2006-04-01

To evaluate the clinical, radiographical and histological findings in human third molars in which mechanical pulp exposures were capped with white ProRoot mineral trioxide aggregate (WMTA). Forty-eight human third molars, caries-free or with incipient caries, scheduled to be extracted, were used and randomly divided into two groups: Group A: (n= 24) received WMTA and control Group B: (n= 24) received chemical set calcium hydroxide (Dycal). The teeth were isolated with rubber dam and Class I cavities prepared. Pulp exposure was performed using a sterile diamond bur and confirmed by frank bleeding. A sterile cotton pellet dipped in saline solution was placed over the exposure for 60 seconds. The preparation was then lightly rinsed with water and gently air-dried. WMTA or CH was placed over the exposure site followed by a small amount of a light-cured compomer. After etching with 35% phosphoric acid gel for 15 seconds, rinsing and blot drying, Prime and Bond NT adhesive was applied and light-cured. The cavity was then restored with a resin composite and light-cured. Evaluations were performed by phone after 7 days and clinically at 30 +/- 5 and 136 +/- 24 days, using standardized tests and radiographs. The teeth were extracted after 136 +/- 24 days; the roots were cut +/- 4-5 mm from the apex to allow for rapid fixation in 10% neutral buffered formalin. They were then processed for routine histological evaluation, embedded in paraffin, sectioned and stained with hematoxylin and eosin and Brown and Brenn for recognition of bacteria. Statistical analyses were performed using a Mann-Whitney U-test, a Chi-square test, a Fisher's exact test and an ANOVA. No significant differences in post-operative sensitivity were reported after 7 days between the two materials (P> 0.05). Clinical examination demonstrated no significant differences at 30 +/- 5 days (P> 0.05) and at 136 +/- 24 days (P> 0.05). Histological findings: 45 of 48 teeth were suitable for microscopic evaluation (22 with WMTA and 23 with CH). Twenty from the WMTA and 18 from the CH group had developed a bridge. No statistically significant differences were found for superficial and deep inflammatory cell response (P> 0.05), presence of a dentin bridge (P> 0.01), and pulp vitality (P> 0.01), between WMTA and calcium hydroxide. A statistically significant difference was found for the diameter of exposure (P< or = 0.05) between WMTA (x= 0.35 +/- 0.19 mm) and CH (x= 0.25 +/- 0.09 mm). Only a minimal association between clinical and histological findings could be established for either material.

Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

DOEpatents

Francis, Raymond

2012-11-06

Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

Modification of lignocellulosic materials by laccase

Treesearch

William Kenealy; John Klungness; Mandla Tshabalala; Roland Gleisner; Eric Horn; Masood Akhtar; Hilda Zulaica-Villagomez; Gisela Buschle-Diller

2003-01-01

Altering the surface properties of pulp can enhance binding, increase paper strength, and decrease the cost of fiber. In this study, we modified lignocellulosic materials (bark and pulp) with laccase and selected substrates to change the nature of the pulp surface. Modified pulps were evaluated by the amount of methylene blue (a cationic dye) that would bind to the...

Effects of Various Dental Materials on Alkaline Phosphatase Extracted from Pulp: An Experiment for the Biochemistry Laboratory.

ERIC Educational Resources Information Center

Thompson, Lorin R.

1980-01-01

A laboratory experiment that demonstrates the effects of various dental materials on a representative enzyme from the pulp is outlined. The experiment encourages students to consider the effects that various restorative materials and techniques might have on enzymes in the living pulp. (Author/MLW)

Cellulose, hemicelluloses, lignin and ash content of some organic materials and their suitability for use as paper pulp supplements.

PubMed

Ververis, C; Georghiou, K; Danielidis, D; Hatzinikolaou, D G; Santas, P; Santas, R; Corleti, V

2007-01-01

Freshwater algal biomass and orange and lemon peels were assessed as tissue paper pulp supplements. Cellulose and hemicellulose contents of algal biomass were 7.1% and 16.3%, respectively, whereas for citrus peels cellulose content ranged from 12.7% to 13.6% and hemicellulose from 5.3% to 6.1%. For all materials, lignin and ash content was 2% or lower, rendering them suitable for use as paper pulp supplements. The addition of algal biomass to paper pulp increased its mechanical strength significantly. However, brightness was adversely affected by chlorophyll. The addition of citrus peels in paper pulp had no effect on breaking length, increased bursting strength and decreased tearing resistance. Brightness was negatively affected at proportions of 10%, because citrus peel particles behave as coloured pigments. The cost of both materials is about 45% lower than that of conventional pulp, resulting in a 0.9-4.5% reduction in final paper price upon their addition to the pulp.

Cellulose esters synthesized using a tetrabutylammonium acetate and dimethylsulfoxide solvent system

NASA Astrophysics Data System (ADS)

Yu, Yongqi; Miao, Jiaojiao; Jiang, Zeming; Sun, Haibo; Zhang, Liping

2016-07-01

Cellulose acetate (CA) and cellulose acetate propionate (CAP) were homogeneously synthesized in a novel tetrabutylammonium acetate/dimethyl sulfoxide (DMSO) solvent system, without any catalyst, at temperatures below 70 °C. The molecular structures of the cellulose esters (CEs) and distributions of the substituents in the anhydroglucose repeating units were determined using 13C cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy, and the degree of substitution (DS) values were determined using 1H nuclear magnetic resonance spectroscopy. The structures of the CEs, regenerated cellulose (RC), and pulp were determined using Fourier transform infrared spectroscopy. The thermal properties of the products were determined using thermogravimetric analysis. The temperatures of initial decomposition of the CEs were up to 40 °C higher than those of the RC and pulp. All the CEs were highly soluble in DMSO, but were insoluble in acetone. CAs with DS values less than 2.6 swelled or were poorly dissolved in CHCl3, but those with DS values above 2.9 dissolved rapidly. CAPs with DS values above 2.6 had good solubilities in ethyl acetate.

Evaluation of a value prior to pulping-thermomechanical pulp business concept. Part 2.

Treesearch

Ted Bilek; Carl Houtman; Peter Ince

2011-01-01

Value Prior to Pulping (VPP) is a novel biorefining concept for pulp mills that includes hydrolysis extraction of hemicellulose wood sugars and acetic acid from pulpwood prior to pulping. The concept involves conversion of wood sugars via fermentation to fuel ethanol or other chemicals and the use of remaining solid wood material in the pulping process. This paper...

Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study

NASA Astrophysics Data System (ADS)

Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Soares, Luís Eduardo Silva; Santo, Ana Maria do Espírito; Martin, Airton Abraha~o.; Puppin-Rontani, Regina Maria

2012-07-01

We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (μEDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. μEDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (p<0.05). Differences were observed among groups for the 960 cm-1 peak. Ca and P content differences were significant (SH5>NT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.

Characterization of dental pulp defect and repair in a canine model.

PubMed

Yildirim, Sibel; Can, Alp; Arican, Mustafa; Embree, Mildred C; Mao, Jeremy J

2011-12-01

To explore a relationship between the size of pulp chamber perforation and reparative dentin formation in a canine model. Pulp defects were created in the pulp chambers of maxillary and mandibular premolars (N = 64) in 17 healthy mongrel dogs in three different sizes (diameter/depth: 1/1, 2/1, and 2/2 mm3) with sterile round burs under general anesthesia. The perforations were immediately capped with hard-setting calcium hydroxide (CH) in the control group or sealed with Teflon membrane (TM) in the experimental group, followed by restoration with reinforced zinc oxide eugenol cement in vivo. Seven and 30 days after pulp chamber perforation and restoration all treated and control premolars were extracted and prepared for histomorphometric and statistical analyses. Reparative dentin formation was more pronounced for defect sizes up to 2/1 mm3 when treated with CH, and completely bridged the surgically created dentin defects only after 30 days. However, reparative dentin upon CH treatment failed to completely bridge pulp chamber exposure for 2/2 defects. By contrast, TM treatment only yielded mild reparative dentin bridging for defects up to 1/1, but not for either 2/1 or 2/2 defects at 30 days. Inflammatory responses of the exposed dental pulp tissue were more robust with the TM group than with the CH group. Thus, dental pulp tissue possesses a capacity for spontaneous repair by the formation of reparative dentin in this preclinical model, but only up to a defect size of -2 mm in diameter and 1 mm in depth. All observations are based on 30 days post-treatment in the canine model. These findings may serve as baseline for regenerative endodontic studies.

Study on Effectiveness of Processed and Unprocessed Black Liquor pulps in improving the properties of PPC mortar, Concrete and SCC

NASA Astrophysics Data System (ADS)

Ananthkumar, M.; Sathyan, Dhanya; Prabha, B.

2018-02-01

The cost of construction materials is increasing day by day because of high demand, scarcity of raw materials and high price of energy. From the view point of energy saving and over consumption of resources, the use of alternative constituents in construction materials is now a global concern. From this, the extensive research and development works towards exploring new ingredients are required for producing sustainable and environment friendly construction materials. Bagasse pulp liquor is one such material that can be used as a chemical admixture which is obtained as a by-product of paper manufacturing process. Around 5 million tons of bagasse pulp is obtained throughout the world each year. since the material is a waste product from paper industry, this can be changed as a admixture by its effective use in concrete. In the present investigation black pulp liquor is added to fresh concrete in different dosages, the concrete is then tested for workability, compressive strength, flexural, split tensile strength and setting time. From results it is shown that 1% replacement of water with black pulp liquor increases the fresh properties of the concrete, 2% replacement of water with black pulp liquor increases the mechanical properties of the concrete and acts as a set retarder.

Evaluation of blown down Alaska spruce and hemlock trees for pulp.

Treesearch

Donald J. Fahey; James M. Cahill

1983-01-01

Chips from Alaska hemlock and spruce trees blown down more than 10 years produced usable grades of viscose pulp. Yields of pulp from both species were about 2 percent lower for blowdown material than for control trees. Ash content was slightly higher in the pulp manufactured from blowdown timber than in pulp from control trees.

Effects of Extracellular pH on Dental Pulp Cells In Vitro.

PubMed

Hirose, Yujiro; Yamaguchi, Masaya; Kawabata, Shigetada; Murakami, Masashi; Nakashima, Misako; Gotoh, Momokazu; Yamamoto, Tokunori

2016-05-01

The proliferation and migration of dental pulp stem cells (DPSCs), a population comprised of dental pulp cells (DPCs), are important processes for pulp tissue repair. Dental pulp is exposed to changes in extracellular pH under various conditions, such as acidosis and exposure to caries-associated bacteria or a pulp capping agent. The objective of this study was to investigate the effects of extracellular pH on DPC proliferation and migration in vitro. To evaluate the proliferation potency of DPCs in various extracellular pH conditions, 2 × 10(4) cells were seeded into 35-mm dishes. The following day, we changed to NaHCO3-free medium, which was adjusted to different extracellular pH levels. After 120 hours, DPCs cultured in media from a pH of 3.5 to 5.5 showed cell death, those cultured in conditions from a pH of 6.5 to 7.5 showed growth arrest or cell death, and those grown at a pH of 9.5 showed mild proliferation. The migratory activity of living DPCs was not affected by extracellular pH. For histologic analysis, human teeth possessing a small abscess in the coronal pulp chamber were sliced for histologic analysis. Proliferating cell nuclear antigen (PCNA) immunolocalization was used as an index of cell proliferation for the sections and cultured cells. Acidic extracellular pH conditions resulted in reduced numbers of PCNA-positive DPCs in the dishes. As for pulp tissue affected by a small abscess, a PCNA-negative pulp cell layer was observed in close proximity to the infectious lesion. Together, these results suggest that an acidic extracellular pH condition is associated with DPC growth arrest or cell death. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Biomimetic remineralization of demineralized dentine using scaffold of CMC/ACP nanocomplexes in an in vitro tooth model of deep caries.

PubMed

Chen, Zhen; Cao, Shansong; Wang, Haorong; Li, Yanqiu; Kishen, Anil; Deng, Xuliang; Yang, Xiaoping; Wang, Yinghui; Cong, Changhong; Wang, Huajun; Zhang, Xu

2015-01-01

Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm) to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC) material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID).

Biomimetic Remineralization of Demineralized Dentine Using Scaffold of CMC/ACP Nanocomplexes in an In Vitro Tooth Model of Deep Caries

PubMed Central

Chen, Zhen; Cao, Shansong; Wang, Haorong; Li, Yanqiu; Kishen, Anil; Deng, Xuliang; Yang, Xiaoping; Wang, Yinghui; Cong, Changhong; Wang, Huajun; Zhang, Xu

2015-01-01

Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm) to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC) material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID). PMID:25587986

Biomechanical pulping : a mill-scale evaluation

Treesearch

Masood Akhtar; Gary M. Scott; Ross E. Swaney; Mike J. Lentz; Eric G. Horn; Marguerite S. Sykes; Gary C. Myers

1999-01-01

Mechanical pulping process is electrical energy intensive and results in low paper strength. Biomechanical pulping, defined as the fungal treatment of lignocellulosic materials prior to mechanical pulping, has shown at least 30% savings in electrical energy consumption, and significant improvements in paper strength properties compared to the control at a laboratory...

Study of a hydraulic DCPA/CaO-based cement for dental applications.

PubMed

El Briak, Hasna; Durand, Denis; Boudeville, Philippe

2008-02-01

A CPC was obtained by mixing calcium hydrogenphosphate (DCPA: CaHPO(4)) and calcium oxide with either water or sodium phosphate (NaP) buffers. Physical and mechanical properties such as compressive strength (CS), initial (I) and final (F) setting times, cohesion time (T(C)), dough time (T(D)), swelling time (T(S)), dimensional and thermal behavior, injectability (t(100%)), antimicrobial properties, setting reaction kinetics, and powder stability over time were investigated by varying different parameters such as liquid-to-powder (L/P) ratio (0.35 to 0.7 mL g(-1)), molar calcium-to-phosphate (Ca/P) ratio (1.67 to 3), the pH (4, 7 or 9) and the concentration (0 to 1 M) of the NaP buffer. The best results were obtained with the pH 7 NaP buffer at a concentration of 0.75 M. With this liquid phase, physical and mechanical properties depended on the Ca/P and L/P ratios, varying from 3 to 11 MPa (CS), 6 to 10 min (I), 11 to 15 min (F), 15 to 45 min (T(S)), 3 to 12 min (t(100%)), 16 min (T(D)). This cement expanded during its setting (2.5-7%), and is thus appropriate for tight filling. Finally the cement has antimicrobial activity from Ca/P = 2 and the whole properties were conserved after 8 months storage. Given the mechanical, rheological and antimicrobial properties of this new DCPA/CaO-based cement, its use as root canal sealing or pulp capping material may be considered as similar to calcium hydroxide or ZnO/eugenol-based pastes, without or with a gutta-percha point.

Promotive Effect of Zinc Ions on the Vitality, Migration, and Osteogenic Differentiation of Human Dental Pulp Cells.

PubMed

An, Shaofeng; Gong, Qimei; Huang, Yihua

2017-01-01

Zinc is an essential trace element for proper cellular function and bone formation. However, its exact role in the osteogenic differentiation of human dental pulp cells (hDPCs) has not been fully clarified before. Here, we speculated that zinc may be effective to regulate their growth and osteogenic differentiation properties. To test this hypothesis, different concentrations (1 × 10 -5 , 4 × 10 -5 , and 8 × 10 -5  M) of zinc ions (Zn 2+ ) were added to the basic growth culture medium and osteogenic inductive medium. Cell viability and migration were measured by cell counting kit-8 (CCK-8) and transwell migration assay in the basic growth culture medium, respectively. The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the gene expression levels of selective osteogenic differentiation markers and zinc transporters. Alkaline phosphatase (ALP) activity analysis and alizarin red S staining were used to investigate the mineralization of hDPCs. Exposure of hDPCs to Zn 2+ stimulated their viability and migration capacity in a dose- and time-dependent manner. RT-qPCR assay revealed elevated expression levels of osteogenic differentiation-related genes and zinc transporters genes in various degrees. ALP activity was also increased with elevated Zn 2+ concentrations and extended culture periods, but enhanced matrix nodules formation were observed only in 4 × 10 -5 and 8 × 10 -5  M Zn 2+ groups. These findings suggest that specific concentrations of Zn 2+ could potentiate the vitality, migration, and osteogenic differentiation of hDPCs. We may combine optimum zinc element into pulp capping materials to improve their biological performance.

Properties of kenaf from various cultivars, growth and pulping conditions

Treesearch

James S. Han; Ernest S. Miyashita; Sara J. Spielvogel

1999-01-01

The physical properties of kenaf offer potential as an alternative raw material for the manufacture of paper. Investigations to date have not determined whether core and fiber should be pulped together or separately. Kenaf bast and core fibers of different cultivars were pulped under various kraft pulping conditions and physical properties: density, Canadian Standard...

Effect of biomaterials on angiogenesis during vital pulp therapy

PubMed Central

SAGHIRI, Mohammad Ali; ASATOURIAN, Armen; GARCIA-GODOY, Franklin; SHEIBANI, Nader

2016-01-01

This review intended to provide an overview of the effects of dental materials, used in dentin-pulp complex and dental pulp regeneration, on angiogenesis processes during regenerative endodontic procedures. An electronic search was performed in PubMed and MEDLINE databases via OVID using the keywords mentioned in the PubMed and MeSH headings for English language published articles from January 2005–April 2014 that evaluated the angiogenic properties of different dental materials used in regenerative endodontic procedures. Of the articles identified in an initial search, only 40 articles met the inclusion criteria set for this review. Vital pulp therapy materials might have positive effects on angiogenesis events, while most of the canal irrigating solutions and antibiotic pastes have anti-angiogenic activity except for EDTA. Future clinical studies will be helpful in defining the mechanisms of action for dental materials that promote or inhibit angiogenesis events at applied areas. PMID:27546854

Ten-Year Follow-Up of a Fragment Reattachment to an Anterior Tooth: A Conservative Approach.

PubMed

Mendes, Luiz; Laxe, Laisa; Passos, Leandro

2017-01-01

This report describes the 10-year follow-up data of a patient who underwent fragment reattachment to the maxillary central incisor after coronal fracture with pulp exposure as well as the procedures followed for functional and esthetic adjustments. A 9-year-old female patient presented at the clinic of dentistry at the State University of Rio de Janeiro with a coronal fracture and pulp exposure of the right maxillary central incisor that had occurred immediately after an accident. The intact tooth fragment was recovered at the accident site and stored in milk. The treatment plan followed was to perform direct pulp capping and tooth fragment reattachment. When the patient was 14 years old, adhesion between fragment and remaining tooth was lost, and fragment reattachment was performed. Five years later, the same tooth presented clinical discoloration and absence of sensitivity during pulp vitality tests. Subsequently, a new treatment plan was formulated, which included endodontic treatment, followed by nonvital tooth bleaching and light-cured composite resin restoration. An esthetic and natural-looking restoration was achieved. Tooth fragment reattachment is not a temporary restorative technique and requires functional and esthetic adjustments over time to maintain the biomimetic characteristics of traumatized anterior teeth and predictable outcomes.

Ten-Year Follow-Up of a Fragment Reattachment to an Anterior Tooth: A Conservative Approach

PubMed Central

Mendes, Luiz; Laxe, Laisa

2017-01-01

This report describes the 10-year follow-up data of a patient who underwent fragment reattachment to the maxillary central incisor after coronal fracture with pulp exposure as well as the procedures followed for functional and esthetic adjustments. A 9-year-old female patient presented at the clinic of dentistry at the State University of Rio de Janeiro with a coronal fracture and pulp exposure of the right maxillary central incisor that had occurred immediately after an accident. The intact tooth fragment was recovered at the accident site and stored in milk. The treatment plan followed was to perform direct pulp capping and tooth fragment reattachment. When the patient was 14 years old, adhesion between fragment and remaining tooth was lost, and fragment reattachment was performed. Five years later, the same tooth presented clinical discoloration and absence of sensitivity during pulp vitality tests. Subsequently, a new treatment plan was formulated, which included endodontic treatment, followed by nonvital tooth bleaching and light-cured composite resin restoration. An esthetic and natural-looking restoration was achieved. Tooth fragment reattachment is not a temporary restorative technique and requires functional and esthetic adjustments over time to maintain the biomimetic characteristics of traumatized anterior teeth and predictable outcomes. PMID:28740741

Wheat Bread with Pumpkin (Cucurbita maxima L.) Pulp
as a Functional Food Product.

PubMed

Różyło, Renata; Gawlik-Dziki, Urszula; Dziki, Dariusz; Jakubczyk, Anna; Karaś, Monika; Różyło, Krzysztof

2014-12-01

In this study, a new application of pumpkin pulp in bread production is shown. The aim of this work is to determine the influence of the addition of fresh pumpkin pulp directly into wheat flour on physical, sensorial and biological properties of bread. The bioaccessibility of active compounds was also studied. An increase in the addition of pumpkin pulp from 5 to 20% (converted to dry matter) caused a decrease of bread volume and increase of crumb hardness and cohesiveness. The sensory characteristics of the bread showed that a partial replacement of wheat flour with up to 10% of pumpkin pulp gave satisfactory results. The taste, aroma and overall acceptability of control bread and bread containing 5 or 10% of pulp had the highest degree of liking. The addition of higher levels of pumpkin pulp caused an unpleasant aroma and taste. Pumpkin pulp is a good material to complement the bread with potentially bioaccessible phenolics (including flavonoids) and, especially, with peptides. The highest antioxidant activity was observed, in most cases, of the samples with added 10 and 15% of pumpkin pulp. The addition of the pulp significantly enriched the bread with potentially bioaccessible angiotensin-converting enzyme (ACE) inhibitors. The highest activity was determined in the bread with 15 and 20% pumpkin pulp. ACE inhibitors from the tested bread were highly bioaccessible in vitro . Pumpkin pulp seems to be a valuable source of active compounds to complement the wheat bread. Adding the pulp directly to the wheat flour gives satisfactory baking results and reduces the cost of production. Additionally, pumpkin pulp is sometimes treated as waste material after the acquisition of seeds, thus using it as bread supplement also has environmental and economic benefits. Key words : pumpkin, bread, texture, antioxidants, bioaccessibility in vitro, angiotensin-converting enzyme (ACE) inhibition.

Enzyme resistant carbohydrate based micro-scale materials from sugar beet (Beta vulgaris L.) pulp for food and pharmaceutical applications

USDA-ARS?s Scientific Manuscript database

Bio-based micro scale materials are increasingly used in functional food and pharmaceutical applications. The present study produced carbohydrate-based micro scale tubular materials from sugar beet (Beta vulgaris L.) pulp (SBP), a by-product of sugar beet processing. The isolated carbohydrates wer...

[Biocompatibility of crown and bridge materials. 1. Substances in contact with dentin].

PubMed

Klotzer, W T

1989-11-01

It is mandatory that the materials and drugs used in restorative dentistry be free from side effects resulting in potential tooth loss or irreversible damage to vital dental tissues. Up to now there have been no reliable in vitro methods available for the evaluation of pulp reactions. Since numerous different materials and drugs are successively applied to prepared dentine, pulp reactions are caused by cumulative action, and the causative factors, except for extremely toxic substances, cannot be revealed by clinical and/or posttreatment studies alone. At present, the evaluation of pulp reactions must still rely on histologic studies using human or animal teeth. Reports on pulp reactions to materials and drugs are reviewed. Few dependable figures have been reported on pulp reactions to dentinal medication, "sterilization", disinfectants and on the biologic response to and effectiveness of varnishes, liners, desensitizing agents, smear-layer removers, etc. Resins and composite materials seem to provoke acute reactions, mainly by the heat generated during setting, and chronic reactions due to the stimulation of bacterial growth. Except for glass ionomer cements, most of the publications show a high degree of agreement on the tissue reactions to luting agents. Regarding dentine bonding agents, however, it has not been possible to draw any conclusions, so far.

Calcium silicate-based cements: composition, properties, and clinical applications.

PubMed

Dawood, Alaa E; Parashos, Peter; Wong, Rebecca H K; Reynolds, Eric C; Manton, David J

2017-05-01

Mineral trioxide aggregate (MTA) is a calcium silicate-based cement (CSC) commonly used in endodontic procedures involving pulpal regeneration and hard tissue repair, such as pulp capping, pulpotomy, apexogenesis, apexification, perforation repair, and root-end filling. Despite the superior laboratory and clinical performance of MTA in comparison with previous endodontic repair cements, such as Ca(OH) 2 , MTA has poor handling properties and a long setting time. New CSC have been commercially launched and marketed to overcome the limitations of MTA. The aim of the present review was to explore the available literature on new CSC products, and to give evidence-based recommendations for the clinical use of these materials. Within the limitations of the available data in the literature regarding the properties and performance of the new CSC, the newer products could be promising alternatives to MTA; however, further research is required to support this assumption. © 2015 Wiley Publishing Asia Pty Ltd.

Pulp response to high fluoride releasing glass ionomer, silver diamine fluoride, and calcium hydroxide used for indirect pulp treatment: An in-vivo comparative study

PubMed Central

Korwar, Atish; Sharma, Sidhartha; Logani, Ajay; Shah, Naseem

2015-01-01

Aims and Objectives: The study aims at determining pulp response of two high fluoride releasing materials silver diamine fluoride (SDF) and Type VII glass ionomer cement (GIC) when used as indirect pulp treatment (IPT) materials. Materials and Methods: Deep Class V cavities were made on four first premolars indicated for extraction for orthodontic reasons. SDF, Type VII GIC, and calcium hydroxide base are given in three premolars, and one is kept control. Premolars were extracted 6 weeks after the procedure and subjected to histopathological examination to determine the pulp response. The results were analyzed using Chi-square test. Results: No inflammatory changes were observed in any of the groups. Significantly more number of specimens in SDF and Type VII GIC groups showed tertiary dentin deposition (TDD) when compared to control group. No significant difference was seen in TDD when intergroup comparison was made. Odontoblasts were seen as short cuboidal cells with dense basophilic nucleus in SDF and Type VII GIC group. Conclusion: The study demonstrated TDD inducing ability of SDF and Type VII GIC and also established the biocompatibility when used as IPT materials. PMID:26321822

Summaries of Research, Fiscal Year 1992

DTIC Science & Technology

1992-01-01

needs, or between early exposure to fluoridated drinking water and treatment needs. - Three hundred seventy four female recruits have been surveyed at... fluoridated drinking water and treat- ment needs. An abstract was presented at the 1992 AADR Annual Meeting and Exhibition, July 1-4, Glasgow, Scotland...significant difference (p <.002) in subsequent root-canal (RCT) or extraction (EXT) when pulp capping was performed. When all caries could be removed

Enzymatic hydrolysis of potato pulp.

PubMed

Lesiecki, Mariusz; Białas, Wojciech; Lewandowicz, Grażyna

2012-01-01

Potato pulp constitutes a complicated system of four types of polysaccharides: cellulose, hemicellulose, pectin and starch. Its composition makes it a potential and attractive raw material for the production of the second generation bioethanol. The aim of this research project was to assess the usefulness of commercial enzymatic preparations for the hydrolysis of potato pulp and to evaluate the effectiveness of hydrolysates obtained in this way as raw materials for ethanol fermentation. Sterilised potato pulp was subjected to hydrolysis with commercial enzymatic preparations. The effectiveness of the preparations declared as active towards only one fraction of potato pulp (separate amylase, pectinase and cellulase activity) and mixtures of these preparations was analysed. The monomers content in hydrolysates was determined using HPLC method. The application of amylolytic enzymes for potato pulp hydrolysis resulted in the release of only 18% of raw material with glucose as the dominant (77%) constituent of the formed product. In addition, 16% galactose was also determined in it. The hydrolysis of the cellulose fraction yielded up to 35% raw material and the main constituents of the obtained hydrolysate were glucose (46%) and arabinose (40%). Simultaneous application of amylolytic, cellulolytic and pectinolytic enzymes turned out to be the most effective way of carrying out the process as its efficiency in this case reached 90%. The obtained hydrolysate contained 63% glucose, 25% arabinose and 12% other simple substances. The application of commercial enzymatic preparations made it possible to perform potato pulp hydrolysis with 90% effectiveness. This was achieved by the application of a complex of amylolytic, cellulolytic and pectinolytic enzymes and the hydrolysate obtained in this way contained, primarily, glucose making it a viable substrate for ethanol fermentation.

Vital pulp therapy with bipolar electrocoagulation after intentional pulp exposure of fixed prosthodontic abutments: a clinical report.

PubMed

Livaditis, G J

2001-10-01

A clinical protocol is described for the treatment of intentional and unavoidable exposed pulps during crown preparation. The protocol includes a definitive cavity preparation to create space in the exposed dentin for an adhesive pulp barrier; procedures to develop the highly desirable hybrid zone to prevent microleakage; the use of a specific resinous material that serves as a long-term pulp barrier with a relatively neutral and biocompatible impact on the pulp; and the use of precise bipolar electrocoagulation to provide durable hemostasis for restoration of the pulp wall and a relatively clot-free surgical wound to facilitate healing. The protocol involves the application of gentle surgical and restorative procedures to support the inherent healing process to restore the health of the pulp. The patient presented was part of a larger investigation and was selected in an attempt to identify a fixed prosthodontic application of the proposed pulp therapy protocol.

Vital Pulp Therapy—Current Progress of Dental Pulp Regeneration and Revascularization

PubMed Central

Zhang, Weibo; Yelick, Pamela C.

2010-01-01

Pulp vitality is extremely important for the tooth viability, since it provides nutrition and acts as biosensor to detect pathogenic stimuli. In the dental clinic, most dental pulp infections are irreversible due to its anatomical position and organization. It is difficult for the body to eliminate the infection, which subsequently persists and worsens. The widely used strategy currently in the clinic is to partly or fully remove the contaminated pulp tissue, and fill and seal the void space with synthetic material. Over time, the pulpless tooth, now lacking proper blood supply and nervous system, becomes more vulnerable to injury. Recently, potential for successful pulp regeneration and revascularization therapies is increasing due to accumulated knowledge of stem cells, especially dental pulp stem cells. This paper will review current progress and feasible strategies for dental pulp regeneration and revascularization. PMID:20454445

Wheat Bread with Pumpkin (Cucurbita maxima L.) Pulp
as a Functional Food Product

PubMed Central

Gawlik-Dziki, Urszula; Dziki, Dariusz; Jakubczyk, Anna; Karaś, Monika; Różyło, Krzysztof

2014-01-01

Summary In this study, a new application of pumpkin pulp in bread production is shown. The aim of this work is to determine the influence of the addition of fresh pumpkin pulp directly into wheat flour on physical, sensorial and biological properties of bread. The bioaccessibility of active compounds was also studied. An increase in the addition of pumpkin pulp from 5 to 20% (converted to dry matter) caused a decrease of bread volume and increase of crumb hardness and cohesiveness. The sensory characteristics of the bread showed that a partial replacement of wheat flour with up to 10% of pumpkin pulp gave satisfactory results. The taste, aroma and overall acceptability of control bread and bread containing 5 or 10% of pulp had the highest degree of liking. The addition of higher levels of pumpkin pulp caused an unpleasant aroma and taste. Pumpkin pulp is a good material to complement the bread with potentially bioaccessible phenolics (including flavonoids) and, especially, with peptides. The highest antioxidant activity was observed, in most cases, of the samples with added 10 and 15% of pumpkin pulp. The addition of the pulp significantly enriched the bread with potentially bioaccessible angiotensin-converting enzyme (ACE) inhibitors. The highest activity was determined in the bread with 15 and 20% pumpkin pulp. ACE inhibitors from the tested bread were highly bioaccessible in vitro. Pumpkin pulp seems to be a valuable source of active compounds to complement the wheat bread. Adding the pulp directly to the wheat flour gives satisfactory baking results and reduces the cost of production. Additionally, pumpkin pulp is sometimes treated as waste material after the acquisition of seeds, thus using it as bread supplement also has environmental and economic benefits. Key words: pumpkin, bread, texture, antioxidants, bioaccessibility in vitro, angiotensin-converting enzyme (ACE) inhibition PMID:27904316

Histological Evaluation to Study the Effects of Dental Amalgam and Composite Restoration on Human Dental Pulp: An in vivo Study

PubMed Central

Chandwani, Neelam D.; Pawar, Mansing G.; Tupkari, Jagdish V.; Yuwanati, Monal

2013-01-01

Objective To study and compare the effects of dental amalgam and composite restorations on human dental pulp. Materials and Methods One hundred sound premolars scheduled for orthodontic extraction were divided equally into two groups: group A, teeth restored with silver amalgam, and group B, teeth restored with composite resin. Each group was equally subdivided into two subgroups [extracted after 24 h (A-1 and B-1) or 7 days (A−2 and B−2)], and the histological changes in the pulp related to the two different materials at the two different intervals were studied. Results It was found that after 24 h, the inflammatory response of the pulp in teeth restored with amalgam and composite was similar (p = 1.00). However, after 7 days, the severity of the inflammatory response of the pulp in teeth restored with amalgam was less compared to that in teeth restored with composite (p = 0.045). Conclusion This study confirmed that amalgam continues to be the mechanically as well as biologically more competent restorative material. Composite could be a promising restorative material to satisfy esthetic needs for a considerable period of time. However, its biological acceptance is still in doubt. PMID:24217468

Low Temperature Soda-Oxygen Pulping of Bagasse.

PubMed

Yue, Fengxia; Chen, Ke-Li; Lu, Fachuang

2016-01-13

Wood shortages, environmental pollution and high energy consumption remain major obstacles hindering the development of today's pulp and paper industry. Energy-saving and environmental friendly pulping processes are still needed, especially for non-woody materials. In this study, soda-oxygen pulping of bagasse was investigated and a successful soda-oxygen pulping process for bagasse at 100 °C was established. The pulping parameters of choice were under active alkali charge of 23%, maximum cooking temperature 100 °C, time hold at maximum temperature 180 min, initial pressure of oxygen 0.6 MPa, MgSO4 charge 0.5%, and de-pithed bagasse consistency 12%. Properties of the resultant pulp were screened yield 60.9%, Kappa number 14, viscosity 766 dm³/kg, and brightness 63.7% ISO. Similar pulps were also obtained at 110 °C or 105 °C with a cooking time of 90 min. Compared with pulps obtained at higher temperatures (115-125 °C), this pulp had higher screened yield, brightness, and acceptable viscosity, while the delignification degree was moderate. These results indicated that soda-oxygen pulping at 100 °C, the lowest cooking temperature reported so far for soda-oxygen pulping, is a suitable process for making chemical pulp from bagasse. Pulping at lower temperature and using oxygen make it an environmental friendly and energy-saving pulping process.

Kraft pulp from budworm-infested jack pine

Treesearch

J. Y. Zhu; Gary C. Myers

2006-01-01

This study evaluated the quality of kraft pulp from bud-worm-infested jack pine. The logs were classified as merchantable live, suspect, or merchantable dead. Raw materials were evaluated through visual inspection, analysis of the chemical composition, SilviScan measurement of the density, and measurement of the tracheid length. Unbleached pulps were then refined using...

Regenerative endodontics--Creating new horizons.

PubMed

Dhillon, Harnoor; Kaushik, Mamta; Sharma, Roshni

2016-05-01

Trauma to the dental pulp, physical or microbiologic, can lead to inflammation of the pulp followed by necrosis. The current treatment modality for such cases is non-surgical root canal treatment. The damaged tissue is extirpated and the root canal system prepared. It is then obturated with an inert material such a gutta percha. In spite of advances in techniques and materials, 10%-15% of the cases may end in failure of treatment. Regenerative endodontics combines principles of endodontics, cell biology, and tissue engineering to provide an ideal treatment for inflamed and necrotic pulp. It utilizes mesenchymal stem cells, growth factors, and organ tissue culture to provide treatment. Potential treatment modalities include induction of blood clot for pulp revascularization, scaffold aided regeneration, and pulp implantation. Although in its infancy, successful treatment of damaged pulp tissue has been performed using principles of regenerative endodontics. This field is dynamic and exciting with the ability to shape the future of endodontics. This article highlights the fundamental concepts, protocol for treatment, and possible avenues for research in regenerative endodontics. © 2015 Wiley Periodicals, Inc.

Synthetic Light-Curable Polymeric Materials Provide a Supportive Niche for Dental Pulp Stem Cells.

PubMed

Vining, Kyle H; Scherba, Jacob C; Bever, Alaina M; Alexander, Morgan R; Celiz, Adam D; Mooney, David J

2018-01-01

Dental disease annually affects billions of patients, and while regenerative dentistry aims to heal dental tissue after injury, existing polymeric restorative materials, or fillings, do not directly participate in the healing process in a bioinstructive manner. There is a need for restorative materials that can support native functions of dental pulp stem cells (DPSCs), which are capable of regenerating dentin. A polymer microarray formed from commercially available monomers to rapidly identify materials that support DPSC adhesion is used. Based on these findings, thiol-ene chemistry is employed to achieve rapid light-curing and minimize residual monomer of the lead materials. Several triacrylate bulk polymers support DPSC adhesion, proliferation, and differentiation in vitro, and exhibit stiffness and tensile strength similar to existing dental materials. Conversely, materials composed of a trimethacrylate monomer or bisphenol A glycidyl methacrylate, which is a monomer standard in dental materials, do not support stem cell adhesion and negatively impact matrix and signaling pathways. Furthermore, thiol-ene polymerized triacrylates are used as permanent filling materials at the dentin-pulp interface in direct contact with irreversibly injured pulp tissue. These novel triacrylate-based biomaterials have potential to enable novel regenerative dental therapies in the clinic by both restoring teeth and providing a supportive niche for DPSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Durability of pulp fiber-cement composites

NASA Astrophysics Data System (ADS)

Mohr, Benjamin J.

Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness losses) during wet/dry cycling. SCMs have been found to be effective in mitigating composite degradation through several processes, including a reduction in the calcium hydroxide content, stabilization of monosulfate by maintaining pore solution pH, and a decrease in ettringite reprecipitation accomplished by increased binding of aluminum in calcium aluminate phases and calcium in the calcium silicate hydrate (C-S-H) phase.

Assessing the Impacts of Pulp Loading from Non-Dispersible Materials on Downstream Sewer Systems (WERF Report INFR1R14)

EPA Science Inventory

Abstract:This study subjected wipes from five different manufacturers to a variety of tests to determine if changes to their physical characteristics occur when introduced into a sewer systemand what effect the shredded material (pulp) has on the downstream sewer. Shredded and no...

Nanoindentation studies of paper

Treesearch

B.F. West; B.T. Hotle; J.E. Jakes; J.M. Considine; R.E. Rowlands; K.T. Turner

2008-01-01

Paper materials consist of a porous web of cellulose polymeric fibers held together by entanglement and fiber-to-fiber bonding. These materials usually contain lignin and hemicellulose carbohydrates remaining from the pulping process. Pulped fibers are a flattened ribbon shape on the order of 30 microns wide, 10 microns thick and from one to four mm long. Paper web...

Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

PubMed

Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

2010-10-01

The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cements

Prospects of rice straw as a raw material for paper making.

PubMed

Kaur, Daljeet; Bhardwaj, Nishi Kant; Lohchab, Rajesh Kumar

2017-02-01

Pulp and paper mills are indispensable for any nation as far as the growth of the nation is concerned. Due to fast growth in population, urbanization and industrialization, the demand and consumption of paper has increased tremendously. These put high load on our natural resources and force the industry to look for alternative raw material. Rice straw is a lignocellulosic material abundantly available in wood short countries like China, India, Bangladesh, etc. and can be used as raw material for this industry. Open burning of rice straw releases noxious green house gases to the air and poses serious threats to global air chemistry and human health. So, it is a dual benefit option (for farmers and industries) to use rice straw as a raw material in pulp and paper industry. Organosolv pulping using acids are the prominent choices of researchers to convert this residue into valuable pulp but in developed countries only. Developing world favours the soda and soda-AQ processes as these are economical. As a virtue of less lignin content in comparison to wood, rice straw requires less harsh conditions for cooking and can be easily pulped. Bleaching is a crucial step of paper making but also responsible for causing water pollution. Many studies revealed that during the process more than 500 chlorinated compounds are released that are highly toxic, bioaccumulative and carcinogenic in nature. Most of the industries over the globe switch on to the elemental chlorine free short sequence bleaching methods using chlorine dioxide, hypochlorite and hydrogen peroxide. This paper presented the effective need of ecofriendly, economically reliable pulping and bleaching sequences in case of rice straw to eliminate the problems of chlorinated compounds in wastewater of paper mills. Such approach of using waste as a raw material with its environmentally safe processing for making paper can prove to be valuable towards sustainable growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

An in-vitro study to compare the temperature rise in the pulp chamber by direct method using three different provisional restorative materials.

PubMed

Piplani, Ankita; Suresh Sajjan, M C; Ramaraju, A V; Tanwani, Tushar; Sushma, G; Ganathipathi, G; Jagdish, K; Agrawal, Anil

2016-01-01

The provisional restorative materials in fixed prosthodontics are basically bis-GMA resins which releases exothermic temperature while polymerization which can damage the pulp. Intrapulpal temperature exceeding 42.5°C found to result in irreversible damage to the pulp. The remaining thickness of dentine after tooth preparation control the conduction of heat released by the resins. (1) To quantify the temperature changes in the pulp chamber using different provisional restorative materials. (2) To evaluate the peak temperature time of different materials used. (3) To compare the intrapulpal temperature changes with a variation in the width of the finish line. Two intact mandibular molars were selected and designated as Specimen A and B. Tooth preparation was done to prepare a finish line of 1.2 mm and 1 mm width, respectively. Three provisional restorative materials were considered and they were grouped as Group I-Cool temp, Group II-Protemp-4, Group III-Integrity. A J thermocouple probe was placed into the pulp chamber to determine the rise in temperature. The temperature was recorded during polymerization at 30-s intervals until the peak temperature was reached. The same procedure was repeated for fabricating remaining provisional crowns. A total of 45 provisional crowns were fabricated for each specimen. Kruskal-Wallis test revealed that there was a significant difference in the temperature changes associated with the provisional restorative materials used. All the three provisional restorative materials were compared for 1.2 mm and 1 mm wide finish line. Integrity produced the highest temperature rise and the maximum temperature recorded was 40.2°C in 1.2 mm wide finish line. However, for a 1 mm wide finish line, Protemp-4 produced the highest temperature rise and the maximum temperature recorded was 40.3°C. It was observed that peak temperatures with Specimen B were more when compared with Specimen A. Cool temp showed least temperature rise in the pulp chamber. The order of rise in intrapulpal temperature in tested provisional materials using direct technique would be Cool temp, Integrity, and Protemp-4.

Effect of Setting Time on the Shear Bond Strength Between Biodentine and Composite

DTIC Science & Technology

2015-06-01

Methods: Sample cylinders (n=134) and Biodentine capsules were randomly assigned to groups based on the setting time allowed for Biodentine (Group 1...15 minutes, Group 2 = 1 hour, Group 3 = 24 hours, Group 4 = 2 weeks). Biodentine was prepared and placed in the wells of the acrylic cylinders and...widely used as a temporary intracanal medicament during root canal therapy, as a liner , and for direct and indirect pulp capping procedures. Although

Lasers in endodontics: an overview

NASA Astrophysics Data System (ADS)

Frentzen, Matthias; Braun, Andreas; Koort, Hans J.

2002-06-01

The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

Comparison on Bactericidal and Cytotoxic Effect of Silver Nanoparticles Synthesized by Different Methods

NASA Astrophysics Data System (ADS)

Mala, R.; Celsia, A. S. Ruby; Malathi Devi, S.; Geerthika, S.

2017-08-01

Biologically synthesized silver nanoparticle are biocompatible for medical applications. The present work is aimed to synthesize silver nanoparticle using the fruit pulp of Tamarindusindica and to evaluate its antibacterial and anticancer activity against lung cancercell lines. Antibacterial activity was assessed by well diffusion method. Cytotoxicity was evaluated using MTT assay. GC-MS of fruit pulp extract showed the presence of levoglucosenone, n-hexadecanoic acid, 9,12-octadecadienoic acid etc. Antioxidant activity of the fruit pulp was determined by DPPH assay, hydrogen peroxide scavenging assay and lipid peroxidation. The size of biologically synthesized silver nanoparticle varied from 50 nm to 76 nm. It was 59 nm to 98 nm for chemically synthesized silver nanoparticle. Biologically synthesized silver nanoparticle showed 26 mm inhibition zone against E. coli and chemically synthesized silver nanoparticle showed 20 mm. Antioxidant activity of fruit extract by DPPH showed 84 % reduction. The IC 50 of biologically synthesized silver nanoparticle against lung cancer cell lines was 48 µg/ml. It was 95 µg/ml for chemically synthesized silver nanoparticle. The increased activity of biologically synthesized silver nanoparticle was due to its smaller size, stability and the bioactive compounds capping the silver nanoparticle extracted from the fruit extract.

Scaffolds to Control Inflammation and Facilitate Dental Pulp Regeneration

PubMed Central

Colombo, John S.; Moore, Amanda N.; Hartgerink, Jeffrey D.; D’Souza, Rena N.

2014-01-01

In dentistry, the maintenance of a vital dental pulp is of paramount importance, as teeth devitalized by root canal treatment may become more brittle and prone to structural failure over time. Advanced carious lesions can irreversibly damage the dental pulp by propagating a sustained inflammatory response throughout the tissue. While the inflammatory response initially drives tissue repair, sustained inflammation has an enormously destructive effect on the vital pulp, eventually leading to total necrosis of the tissue and necessitating its removal. The implications of tooth devitalization have driven significant interest in the development of bioactive materials that facilitate the regeneration of damaged pulp tissues by harnessing the capacity of the dental pulp for self-repair. In considering the process by which pulpitis drives tissue destruction, it is clear that an important step in supporting the regeneration of pulpal tissues is the attenuation of inflammation. Macrophages, key mediators of the immune response, may play a critical role in the resolution of pulpitis due to their ability to switch to a pro-resolution phenotype. This process can be driven by the resolvins, a family of molecules derived from fatty acids that show great promise as therapeutic agents. In this review, we outline the importance of preserving the capacity of the dental pulp to self-repair through the rapid attenuation of inflammation. Potential treatment modalities, such as shifting macrophages to a pro-resolving phenotype with resolvins are described, and a range of materials known to support the regeneration of dental pulp are presented. PMID:24698696

Use of high-boiling point organic solvents for pulping oil palm empty fruit bunches.

PubMed

Rodríguez, Alejandro; Serrano, Luis; Moral, Ana; Pérez, Antonio; Jiménez, Luis

2008-04-01

Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, alpha-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170 degrees C and 90 min; and (b) 80% solvent, 180 degrees C and 150 min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636 mL/g and 17 degrees SR, respectively), and paper made from it the best breaking length (1709 m), stretch (1.95%), burst index (0.98 kN/g) and tear index (0.33 mNm(2)/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose.

Dental Pulp and Dentin Tissue Engineering and Regeneration – Advancement and Challenge

PubMed Central

Huang, George T.-J.

2012-01-01

Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cememtum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filled with an artificial rubber-like material is employed to treat the infection --commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcome of the current advancement and challenge in this line of research will be discussed. PMID:21196351

Impact of thermal pretreatment and MSW origin on composition and hydrolysability in a sugar platform biorefinery

NASA Astrophysics Data System (ADS)

Vaurs, L. P.; Heaven, S.; Banks, C. J.

2018-03-01

Municipal solid waste (MSW) is a widely available large volume source of lignocellulosic material containing a waste paper/cardboard mixture which can be converted into fermentable sugars via cellulolytic enzyme hydrolysis in a sugar platform biorefinery. Thermal pretreatments are generally applied to MSW to facilitate the extraction of the lignocellulosic material from recyclable materials (plastics, metals etc.) and improve the paper pulp conversion to sugars. Applying high temperature might enhance food waste solubilisation but may collapse cellulose fibre decreasing its hydrolysability. Low temperature pre-treatment will reduce the energy demand but might result in highly contaminated pulp. Preliminary results showed that the enzymatic hydrolysis performances were dependent on the MSW origins. Using 8 different samples, the impact of thermal pretreatment and MSW origin on pulp composition and hydrolysability was assessed in this work. Low pre-treatment temperature produced pulp which contained less lignocellulosic material but which hydrolysed to a higher degree than MSW treated at high temperatures. High temperature pre-treatment could have exposed more of the inhibiting lignin to cellulase. This information would have a significant economic impact on a commercial plant as expensive autoclave could be advantageously replaced by a cheaper process. Glucan conversions were also found to vary depending on the region, the recycling rate possibly because of the lower recycling rate resulting in the use of less paper additive in the material or the difference in paper production technology (chemical VS mechanical pulping). This could also be explained by the differences in paper composition.

Catalysis: A Potential Alternative to Kraft Pulping

Treesearch

Alan W. Rudie; Peter W. Hart

2014-01-01

A thorough analysis of the kraft pulping process makes it obvious why it has dominated for over a century as an industrial process with no replacement in sight. It uses low cost raw materials, collects and regenerates over 90% of the chemicals needed in the process, is indifferent to wood raw material and good at preserving the cellulose portion of the wood which is...

Catalysis: A Potential Alternative to Kraft Pulping

Treesearch

Alan W. Rudie; Peter W. Hart

2014-01-01

A thorough analysis of the kraft pulping process makes it obvious why it has dominated for over a century as an industrial process with no replacement in sight. It uses low-cost raw materials; collects and regenerates over 90% of the chemicals needed in the process; and is indifferent to wood raw material and good at preserving the cellulose portion of the wood, the...

Mechanisms for kappa reduction and color removal by xylanases

Treesearch

Thomas W. Jeffries; Mark Davis; Brian Rosin; Larry L. Landucci

1998-01-01

Xylanases reduce kappa and release UV- and visibly absorptive materials from kraft pulps. The extents of these actions depend on the origin and processing of the pulp, access of enzymes to the substrate, and the natures of the enzymes. Hexeneuronic acid (HexA) is a component of kraft pulp xylans that accounts for a fraction of the kappa content. It absorbs strongly in...

Method of treating contaminated HEPA filter media in pulp process

DOEpatents

Hu, Jian S.; Argyle, Mark D.; Demmer, Ricky L.; Mondok, Emilio P.

2003-07-29

A method for reducing contamination of HEPA filters with radioactive and/or hazardous materials is described. The method includes pre-processing of the filter for removing loose particles. Next, the filter medium is removed from the housing, and the housing is decontaminated. Finally, the filter medium is processed as pulp for removing contaminated particles by physical and/or chemical methods, including gravity, flotation, and dissolution of the particles. The decontaminated filter medium is then disposed of as non-RCRA waste; the particles are collected, stabilized, and disposed of according to well known methods of handling such materials; and the liquid medium in which the pulp was processed is recycled.

Prevalence of Coronal Pulp Stones and Its Relation with Systemic Disorders in Northern Indian Central Punjabi Population

PubMed Central

Bains, Sandeep Kumar; Bhatia, Archana; Singh, Harkanwal Preet; Biswal, Swati Swagatika; Kanth, Shashi; Nalla, Srinivas

2014-01-01

Aim. To estimate the prevalence of coronal pulp stones in the molar teeth of dental outpatients of Sunam, Sangrur district, Punjab, India, to report any association between occurrence of pulp stones with age, gender, dental arch, side, and dental status and to find out correlation between pulp stones with dental and systemic diseases. Materials and Methods. 500 routine dental outpatients within age group of 18–67 years were involved in the study. Molar bitewing of left and right side of each patient was taken with XCP bitewing instrument and size 2 film. The presence or absence of pulp stones was recorded. Chi-square analysis was used to record the prevalence of pulp stones and to compare it with demographic and systemic factors. Results. Overall prevalence of pulp stones was 41.8%. Pulp stones were significantly higher in maxilla (11.59%) than mandible (6.54%), left side than right side, and first molar than other molars. Higher numbers of pulp stones were recorded in patients with cardiovascular disease (38.89%) than with cholelithiasis and renal lithiasis. Conclusion. Pulp stones were higher in maxillary arch than mandibular arch and in females than males. Cardiovascular patients had higher number of pulp stones than other groups. PMID:24944821

Tissue engineering: Dentin - pulp complex regeneration approaches (A review).

PubMed

Hashemi-Beni, Batool; Khoroushi, Maryam; Foroughi, Mohammad Reza; Karbasi, Saeed; Khademi, Abbas Ali

2017-10-01

Dental pulp is a highly specialized tissue that preserves teeth. It is important to maintain the capabilities of dental pulp before a pulpectomy by creating a local restoration of the dentin-pulp complex from residual dental pulp. The articles identified were selected by two reviewers based on entry and exit criteria. All relevant articles indexed in PubMed, Springer, Science Direct, and Scopus with no limitations from 1961 to 2016 were searched. Factors investigated in the selected articles included the following key words: Dentin-Pulp Complex, Regeneration, Tissue Engineering, Scaffold, Stem Cell, and Growth Factors. Of the 233 abstracts retrieved, the papers which were selected had evaluated the clinical aspects of the application of dentin-pulp regeneration. Generally, this study has introduced a new approach to provoke the regeneration of the dentin-pulp complex after a pulpectomy, so that exogenous growth factors and the scaffold are able to induce cells and blood vessels from the residual dental pulp in the tooth root canal. This study further presents a new strategy for local regeneration therapy of the dentin-pulp complex. This review summarizes the current knowledge of the potential beneficial effects derived from the interaction of dental materials with the dentin-pulp complex as well as potential future developments in this exciting field. Copyright © 2017 Elsevier Ltd. All rights reserved.

In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials.

PubMed

Randall, Paul M; Yates, Brian J; Lal, Vivek; Darlington, Ramona; Fimmen, Ryan

2013-08-01

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness. Published by Elsevier Inc.

Histo-pathological study of pulp response to a composite resin restoration with two lining materials.

PubMed

Aoki, S; Ishikawa, T

1990-11-01

This histopathological study investigated the pulp reaction to a restoration system employing a posterior composite resin with or without the pulp protection of visible light curing calcium hydroxide composition and alpha-TCP cement lining to dentin. Black's class V cavities were prepared in 120 adult dog teeth. They were then extracted for histological examination. As a result of this study, their lining materials were found to be effective in pulp protection. To understand the pathological finding, the pH values of "Fulfil", "Universal bond", "VLC Dycal" and "Vitacemen Type II" were measured. The pH levels of "Fulfil" and "Universal Bond" were mildly acidic (4.79-5.18) before polymerization, with no subsequent changes. "VLC Dycal" was initially a strongly alkaline (11.75) and remained this condition. "Vitacemen Type II" was initially acidic (3.78), but eventually reached the milder acidity of 5.12 after 24 hours.

[Application of Fourier transform attenuated total reflection infrared spectroscopy in analysis of pulp and paper industry].

PubMed

Zhang, Yong; Cao, Chun-yu; Feng, Wen-ying; Xu, Ming; Su, Zhen-hua; Liu, Xiao-meng; Lü, Wei-jun

2011-03-01

As one of the most powerful tools to investigate the compositions of raw materials and the property of pulp and paper, infrared spectroscopy has played an important role in pulp and paper industry. However, the traditional transmission infrared spectroscopy has not met the requirements of the producing processes because of its disadvantages of time consuming and sample destruction. New technique would be needed to be found. Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) is an advanced spectroscopic tool for nondestructive evaluation and could rapidly, accurately estimate the production properties of each process in pulp and paper industry. The present review describes the application of ATR-FTIR in analysis of pulp and paper industry. The analysis processes will include: pulping, papermaking, environmental protecting, special processing and paper identifying.

Pulp properties resulting from different pretreatments of wheat straw and their influence on enzymatic hydrolysis rate.

PubMed

Rossberg, Christine; Steffien, Doreen; Bremer, Martina; Koenig, Swetlana; Carvalheiro, Florbela; Duarte, Luís C; Moniz, Patrícia; Hoernicke, Max; Bertau, Martin; Fischer, Steffen

2014-10-01

Wheat straw was subjected to three different processes prior to saccharification, namely alkaline pulping, natural pulping and autohydrolysis, in order to study their effect on the rate of enzymatic hydrolysis. Parameters like medium concentration, temperature and time have been varied in order to optimize each method. Milling the raw material to a length of 4mm beforehand showed the best cost-value-ratio compared to other grinding methods studied. Before saccharification the pulp can be stored in dried form, leading to a high yield of glucose. Furthermore the relation of pulp properties (i.e. intrinsic viscosity, Klason-lignin and hemicelluloses content, crystallinity, morphology) to cellulose hydrolysis is discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Red algae and their use in papermaking.

PubMed

Seo, Yung-Bum; Lee, Youn-Woo; Lee, Chun-Han; You, Hack-Chul

2010-04-01

Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. Copyright 2009 Elsevier Ltd. All rights reserved.

Enzymatic pulp upgrade for producing high-value cellulose out of a Kraft paper pulp.

PubMed

Hutterer, Christian; Kliba, Gerhard; Punz, Manuel; Fackler, Karin; Potthast, Antje

2017-07-01

The high-yield separation of polymeric parts from wood-derived lignocellulosic material is indispensable in biorefinery concepts. For the separation of cellulose and xylan from hardwood paper pulps to obtain pulps of high cellulose contents, simple alkaline extractions were found to be the most suitable technology, although having certain limitations. These are embodied by residual alkali resistant xylan incorporated in the pulp matrix. Further purification in order to produce pure cellulose with a low uniformity could be achieved selectively degrading residual xylan and depolymerizing the cellulose macromolecules by xylanase and cellulase. The latter help to adjust cellulose chain lengths for certain dissolving pulp grades while reducing the demand for ozone in subsequent TCF bleaching. Experiments applying different commercially available enzyme preparations revealed the dependency of xylanase performance on the residual xylan content in pulps being stimulated by additional cellulase usage. The action of the latter strongly depends on the cellulose allomorphy confirming the impact of the pulp morphology. Hence, the combined application of both types of enzymes offers a high potential for upgrading pulps in order to produce a pure and high-value cellulose product. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp in Linwu ducks.

PubMed

Zhang, Xu; Li, Haobang; Jiang, Guitao; Wang, Xiangrong; Huang, Xuan; Li, Chuang; Wu, Duanqin; Dai, Qiuzhong

2018-04-11

The objective of this study was to evaluate the effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp as unusual feedstuffs in Linwu ducks. Forty ducks were assigned to each treatment group and fed diets with or without complex enzyme supplementation. All birds received the same quantity of raw material (60 g) via the force-feeding procedure. With the exception of leucine and phenylalanine, amino acid concentrations in hawthorn pulp were twice those in citrus pulp. Enzyme supplementation significantly increased apparent dry matter digestibility (ADM) of citrus pulp (P < 0.05), but had no significant effects (P > 0.05) on the apparent and true utilization rates of other nutrients, apparent metabolizable energy (AME), or true metabolizable energy (TME), from citrus pulp and hawthorn pulp by Linwu ducks. However, enzyme supplementation significantly increased (P < 0.05) apparent gross energy, true gross energy, AME, and TME of hawthorn pulp for Linwu ducks. There were no differences in the apparent and true utilization rates of amino acids from citrus pulp (P > 0.56) between the groups, with the exception of arginine (P < 0.05). There was an increasing trend in the apparent and true utilization rates of alanine (P = 0.06) and tyrosine (P = 0.074) from citrus pulp with enzyme supplementation. The apparent and true utilization rates of threonine in hawthorn pulp were increased significantly (P < 0.05) following enzyme supplementation. The addition of exogenous enzymes improved the forage quality of citrus pulp and hawthorn pulp, which represent potential feed resources for husbandry production.

Biosynthesis of gold nanoparticles using Capsicum annuum var. grossum pulp extract and its catalytic activity

NASA Astrophysics Data System (ADS)

Yuan, Chun-Gang; Huo, Can; Yu, Shuixin; Gui, Bing

2017-01-01

Biological synthesis approach has been regarded as a green, eco-friendly and cost effective method for nanoparticles preparation without any toxic solvents and hazardous bi-products during the process. This present study reported a facile and rapid biosynthesis method for gold nanoparticles (GNPs) from Capsicum annuum var. grossum pulp extract in a single-pot process. The aqueous pulp extract was used as biotic reducing agent for gold nanoparticle growing. Various shapes (triangle, hexagonal, and quasi-spherical shapes) were observed within range of 6-37 nm. The UV-Vis spectra showed surface plasmon resonance (SPR) peak for the formed GNPs at 560 nm after 10 min incubation at room temperature. The possible influences of extract amount, gold ion concentration, incubation time, reaction temperature and solution pH were evaluated to obtain the optimized synthesis conditions. The effects of the experimental factors on NPs synthesis process were also discussed. The produced gold nanoparticles were characterized by transform electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDS) and Fourier Transform infrared spectroscopy (FTIR). The results demonstrated that the as-obtained GNPs were well dispersed and stable with good catalytic activity. Biomolecules in the aqueous extract were responsible for the capping and stabilization of GNPs.

Application of thermophilic enzymes and water jet system to cassava pulp.

PubMed

Chaikaew, Siriporn; Maeno, Yuka; Visessanguan, Wonnop; Ogura, Kota; Sugino, Gaku; Lee, Seung-Hwan; Ishikawa, Kazuhiko

2012-12-01

Co-production of fermentable sugars and nanofibrillated cellulose from cassava pulp was achieved by the combination of thermophilic enzymes (endoglucanase, β-glucosidase, and α-amylase) and a new atomization system (Star Burst System; SBS), which employs opposing water jets. The SBS represents a key technology for providing cellulose nanofibers and improving the enzymatic saccharification of cassava pulp. Depending on the enzymes used, the production of glucose from cassava pulp treated with the SBS was 1.2- to 2.5-fold higher than that from pulp not treated with the SBS. Nanofibrillated cellulose with the gel-like property in suspension was produced (yield was over 90%) by α-amylase treatment, which completely released trapped starch granules from the fibrous cell wall structure of cassava pulp pretreated with the SBS. The SBS provides an environmentally low-impact pretreatment system for processing biomass material into value-added products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antioxidant properties and hyphenated HPLC-PDA-MS profiling of Chilean Pica mango fruits (Mangifera indica L. Cv. piqueño).

PubMed

Ramirez, Javier E; Zambrano, Ricardo; Sepúlveda, Beatriz; Simirgiotis, Mario J

2013-12-31

Antioxidant capacities and polyphenolic contents of two mango cultivars from northern Chile, one of them endemic of an oasis in the Atacama Desert, were compared for the first time. Twenty one phenolic compounds were detected in peel and pulp of mango fruits varieties Pica and Tommy Atkins by HPLC-PDA-MS and tentatively characterized. Eighteen compounds were present in Pica pulp (ppu), 13 in Pica peel (ppe) 11 in Tommy Atkins pulp (tpu) and 12 in Tommy Atkins peel (tpe). Three procyanidin dimers (peaks 6, 9 and 10), seven acid derivatives (peaks 1-4, 11, 20 and 21) and four xanthones were identified, mainly mangiferin (peak 12) and mangiferin gallate, (peak 7), which were present in both peel and pulp of the two studied species from northern Chile. Homomangiferin (peak 13) was also present in both fruit pulps and dimethylmangiferin (peak 14) was present only in Tommy pulp. Pica fruits showed better antioxidant capacities and higher polyphenolic content (73.76/32.23 µg/mL in the DPPH assay and 32.49/72.01 mg GAE/100 g fresh material in the TPC assay, for edible pulp and peel, respectively) than Tommy Atkins fruits (127.22/46.39 µg/mL in the DPPH assay and 25.03/72.01 mg GAE/100 g fresh material in the TPC assay for pulp and peel, respectively). The peel of Pica mangoes showed also the highest content of phenolics (66.02 mg/100 g FW) measured by HPLC-PDA. The HPLC generated fingerprint can be used to authenticate Pica mango fruits and Pica mango food products.

Influence of different types of pulp treatment during isolation in the obtention of human dental pulp stem cells

PubMed Central

Viña-Almunia, Jose; Borras, Consuelo; Gambini, Juan; El Alamy, Marya; Viña, Jose

2016-01-01

Background Different methods have been used in order to isolate dental pulp stem cells. The aim of this study was to study the effect of different types of pulp treatment during isolation, under 3% O2 conditions, in the time needed and the efficacy for obtaining dental pulp stem cells. Material and Methods One hundred and twenty dental pulps were used to isolate dental pulp stem cells treating the pulp tissue during isolation using 9 different methods, using digestive, disgregation, or mechanical agents, or combining them. The cells were positive for CD133, Oct4, Nestin, Stro-1, CD34 markers, and negative for the hematopoietic cell marker CD-45, thus confirming the presence of mesenchymal stem cells. The efficacy of dental pulp stem cells obtention and the minimum time needed to obtain such cells comparing the 9 different methods was analyzed. Results Dental pulp stem cells were obtained from 97 of the 120 pulps used in the study, i.e. 80.8% of the cases. They were obtained with all the methods used except with mechanical fragmentation of the pulp, where no enzymatic digestion was performed. The minimum time needed to isolate dental pulp stem cells was 8 hours, digesting with 2mg/ml EDTA for 10 minutes, 4mg/ml of type I collagenase, 4mg/ml of type II dispase for 40 minutes, 13ng/ml of thermolysine for 40 minutes and sonicating the culture for one minute. Conclusions Dental pulp stem cells were obtained in 97 cases from a series of 120 pulps. The time for obtaining dental pulp stem cells was reduced maximally, without compromising the obtention of the cells, by combining digestive, disgregation, and mechanical agents. Key words:Dental pulp stem cells, mesenchymal stem cells, isolation method. PMID:26946201

Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective.

PubMed

Huang, George T-J; Al-Habib, Mey; Gauthier, Philippe

2013-03-01

There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic.

Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective

PubMed Central

HUANG, GEORGE T.-J.; AL-HABIB, MEY; GAUTHIER, PHILIPPE

2013-01-01

There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic. PMID:23914150

Biogas generation apple pulp.

PubMed

Llaneza Coalla, H; Blanco Fernández, J M; Morís Morán, M A; López Bobo, M R

2009-09-01

In view of the pressing problem that appears in our region (Asturias, north of Spain) with the residues from the cider production, it was decided to test this kind of material as a co-substrate joint with slaughterhouse waste in a laboratory unit. The anaerobic digestion of apple pulp was investigated for biogas production. This paper presents the results where apple pulp was co-digested with slaughterhouse waste (pig intestine and bovine stomach content) in a biogas laboratory unit (10 l CSTR reactor). The production of biogas has reached very satisfactory values during the whole test (0.8m(3)kg(-1)OTS), verifying that the process is kept in stable conditions of pH (near 8.0), and the volatile fatty acids was always underneath 3000 mg/l, when the pulp amount was lower than 100g in mesophilic conditions. The fat concentration into the digester remained always below the value that causes inhibition of the methanogenic bacteria, 500 mg/l. Finally, methane concentration (77-80%) and H(2)S concentration (400 ppm) in the biogas, they were similar to those obtained when the test was run out in the absence of apple pulp. The process efficiency with respect to COD removal was high, near 80% of the total COD. Finally, inhibitory effects of methanogenic bacteria were observed when pulp concentration was around 10% in the input material.

Thermal Scanning of Dental Pulp Chamber by Thermocouple System and Infrared Camera during Photo Curing of Resin Composites

PubMed Central

Hamze, Faeze; Ganjalikhan Nasab, Seyed Abdolreza; Eskandarizadeh, Ali; Shahravan, Arash; Akhavan Fard, Fatemeh; Sinaee, Neda

2018-01-01

Introduction: Due to thermal hazard during composite restorations, this study was designed to scan the pulp temperature by thermocouple and infrared camera during photo polymerizing different composites. Methods and Materials: A mesio-occlso-distal (MOD) cavity was prepared in an extracted tooth and the K-type thermocouple was fixed in its pulp chamber. Subsequently, 1 mm increment of each composites were inserted (four composite types were incorporated) and photo polymerized employing either LED or QTH systems for 60 sec while the temperature was recorded with 10 sec intervals. Ultimately, the same tooth was hemisected bucco-lingually and the amalgam was removed. The same composite curing procedure was repeated while the thermogram was recorded using an infrared camera. Thereafter, the data was analyzed by repeated measured ANOVA followed by Tukey’s HSD Post Hoc test for multiple comparisons (α=0.05). Results: The pulp temperature was significantly increased (repeated measures) during photo polymerization (P=0.000) while there was no significant difference among the results recorded by thermocouple comparing to infrared camera (P>0.05). Moreover, different composite materials and LCUs lead to similar outcomes (P>0.05). Conclusion: Although various composites have significant different chemical compositions, they lead to similar pulp thermal changes. Moreover, both the infrared camera and the thermocouple would record parallel results of dental pulp temperature. PMID:29707014

Use of photoactivated disinfection and platelet-rich fibrin in regenerative Endodontics

PubMed Central

Johns, Dexton Antony; Shivashankar, Vasundara Yayathi; Krishnamma, Shoba; Johns, Manu

2014-01-01

Aim: Photoactivated disinfection has been used as an adjunct to conventional endodontic treatment. Its use in regenerative endodontics is not reported in literature. The aim of this case report was to describe a new proposal for pulp revascularization with disinfection of pulp canal space using a unique combination of a photosensitizer solution and low-power laser light. Materials and Methods: A 9-year-old boy came with the chief complaint of discolored upper central incisors (#8, #9). A diagnosis of pulp necrosis was made on the basis of clinical and radiographic findings. The canal was irrigated with 5.25% sodium hypochlorite solution and dried with paper points. Photodynamic therapy was used to disinfect the root canal and platelet-rich fibrin was used to revitalize the pulp. Three millimeters of gray mineral trioxide aggregate was placed directly over the platelet-rich plasma clot. Three days later, the tooth was double-sealed with permanent filling materials. Results: Clinical examination revealed no sensitivity to percussion or palpation tests. Radiograph revealed continued thickening of the dentinal walls, root lengthening, regression of the peri-apical lesion and apical closure. Both the roots showed complete apical closure at the 10-month follow-up. However, the teeth were not responsive to electric pulp test. Conclusion: This report of pulp revascularization shows that disinfection with photodynamic therapy combined with platelet-rich fibrin leads to satisfactory root development in necrotic immature teeth. PMID:25298655

A multi-criteria decision analysis of management alternatives for anaerobically digested kraft pulp mill sludge

PubMed Central

Eikelboom, Martijn; Lopes, Alice do Carmo Precci; Silva, Claudio Mudadu; Rodrigues, Fábio de Ávila; Zanuncio, José Cola

2018-01-01

The Multi-Criteria Decision Analysis (MCDA) procedure was used to compare waste management options for kraft pulp mill sludge following its anaerobic digestion. Anaerobic digestion of sludge is advantageous because it produces biogas that may be used to generate electricity, heat and biofuels. However, adequate management of the digested sludge is essential. Landfill disposal is a non-sustainable waste management alternative. Kraft pulp mill digested sludge applied to land may pose risks to the environment and public health if the sludge has not been properly treated. This study is aimed to compare several recycling alternatives for anaerobically digested sludge from kraft pulp mills: land application, landfill disposal, composting, incineration, pyrolysis/gasification, and biofuel production by algae. The MCDA procedure considered nine criteria into three domains to compare digested sludge recycling alternatives in a kraft pulp mill: environmental (CO2 emission, exposure to pathogens, risk of pollution, material and energy recovery), economic (overall costs, value of products) and technical (maintenance and operation, feasibility of implementation). The most suitable management options for digested sludge from kraft pulp mills were found to be composting and incineration (when the latter was coupled with recycling ash to the cement industry). Landfill disposal was the worst option, presenting low performance in feasibility of implementation, risk of pollution, material and energy recovery. PMID:29298296

Active capping technology: a new environmental remediation of contaminated sediment.

PubMed

Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

2016-03-01

The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented.

Selected Translations on East European Foreign Trade, No. 5.

DTIC Science & Technology

1961-08-31

eggs, cereals, oil -yielding seeds , and pulped fruit represented 2/3 of all exports. At the same time, unprocessed agricultural products [sic...prefer these raw materials, mainly grain, livestock for meat, and scarce oil - seeds , but show very little interest in, for instance, fruit pulps, which in...mineral materials, and metals. This is because the quantities of oil derivatives and cast iron are increased, and coal and iron ore from the Donets

Influence of moderate to severe chronic periodontitis on dental pulp

PubMed Central

Fatemi, K; Disfani, R; Zare, R; Moeintaghavi, A; Ali, Saadat A.; Boostani, H. R

2012-01-01

Background: The relationship between periodontal disease and dental pulp changes is controversial and has been debated for many years. This human study was performed to evaluate the possible effects of moderate to advanced periodontal disease on the different aspect of dental pulp structure. Materials and Methods: Twenty hopeless permanent teeth were extracted from systemically healthy adults because of moderate to advanced chronic periodontitis, with a bone loss of >6 mm and a mobility of grade 2 or 3. Upon extraction, the apical 2 to 3 mm of the roots were immediately sectioned. Four to five sections were mounted on each slide, and every third slide was stained with hematoxylin and eosin. The specimens were histologically processed and examined by an oral pathologist. Results: Non-inflamed pulp, with partial or complete necrosis in some sections and several non-necrotic sections, was found in only 6.3% of teeth. Most teeth (58.3%) displayed edematous pulps. Slightly fibrotic pulps were seen in 52.1% of sections. Odontoblastic integrity was seen in 31.3% of teeth. Most teeth (77.1%) displayed no pulp stones. In 43.8% of teeth, the pulp vessels displayed dilatation. Conclusions: Moderate to advanced periodontal disease can affect the dental pulp. Careful consideration of diagnostic and treatment planing in patients with endodontic-periodontal involvement is therefore recommended. PMID:23493524

Dental Pulp Defence and Repair Mechanisms in Dental Caries

PubMed Central

Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J.; Cooper, Paul R.

2015-01-01

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo. PMID:26538821

Dental Pulp Defence and Repair Mechanisms in Dental Caries.

PubMed

Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J; Cooper, Paul R

2015-01-01

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Human treated dentin matrices combined with Zn-doped, Mg-based bioceramic scaffolds and human dental pulp stem cells towards targeted dentin regeneration.

PubMed

Bakopoulou, Athina; Papachristou, Eleni; Bousnaki, Maria; Hadjichristou, Christina; Kontonasaki, Eleana; Theocharidou, Anna; Papadopoulou, Lambrini; Kantiranis, Nikolaos; Zachariadis, George; Leyhausen, Gabriele; Geurtsen, Werner; Koidis, Petros

2016-08-01

This study aimed to investigate the potential of Mg-based bioceramic scaffolds combined with human treated-dentin matrices (hTDMs) and dentinogenesis-related morphogens to promote odontogenic differentiation and dentin-like tissue formation by Dental Pulp Stem Cells-DPSCs. DPSC cultures were established and characterized by flow cytometry. Experimental cavities were prepared inside crowns of extracted teeth and demineralized by EDTA (hTDMs). Zn-doped, Mg-based bioceramic scaffolds, synthesized by the sol-gel technique, were hosted inside the hTDMs. DPSCs were spotted inside the hTDMs/scaffold constructs with/without additional exposure to DMP-1 or BMP-2 (100ng/ml, 24h). Scanning Electron Microscopy-SEM, live/dead fluorescence staining and MTT assay were used to evaluate cell attachment and viability; Real time PCR for expression of osteo/odontogenic markers; Inductively Coupled Plasma-Atomic Emission Spectrometry-ICP/AES for scaffold elemental release analysis; ELISA for hTDM growth factor release analysis; SEM and X-ray Diffraction-XRD for structural/chemical characterization of the regenerated tissues. Scaffolds constantly released low concentrations of Mg(2+), Ca(2+), Zn(2+) and Si(4+), while hTDMs growth factors, like DMP-1, BMP-2 and TGFβ-1. hTDMs/scaffold constructs supported DPSC viability, inducing their rapid odontogenic shift, indicated by upregulation of DSPP, BMP-2, osteocalcin and osterix expression. Newly-formed Ca-P tissue overspread the scaffolds partially transforming into bioapatite. Exposure to DMP-1 or BMP-2 pronouncedly enhanced odontogenic differentiation phenomena. This is the first study to validate that combining the bioactivity and ion releasing properties of bioceramic materials with growth factor release by treated natural dentin further supported by exogenous addition of key dentinogenesis-related morphogens (DMP-1, BMP-2) can be a promising strategy for targeted dentin regeneration. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Idiopathic dental pulp calcifications in a tertiary care setting in South India

PubMed Central

Satheeshkumar, PS; Mohan, Minu P; Saji, Sweta; Sadanandan, Sudheesh; George, Giju

2013-01-01

Background: Dental pulp calcifications are unique and represent the dental pulp regenerative process. Dental pulp calcifications are sometimes routine findings in oral radiographs and may later serve as an important diagnostic criterion for a hidden aspect of systemic illness. Objective: The purpose of this study was to assess the patterns and prevalence of idiopathic dental pulp calcifications in a tertiary care setting in South India. Materials and Methods: A total of 227 patients were included in the study fulfilling the inclusion criteria. Age range of the study population was from 15 to 70 years. Teeth were examined under digital panoramic radiograph. The presence or absence of pulp stones was recorded. The presence of pulp stone were categorized according to the types classified as Type I, Type IA, Type II, Type IIA, Type II B, and Type III. The frequency of occurrence of pulp stones with sex, tooth type, dental arches, and types were compared with the types of calcification. Results: Total no. of patients with pulpal calcification were 227 [females 133 (58.59%) and males 94 (41.40%)]. The most common type between both sexes was Type I (48%). Total no. of teeth with calcification was 697; maxilla (48%), mandible (52%). The prevalence of pulp stone was found to be higher in the molars in both the arches. Most no. of pulp stones are reported at the third and fourth decade of life. Conclusion: Idiopathic dental pulp calcifications are incidental radiographic findings of the pulp tissue and also may be an indicator of underlying disease. PMID:23349577

Production and bioactivity of pectic oligosaccharides from fruit and vegetable biomass

USDA-ARS?s Scientific Manuscript database

Pectin is abundant in various agro-industrial bio-resources such as citrus peel, apple pomace, cranberry pulp and sugar beet pulp. These materials can therefore be considered as a source of potential bioactive pectic oligosaccharides. This chapter reviews the various extraction and purification meth...

Preparation and properties of water and glycerol-plasticized sugar beet pulp plastics

USDA-ARS?s Scientific Manuscript database

Sugar beet pulp (SBP), the residue from sugar extraction, was compounded and turned into thermoplastic composite materials. The compounding was performed using a common twin screw compounding extruder and water and glycerol were used as plasticizers. The plasticization of SBP utilized the water-solu...

In-situ Subaqueous Capping of Mercury-Contaminated Sediments in a Fresh-Water Aquatic System, Part II-Evaluation of Sorption Materials

EPA Science Inventory

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate...

Cytotoxicity Testing of Temporary Luting Cements with Two- and Three-Dimensional Cultures of Bovine Dental Pulp-Derived Cells

PubMed Central

Ülker, Hayriye Esra; Ülker, Mustafa; Gümüş, Hasan Önder; Yalçın, Muhammet; Şengün, Abdulkadir

2013-01-01

This study evaluated the cytotoxicity of eugenol-containing and eugenol-free temporary luting cements. For cytotoxicity testing, bovine pulp-derived cells transfected with Simian virus 40 Large T antigen were exposed to extracts of eugenol-containing (Rely X Temp E) and eugenol-free (Provicol, PreVISION CEM, and Rely X Temp NE) temporary luting cements for 24 h. The cytotoxicity of the same materials was also evaluated in a dentin barrier test device using three-dimensional cell cultures of bovine pulp-derived cells. The results of the cytotoxicity studies with two-dimensional cultures of bovine dental pulp-derived cells revealed that cell survival with the extracts of Rely X Temp E, Provicol, PreVISION CEM, and Rely X Temp NE was 89.1%, 84.9%, 92.3%, and 66.8%, respectively. Rely X Temp NE and Provicol showed cytotoxic effects on bovine dental pulp-derived cells (P < 0.05). The results of the dentin barrier test revealed that cell survival with the above-mentioned temporary cement was 101.5%, 91.9%, 93.5%, and 90.6%, respectively. None of the temporary luting cements significantly reduced cell survival compared with the negative control in the dentin barrier test (P > 0.05). Biologically active materials released from temporary luting cements may not influence the dentine-pulp complex if the residual dentine layer is at least 0.5 mm thick. PMID:23984419

Correlation between Histological Status of the Pulp and Its Response to Sensibility Tests

PubMed Central

Naseri, Mandana; Khayat, Akbar; Zamaheni, Sara; Shojaeian, Shiva

2017-01-01

Introduction: The purpose of this study was to assess the accuracy of sensibility tests by correlating it with histologic pulp condition. Methods and Materials: Assessment of clinical signs and symptoms were performed on 65 permanent teeth that were scheduled to be extracted for periodontal, prosthodontic or orthodontic reasons. The normal pulp and reversible pulpitis were considered as treatable tooth conditions while irreversible pulpitis and necrosis were considered as untreatable conditions. The teeth were then extracted and sectioned for histological analysis of dental pulp. Histologic status and classification corresponded to the treatable or untreatable pulp condition. Comparisons between histological treatable and untreatable pulp condition were performed with chi-square analysis for sensibility test responses. The positive predictive value (PPV), negative predictive value (NPV) and accuracy to detect untreatable from treatable pulp condition were calculated for each test. Results: A significant difference was detected in the normal and a sharp lingered response to heat and cold tests. There was significant difference in the negative response to EPT between histological groups. The kappa agreement coefficient between clinical and histological diagnosis of pulp condition was about 0.843 (P<0.001). The accuracy of cold and heat tests and EPT to detect treatable pulp or untreatable pulp states were 78, 74 and 62%, respectively. The sensibility tests diagnosed untreatable pulpitis with a higher probability (NPV=63%-67% -54%, PPV=83%-91% -95% for heat, cold and EPT, respectively). Conclusion: Sensibility test results were more likely to diagnose pulpal disease or untreatable pulp conditions. However, to increase the diagnostic accuracy patient history, clinical signs and symptoms and also radiographic findings in conjunction with sensibility tests must be used. The result of this small study demonstrated a good agreement between clinical and histological pulp diagnosis. PMID:28179918

Determination of ABO blood grouping and Rhesus factor from tooth material

PubMed Central

Kumar, Pooja Vijay; Vanishree, M; Anila, K; Hunasgi, Santosh; Suryadevra, Sri Sujan; Kardalkar, Swetha

2016-01-01

Objective: The aim of the study was to determine blood groups and Rhesus factor from dentin and pulp using absorption-elution (AE) technique in different time periods at 0, 3, 6, 9 and 12 months, respectively. Materials and Methods: A total of 150 cases, 30 patients each at 0, 3, 6, 9 and 12 months were included in the study. The samples consisted of males and females with age ranging 13–60 years. Patient's blood group was checked and was considered as “control.” The dentin and pulp of extracted teeth were tested for the presence of ABO/Rh antigen, at respective time periods by AE technique. Statistical Analysis: Data were analyzed in proportion. For comparison, Chi-square test or Fisher's exact test was used for the small sample. Results: Blood group antigens of ABO and Rh factor were detected in dentin and pulp up to 12 months. For both ABO and Rh factor, dentin and pulp showed 100% sensitivity for the samples tested at 0 month and showed a gradual decrease in the sensitivity as time period increased. The sensitivity of pulp was better than dentin for both the blood grouping systems and ABO blood group antigens were better detected than Rh antigens. Conclusion: In dentin and pulp, the antigens of ABO and Rh factor were detected up to 12 months but showed a progressive decrease in the antigenicity as the time period increased. When compared the results obtained of dentin and pulp in ABO and Rh factor grouping showed similar results with no statistical significance. The sensitivity of ABO blood grouping was better than Rh factor blood grouping and showed a statistically significant result. PMID:27721625

Histological Evaluation of Allium sativum Oil as a New Medicament for Pulp Treatment of Permanent Teeth.

PubMed

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2015-02-01

The objective of this study was to evaluate the histo pathology effects of two medicaments Allium sativum oil and formocresol on the remaining pulp tissue of the permanent teething children. A total of 18 premolars were included in this study. Two sound premolars were extracted and subjected to histological examination to show the normal pulp tissue. Pulpo tomy procedure was performed in the rest of the remaining 16 premolars; half of them using Allium sativum oil and the rest of the tested premolars were medicated using formocresol and all were sealed with suitable restoration. Then, premolars extracted at variable intervals (48 hours, 2 weeks, 1 month, 2 months), stained using hemotoxylin and eosin etain (H&E) and prepared for histopathology examination. Histological evaluation seemed far more promising for Allium sativum oil than formocresol. Histological evaluation revealed that teeth treated with Allium sativa oil showed infammatory changes that had been resolved in the end of the study. On the contrary, the severe chronic infammation of pulp tissue accompanied with formocresol eventually produced pulp necrosis with or without fibrosis. In addition, pulp calcification was evidenced in certain cases. Allium sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning.

Histological Evaluation of the Effect of Platelet-rich Plasma on Pulp Regeneration in Nonvital Open Apex Teeth: An Animal Study.

PubMed

Ghoddusi, Jamileh; Maghsudlu, Amir; Jafarzadeh, Hamid; Jafarian, Amirhossein; Forghani, Maryam

2017-11-01

Platelet-rich plasma (PRP), which is a concentration of growth factors found in platelets, may be a suitable material for pulp regeneration. The aim of this animal study was a histological evaluation of PRP on pulp regeneration in nonvital teeth with immature apices. A total of 40 premolar dogs' teeth were chosen for this study. After general anesthesia, the teeth were exposed, and subsequently, pulps were removed and the cavities were opened to the oral cavity. After 2 weeks, root canals were irrigated and disinfected with sodium hypochlorite with noninstrumentation technique, and triple antibiotic paste was placed inside the canals. Cavities were sealed with a temporary restoration. About 4 weeks later, canals were irrigated again and the teeth were randomly divided into three groups. Bleeding was evoked with overinstrumentation, then experimental materials for each group [PRP, mineral trioxide aggregate (MTA), and parafilm respectively] were placed over the bleeding, and orifices were sealed with MTA and glass ionomer. After 3 months, dogs were sacrificed and the teeth were separated from the jaws and sections prepared for histological evaluation. Regeneration was shown in 44.7% of the samples. About 47.3% of the samples in the MTA group and 42.1% of the samples in the PRP group showed regeneration; however, no regeneration was observed in the parafilm group. Chi-square test showed no significant difference between groups I and II. The soft regenerative tissue included pulp-like tissue and vessels. Mineralized regenerative tissue included cementum-like, periodontal ligament-like, and bone-like tissues. No normal pulp and nerve tissue were observed. Both PRP and MTA may be ideal scaffolds to accelerate the regeneration process. Pulp repair in immature permanent teeth with weak roots has a better outcome than replacement of the pulp with gutta-percha or biomaterials.

Role of high molecular mass organics in colour formation during biological treatment of pulp and paper wastewater.

PubMed

Milestone, C B; Stuthridge, T R; Fulthorpe, R R

2007-01-01

This paper forms part of series of biological treatment colour behaviour studies. Surveys across a range of mills have observed colour increases in aerated stabilisation basins of 20-45%. Much of the colour formation has been demonstrated to occur in high molecular mass effluent organic constituents (HMM) present in bleach plant effluents. Removing material greater than 3000 Da essentially eliminated the colour forming ability in both E and D stage wastewaters. We have also shown that pulp and paper sludges contain anaerobic bacteria capable of reducing humic like materials. Colour formation was correlated to the anoxic conditions and the availability of readily biodegradable organic constituents during the wastewater treatment process. Overall, these studies suggest that colour formation in pulp and paper biological treatment systems may be caused by anaerobic bacteria using HMM material from the bleaching effluents as an electron acceptor for growth. This leads to the reduction of the material, which in turn leads to non-reversible internal changes, such as intra-molecular polymerisation or formation of chromophoric functional groups.

Effect of packaging materials on shelf life and quality of banana cultivars (Musa spp.).

PubMed

Hailu, M; Seyoum Workneh, T; Belew, D

2014-11-01

This study was carried out to evaluate the effect of packaging materials on the shelf life of three banana cultivars. Four packaging materials, namely, perforated low density polyethylene bag, perforated high density polyethylene bag, dried banana leaf, teff straw and no packaging materials (control) were used with three banana cultivars, locally known as, Poyo, Giant Cavendish and Williams I. The experiment was carried out in Randomized Complete Block Design in a factorial combination with three replications. Physical parameters including weight loss, peel colour, peel thickness, pulp thickness, pulp to peel ratio, pulp firmness, pulp dry matter, decay, loss percent of marketability were assessed every 3 days. Banana remained marketable for 36 days in the high density polyethylene and low density polyethylene bags, and for 18 days in banana leaf and teff straw packaging treatments. Unpackaged fruits remained marketable for 15 days only. Fruits that were not packaged lost their weight by 24.0 % whereas fruits packaged in banana leaf and teff straw became unmarketable with final weight loss of 19.8 % and 20.9 %, respectively. Packaged fruits remained well until 36th days of storage with final weight loss of only 8.2 % and 9.20 %, respectively. Starting from green mature stage, the colour of the banana peel changed to yellow and this process was found to be fast for unpackaged fruits. Packaging maintained the peel and the pulp thickness, firmness, dry matter and pulp to peel ratio was kept lower. Decay loss for unpackaged banana fruits was16 % at the end of date 15, whereas the decay loss of fruits packaged using high density and low density polyethylene bags were 43.0 % and 41.2 %, respectively at the end of the 36th day of the experiment. It can, thus, be concluded that packaging of banana fruits in high density and low density polyethylene bags resulted in longer shelf life and improved quality of the produce followed by packaging in dried banana leaf and teff straw.

Active Nanomaterials to Meet the Challenge of Dental Pulp Regeneration

PubMed Central

Keller, Laetitia; Offner, Damien; Schwinté, Pascale; Morand, David; Wagner, Quentin; Gros, Catherine; Bornert, Fabien; Bahi, Sophie; Musset, Anne-Marie; Benkirane-Jessel, Nadia; Fioretti, Florence

2015-01-01

The vitality of the pulp is fundamental to the functional life of the tooth. For this aim, active and living biomaterials are required to avoid the current drastic treatment, which is the removal of all the cellular and molecular content regardless of its regenerative potential. The regeneration of the pulp tissue is the dream of many generations of dental surgeons and will revolutionize clinical practices. Recently, the potential of the regenerative medicine field suggests that it would be possible to achieve such complex regeneration. Indeed, three crucial steps are needed: the control of infection and inflammation and the regeneration of lost pulp tissues. For regenerative medicine, in particular for dental pulp regeneration, the use of nano-structured biomaterials becomes decisive. Nano-designed materials allow the concentration of many different functions in a small volume, the increase in the quality of targeting, as well as the control of cost and delivery of active molecules. Nanomaterials based on extracellular mimetic nanostructure and functionalized with multi-active therapeutics appear essential to reverse infection and inflammation and concomitantly to orchestrate pulp cell colonization and differentiation. This novel generation of nanomaterials seems very promising to meet the challenge of the complex dental pulp regeneration. PMID:28793649

Isolation of tooth pulp cells for sex chromatin studies in experimental dehydrated and cremated remains.

PubMed

Duffy, J B; Waterfield, J D; Skinner, M F

1991-03-01

In experiments designed to assess sex chromatin in artificially mummified and heated pulp tissue, a method was devised that successfully separates cells while minimizing nuclear damage. Sex chromatin (both Barr bodies and F-bodies) is shown to preserve in dehydrated human pulps up to one year. Human pulp tissue retains sex diagnostic characteristics when heated to 100 degrees C for up to 1 h. Parallel experiments on extracted teeth from young pigs reveals comparable tissue preservation. Heat penetration is retarded, however, in unextracted pig teeth in fleshed jaws such that temperatures could be raised to 300 degrees C for longer than 1 h. Heat penetration into fleshed material was further tested by the insertion of thermocouple probes to assess the temperature attained within the pulp chamber. At chamber temperatures up to 75 degrees C sex diagnosis in human pulps from extracted teeth was still possible. In outdoor incineration of fleshed pigs' heads in an open fire, 75 degrees C in the pulp chamber was reached at a fire temperature within the range 500-700 degrees C. The implications of these findings for forensic situations are described.

DENTAL PULP TISSUE ENGINEERING

PubMed Central

Demarco, FF; Conde, MCM; Cavalcanti, B; Casagrande, L; Sakai, V; Nör, JE

2013-01-01

Dental pulp is a highly specialized mesenchymal tissue, which have a restrict regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp-space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article will review the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and providing insightful information to readers about the different aspects enrolled in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The finds collected in our review showed that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable and the next decade will certainly be an exciting time for dental and craniofacial research. PMID:21519641

Pulp revascularization of immature permanent teeth: a review of the literature and a proposal of a new clinical protocol.

PubMed

Namour, Mélanie; Theys, Stephanie

2014-01-01

Tissue engineering is a growing field. In the near future, it will probably be possible to generate a complete vital tooth from a single stem cell. Pulp revascularization is dependent on the ability of residual pulp and apical and periodontal stem cells to differentiate. These cells have the ability to generate a highly vascularized and a conjunctive rich living tissue. This one is able to colonize the available pulp space. Revascularization is a new treatment method for immature necrotic permanent teeth. Up to now, apexification procedures were applied for these teeth, using calcium dihydroxide or MTA to produce an artificial apical barrier. However, the pulp revascularization allows the stimulation of the apical development and the root maturation of immature teeth. Two pulp revascularization techniques are used in the literature, one using calcium dihydroxide and the second using a triple antibiotic paste. Based on these two different pulp revascularization protocols, which obtain the desired therapeutic success, the literature will be reviewed and analyzed according to the relevance of their choice of materials. Based on the literature, we propose a new relevant protocol and a new mixture of antibiotics.

Incorporating biopulping technology into wood yard operations

Treesearch

Gary M. Scott; Eric Horn; Masood Akhtar; Ross E. Swaney; Michael J. Lentz; David F. Shipley

1998-01-01

Biopulping is the treatment of wood chips and other lignocellulosic materials with lignin-degrading fungi prior to pulping. Ten years of industry-sponsored research has demonstrated the technical feasibility of the technology for mechanical pulping at a laboratory scale. Two 50-ton outdoor chip pile trials recently conducted at the USDA Forest Service, Forest Products...

Dentin barrier test with transfected bovine pulp-derived cells.

PubMed

Schmalz, G; Schuster, U; Thonemann, B; Barth, M; Esterbauer, S

2001-02-01

Growth kinetics of SV40 large T-antigen-transfected bovine pulp-derived cells on dentin were investigated. These cells were used in a dentin barrier test device, and the system was evaluated by testing a set of dental filling materials. Cells (120 cells/mm2) were seeded on dentin slices and incubated for up to 21 days. Cell proliferation was recorded using MTT assay. For cytotoxicity tests 3500 cells/mm2 were seeded on dentin discs, which were then incorporated into the dentin barrier test device. After 72 h preincubation test materials were applied. After a 24 h exposure with or without perfusion of the pulpal part of the test device, cell survival was evaluated using MTT assay. The cells revealed similar growth kinetics on dentin slices and on tissue culture plates. In cytotoxicity tests the cells were more sensitive toward the test materials than previously used three-dimensional cultures of human foreskin fibroblasts and as anticipated from clinical experience. Further improvement is expected by using three-dimensional cultures of pulp-derived cells.

Rheology of lyocell solutions from different cellulosic sources and development of regenerated cellulosic microfibers

NASA Astrophysics Data System (ADS)

Li, Zuopan

2003-10-01

The primary goals of the study were to develop manufactured cellulosic fibers and microfibers from wood pulps as well as from lignocellulosic agricultural by-products and to investigate alternative cellulosic sources as raw materials for lyocell solutions. A protocol was developed for the lyocell preparation from different cellulose sources. The cellulose sources included commercial dissolving pulps, commercial bleached hardwood, unbleached hardwood, bleached softwood, unbleached softwood, bleached thermomechanical pulp, unbleached thermomechanical pulp, bleached recycled newsprint, unbleached recycled newsprint, bagasse and kudzu. The rheological behavior of solutions was characterized. Complex viscosities and effective elongational viscosities were measured and the influences of parameters such as cellulose source, concentration, bleaching, and temperature were studied. One-way ANOVA post hoc tests were carried out to identify which cellulose sources have the potential to produce lyocell solutions having similar complex viscosities to those from commercial dissolving pulps. Lyocell solutions from both bleached and unbleached softwood and hardwood were classified as one homogenous subset that had the lowest complex viscosity. Kudzu solutions had the highest complex viscosity. The results showed the potential to substitute DP 1457 dissolving pulp with unbleached recycled newsprint pulps, to substitute DP 1195 dissolving pulp with bleached and unbleached thermomechanical pulps, to substitute DP 932 dissolving pulp with bleached thermomechanical pulps or bleached recycled newsprint pulps, to substitute DP 670 dissolving pulp with bagasse. Lyocell fibers were produced from selected solutions and were treated to produce microfibers. Water, sulfuric acid solutions and sodium hydroxide solutions were used. The treatment of lyocell fibers in 17.5% NaOH solutions for five minutes at 20°C successfully broke the fibers into fibrils along fiber axis. The diameters of the fibrils were generally in the range of 2 to 6 mum, and there were also finer fibrils with diameters less than 1 mum.

Approaches to New Endcaps for Improved Oxidation Resistance

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B.; Frimer, Aryeh A.

1999-01-01

Norbornenyl-end capped PMR polyimide resins are widely used as polymer matrix composite materials for aircraft engine applications, since they combine ease of processing with good oxidative stability up to 300 C. PMR resins are prepared by a two-step approach involving the initial formation of oligomeric pre-polymers capped at both ends by a latent reactive end cap. The end cap undergoes cross-linking during higher temperature processing, producing the desired low density, high specific strength materials, for PMR- 15. The end cap facilitates processing by controlling the molecular weight of the oligomer and allowing flow before it cross-links. However, after cross-linking, this very end cap accounts for much of the weight loss in the polymer on aging in air at elevated temperatures. Understanding this degradation provides clues for designing new end caps to slow down degradation, and prolong the lifetime of the material.

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications.

PubMed

Eliaz, Noam; Metoki, Noah

2017-03-24

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs.

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications

PubMed Central

Eliaz, Noam; Metoki, Noah

2017-01-01

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs. PMID:28772697

Know your fibers : process and properties, or, a material science approach to designing pulp molded products

Treesearch

John F. Hunt

1998-01-01

The following results are preliminary, but show some basic information that will be used in an attempt to model pulp molded structures so that by measuring several basic fundamental properties of a fiber furnish and specifying process conditions, a molded structure could be designed for a particular performance need.

Using a fully recyclable dicarboxylic acid for producing dispersible and thermally stable cellulose nanomaterials from different cellulosic sources

Treesearch

Chao Jia; Liheng Chen; Ziqiang Shao; Umesh P. Agarwal; Liangbing Hu; J. Y. Zhu

2017-01-01

We fabricated cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) from different cellulose materials (bleached eucalyptus pulp (BEP), spruce dissolving pulp (SDP) and cotton based qualitative filter paper (QFP) using concentrated oxalic acid hydrolysis and subsequent mechanical fibrillation (for CNFs). The process was green as acid can easily be recovered,...

Stuck fuel rod capping sleeve

DOEpatents

Gorscak, Donald A.; Maringo, John J.; Nilsen, Roy J.

1988-01-01

A stuck fuel rod capping sleeve to be used during derodding of spent fuel assemblies if a fuel rod becomes stuck in a partially withdrawn position and, thus, has to be severed. The capping sleeve has an inner sleeve made of a lower work hardening highly ductile material (e.g., Inconel 600) and an outer sleeve made of a moderately ductile material (e.g., 304 stainless steel). The inner sleeve may be made of an epoxy filler. The capping sleeve is placed on a fuel rod which is then severed by using a bolt cutter device. Upon cutting, the capping sleeve deforms in such a manner as to prevent the gross release of radioactive fuel material

Tribological study of non-asbestos fiber reinforced phenolic composites for braking applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gopal, P.; Dharani, L.R.; Blum, F.D.

A cashew modified phenolic resin was used as the binder to prepare several different nonasbestos fiber reinforced composite friction materials. Friction-wear tests were conducted at various loads, speeds and temperatures on a Chase friction testing machine. The fade and wear characteristics of glass and carbon fiber reinforced friction materials were studied. The wear rates of hybrid composites containing Kevlar{reg_sign} (registered trademark of E.I. duPont de Nemours) pulp were compared to those of control composites without Kevlar{reg_sign} pulp.

Coexistence Possibility of Biomass Industries

NASA Astrophysics Data System (ADS)

Jingchun, Sun; Junhu, Hou

This research aims to shed light on the mechanism of agricultural biomass material competition between the power generation and straw pulp industries and the impact on their coexistence. A two-stage game model is established to analyze including factors such as unit transportation cost, and profit spaces for the firms. The participants in the competition are a biomass supplier, a power plant and a straw pulp plant. From the industrial economics perspective, our analysis shows that raw material competition will bring about low coexistence possibility of the two industries based on agricultural residues in a circular collection area.

Effects of Growth Factors on Dental Stem/ProgenitorCells

PubMed Central

Kim, Sahng G.; Solomon, Charles; Zheng, Ying; Suzuki, Takahiro; Mo, Chen; Song, Songhee; Jiang, Nan; Cho, Shoko; Zhou, Jian; Mao, Jeremy J.

2014-01-01

Synopsis The primary goal of regenerative endodontics is to restore the vitality and functions of the dentin-pulp complex, as opposed to filing of the root canal with bioinert materials. Structural restoration is also important but is likely secondary to vitality and functions. Myriads growth factors regulate multiple cellular functions including migration, proliferation, differentiation and apoptosis of several cell types that are intimately involved in dentin-pulp regeneration: odontoblasts, interstitial fibroblasts, vascular-endothelial cells and sprouting nerve fibers. Recent work showing that growth factor delivery, without cell transplantation, can yield pulp-dentin like tissues in vivo provides one of the tangible pathways for regenerative endodontics. This review synthesizes our knowledge on a multitude of growth factors that are known or anticipated to be efficacious in dental pulp-dentin regeneration. PMID:22835538

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide

PubMed Central

Peimani, Ali; Asgary, Saeed

2013-01-01

Objectives The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement. Materials and Methods A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation. Results All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples. Conclusions This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable. PMID:24303358

Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products.

PubMed

Kavitha Sankar, P C; Ramakrishnan, Reshmi; Rosemary, M J

2016-04-01

Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy of Sex Determination from Human Dental Pulp Tissue and its Reliability as a Tool in Forensic Dentistry

PubMed Central

Khanna, Kaveri Surya

2015-01-01

Background: Sex determination is one of the primary steps in forensics. Barr body can be used as a histological method for identification of sex as it is found to be specific to female somatic cells and rare in male cells. To demarcate human dental pulp as an important identification tool of sex in forensic odontology (FO) and to evaluate the time period till which sex can be determined from pulp tissue using three stains H and E, Feulgen, and acridine - orange under fluorescence so as. Materials and Methods: 90 pulp samples (45 males and 45 females) were subjected to Barr body analysis for determination of sex using light and fluorescent microscopy. Results: Barr body was found to be positive for female samples and negative or rare in the male sample (<3%). Conclusion: Barr body from human dental pulp tissue can be used as a successful determinant of sex identification in FO. PMID:26668474

Wind blade spar cap and method of making

DOEpatents

Mohamed, Mansour H [Raleigh, NC

2008-05-27

A wind blade spar cap for strengthening a wind blade including an integral, unitary three-dimensional woven material having a first end and a second end, corresponding to a root end of the blade and a tip end of the blade, wherein the material tapers in width from the first to the second end while maintaining a constant thickness and decreasing weight therebetween, the cap being capable of being affixed to the blade for providing increased strength with controlled variation in weight from the root end to the tip end based upon the tapered width of the material thereof. The present inventions also include the method of making the wind blade spar cap and a wind blade including the wind blade spar cap.

Cytotoxicity Evaluation of Self Adhesive Composite Resin Cements by Dentin Barrier Test on 3D Pulp Cells.

PubMed

Ulker, Hayriye Esra; Sengun, Abdulkadir

2009-04-01

The aim of this study was to evaluate the effects of five self-etch dental composite resin cements on the cell viability of bovine dental papilla-derived cells. The cytotoxicity of composite resin cements (Rely X Unicem Clicker, 3M ESPE; MaxCem; KERR, Panavia F 2.0; Kuraray, BisCem; Bisco and Bistite II DC; Tokuyama) was analyzed in a dentin barrier test device using three-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into two compartments by 500 mum dentin disc. The three dimensional cultures placed on a dentin disk held in place by a special biocompatible stainless-steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer's instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with medium (2 ml/h). After an exposure period of 24 h, the cell survival was determined by the MTT assay. Statistical analyses were performed using the Mann-Whitney U-test. In dentin barrier test, cell survival was similar with Maxcem and negative control group (P>.05), and all other tested materials were cytotoxic for the three dimensional cell cultures (P>.05). The significance of composite resin cements is being more important in dentistry. The cytotoxic potencies demonstrated by these materials might be of clinical relevance. Some composite resin cements include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities or directly contact pulp tissue.

Effective control of modified palygorskite to NH4+-N release from sediment.

PubMed

Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

2014-01-01

Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

Facile preparation of nanofiller-paper using mixed office paper without deinking

Treesearch

Qianqian Wang; J.Y. Zhu

2015-01-01

Mixed office paper (MOP) pulp without deinking with an ash content of 18.1 ± 1.5% was used as raw material to produce nanofiller-paper. The MOP pulp with filler was mechanically fibrillated using a laboratory stone grinder. Scanning electron microscope imaging revealed that the ground filler particles were wrapped by cellulose nanofibrils (CNFs), which substantially...

Mill demonstration of TMP production from forest thinnings : pulp quality, refining energy, and handsheet properties

Treesearch

J.Y. Zhu; C. Tim Scott; Roland Gleisner; Doreen Mann; D.P. Dykstra; G. Holton Quinn; Louis L. Edwards

2007-01-01

High-value, large-volume utilization of forest thinning materials from U.S. National Forests is a potentially important contributor to sustainable forest health. This study demonstrated the utilization of wood chips produced from thinnings for the production of thermomechanical pulp (TMP). Both whole-log chips (primarily from small-diameter logs, tops, and reject logs...

Mill demonstration of TMP production from forest thinnings: pulp quality, refining energy, and handsheet properties

Treesearch

J.Y. Zhu; C. Tim Scott; Roland Gleisner; Doreen Mann; D.P. Dykstra; G. Holton Quinn; Louis L. Edwards

2007-01-01

High-value, large-volume utilization of forest thinning materials from U.S. national forests is a potentially important contributor to sustainable forest health. This study demonstrated the utilization of wood chips produced from thinnings for the production of thermomechanical pulp (TMP). Both whole-log chips (primarily from small-diameter logs, tops, and reject logs...

Current Advance and Future Prospects of Tissue Engineering Approach to Dentin/Pulp Regenerative Therapy

PubMed Central

Gong, Ting; Heng, Boon Chin; Lo, Edward Chin Man; Zhang, Chengfei

2016-01-01

Recent advances in biomaterial science and tissue engineering technology have greatly spurred the development of regenerative endodontics. This has led to a paradigm shift in endodontic treatment from simply filling the root canal systems with biologically inert materials to restoring the infected dental pulp with functional replacement tissues. Currently, cell transplantation has gained increasing attention as a scientifically valid method for dentin-pulp complex regeneration. This multidisciplinary approach which involves the interplay of three key elements of tissue engineering—stem cells, scaffolds, and signaling molecules—has produced an impressive number of favorable outcomes in preclinical animal studies. Nevertheless, many practical hurdles need to be overcome prior to its application in clinical settings. Apart from the potential health risks of immunological rejection and pathogenic transmission, the lack of a well-established banking system for the isolation and storage of dental-derived stem cells is the most pressing issue that awaits resolution and the properties of supportive scaffold materials vary across different studies and remain inconsistent. This review critically examines the classic triad of tissue engineering utilized in current regenerative endodontics and summarizes the possible techniques developed for dentin/pulp regeneration. PMID:27069484

Factors affecting the corrosivity of pulping liquors

NASA Astrophysics Data System (ADS)

Hazlewood, Patrick Evan

Increased equipment failures and the resultant increase in unplanned downtime as the result of process optimization programs continue to plague pulp mills. The failures are a result of a lack of understanding of corrosion in the different pulping liquors, specifically the parameters responsible for its adjustment such as the role and identification of inorganic and organic species. The current work investigates the role of inorganic species, namely sodium hydroxide and sodium sulfide, on liquor corrosivity at a range of process conditions beyond those currently experienced in literature. The role of sulfur species, in the activation of corrosion and the ability of hydroxide to passivate carbon steel A516-Gr70, is evaluated with gravimetric and electrochemical methods. The impact of wood chip weathering on process corrosion was also evaluated. Results were used to identify black liquor components, depending on the wood species, which play a significant role in the activation and inhibition of corrosion for carbon steel A516-Gr70 process equipment. Further, the effect of black liquor oxidation on liquor corrosivity was evaluated. Corrosion and stress corrosion cracking performance of selected materials provided information on classes of materials that may be reliably used in aggressive pulping environments.

Polymeric compositions incorporating polyethylene glycol as a phase change material

DOEpatents

Salyer, Ival O.; Griffen, Charles W.

1989-01-01

A polymeric composition comprising a polymeric material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the composition is useful in making molded and/or coated materials such as flooring, tiles, wall panels and the like; paints containing polyethylene glycols or end-capped polyethylene glycols are also disclosed.

Transient aero-thermal mapping of passive Thermal Protection system for nose-cap of Reusable Hypersonic Vehicle

NASA Astrophysics Data System (ADS)

Mahulikar, Shripad P.; Khurana, Shashank; Dungarwal, Ritesh; Shevakari, Sushil G.; Subramanian, Jayakumar; Gujarathi, Amit V.

2008-12-01

The temperature field history of passive Thermal Protection System (TPS) material at the nose-cap (forward stagnation region) of a Reusable Hypersonic Vehicle (RHV) is generated. The 3-D unsteady heat transfer model couples conduction in the solid with external convection and radiation that are modeled as time-varying boundary conditions on the surface. Results are presented for the following two cases: (1) nose-cap comprised of ablative TPS material only (SIRCA/PICA), and (2) nose-cap comprised of a combination of ablative TPS material with moderate thermal conductivity and insulative TPS material. Comparison of the temperature fields of SIRCA and PICA [Case (1)] indicates lowering of the peak stagnation region temperatures for PICA, due to its higher thermal conductivity. Also, the use of PICA and insulative TPS [Case (2)] for the nose-cap has higher potential for weight reduction than the use of ablative TPS alone.

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-04-01

Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

The effect of amphipilic lignin derivatives addition on enzymatic hydrolysis performance of kraft pulp from sorghum bagasse

NASA Astrophysics Data System (ADS)

Fatriasari, Widya; Nugroho Adi, D. T.; Laksana, R. P. B.; Fajriutami, T.; Raniya, R.; Ghozali, M.; Hermiati, E.

2018-03-01

Previously, the chemical characteristics of isolated lignin from Acacia mangium black liquor of kraft pulping was characterized. This lignin was blended with natural rubber latex (NR-L) as adhesive in laminated wood. In addition, lignin has potency for biosurfactant materials by modification of the hydrophobic into hydrophilic properties. Therefore, this study was intended to develop lignin as material for amphipilic lignin derivatives (A-LD) biosurfactant by reacting lignin with epoxilated polyethylene glicol (PEG). A-LD addition in slurries was used to improve the enzymatic hydrolysis (EH) of kraft pulp sweet bagasse sorghum (SSB). The main observation in EH performance was to investigate the effect of lignin isolation method (one and two step) in A-LD and A-LD loading addition on reducing sugar yield (RSY) of SSB kraft pulp. The pulp was hydrolyzed at 50°C and 150 rpm for 72 h with 10 FPU cellulase loading in the shaking incubator. A-LD from one (L1S) and two step (L2S) lignin was added with A-LD loading of 0, 1, 2, 5, and 10% (b/v). The RSY of hydrolyzate has been observed after EH. A-LDs addition in EH of SSB kraft pulp enhanced RSY. L1S worked better in reaction performance with PEDGE compared to L2S and LS. A better performance was showed by PEDGE 500 than that of PEDGE 6000. Generally, the higher A-LDs loading resulted higher RSY. The highest RSY (81.33%) was resulted in addition of 10% A-LD L1S using PEDGE 500. A 5% A-LD loading was more considered to be added in EH because the RSY was comparable with 10% A-LD loading.

An analysis of the timing and materials associated with pulp disease following restorative dental treatment.

PubMed

Yong, J B; Sivarajan, S; Abbott, P V

2018-05-19

To assess whether the timing of pulp disease after tooth restoration was associated with type of restorative dental material used, extent of the restoration, or tooth type. A comprehensive search and analysis of data using the Titanium Oral Health Management software program at The Oral Health Centre of Western Australia was performed to correlate procedural codes for teeth that had restorations placed and subsequently developed pulp disease requiring endodontic treatment or extraction from 1 st January 2009 to 31 st December 2013. Manual analysis of paper and/or electronic patient record cards was also performed. Data collected included restoration type, restored tooth surfaces, tooth type, and the dates of restoration and subsequent endodontic intervention or extraction. Of 330 teeth that met the inclusion criteria, 84 (26%) had composite resin restorations, 80 (24%) had amalgams, 119 (36%) had GICs and 47 (14%) had crowns. The average time between restoration and further intervention was 330 days with a range from 3 days to 1,775 days (approx. 5 years). Teeth restored with crowns or five-surface restorations were significantly more likely to require earlier intervention than other restorations. Premolar and anterior teeth were also more likely to require earlier intervention. Teeth that developed pulp disease requiring further intervention that were restored with crowns and five-surface GIC developed the disease sooner than teeth that were restored with amalgam or composite. In teeth with five surface restorations that developed pulp disease requiring further intervention, premolar and anterior teeth developed the pulp disease sooner than molars. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Calcium Hydroxide-induced Proliferation, Migration, Osteogenic Differentiation, and Mineralization via the Mitogen-activated Protein Kinase Pathway in Human Dental Pulp Stem Cells.

PubMed

Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo

2016-09-01

Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Ozone delignification of pine and eucalyptus kraft pulps. 2: Selectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simoes, R.M.S.; Castro, J.A.A.M.

1999-12-01

The selectivity of ozone in the delignification of unbleached pine and eucalyptus kraft pulps is studied at ultralow consistency in a stirred reactor under closely controlled experimental conditions. The effect of several operating variables is analyzed, but special attention is paid to the depolymerization rate of polysaccharides with the particular goal of evaluating the influence of the lignin contents on its kinetics. By using substantially different ozone concentrations in the pulp suspension and different reaction temperatures, it is possible to show that ozone selectivity can only be slightly improved by manipulating these operating variables. Furthermore, for the same type ofmore » material, it was observed that the initial rate of delignification plays the most important role on selectivity. In fact, for a given pulp, selectivity decreases with a decrease of the initial lignin contents, and such results can be well justified by the corresponding reduction of the initial rates of delignification. To further investigate the effect of lignin on pulp degradation, experiments were carried out at 4 C between ozone and holocellulose, which represent the polysaccharides of the unbleached pulps. The results suggest that molecular ozone can be responsible for an important part of the polysaccharides depolymerization during the delignification process. Moreover, the comparison of the kinetic behavior of holocellulose and of the corresponding unbleached pulp also reveals that the presence of lignin in the pulp enhances both the depolymerization and the degradation rates of polysaccharides.« less

Pulp tissue in sex determination: A fluorescent microscopic study

PubMed Central

Nayar, Amit; Singh, Harkanwal Preet; Leekha, Swati

2014-01-01

Aims: To determine and compare the reliability of pulp tissue in determination of sex and to analyze whether caries have any effect on fluorescent body test. Materials and Methods: This study was carried on 50 maxillary and mandibular teeth (25 male teeth and 25 female teeth), which were indicated for extraction. The teeth are categorized into 5 groups, 10 each (5 from males and 5 from females) on the basis of caries progression. The pulp cells are stained with quinacrine hydrochloride and observed with fluorescent microscope for fluorescent body. Gender is determined by identification of Y chromosome fluorescence in dental pulp. Results: Fluorescent bodies were found to be more in sound teeth in males as the caries increase the mean percentage of fluorescent bodies observed decreases in males. We also observed the fluorescent spots in females, and the value of the spot increases in female as the caries progresses, thereby giving false positive results in females. Conclusion: Sex determination by fluorescent staining of the Y chromosome is a reliable technique in teeth with healthy pulps or caries with enamel or up to half way of dentin. Teeth with caries involving pulp cannot be used for sex determination. PMID:25125912

Electron treatment of wood pulp for the viscose process

NASA Astrophysics Data System (ADS)

Stepanik, T. M.; Ewing, D. E.; Whitehouse, R.

2000-03-01

Electron processing is currently being evaluated by several viscose producers for integration into their process. The viscose industry converts dissolving wood pulp into products such as staple fibre, filament, cord, film, packaging, and non-edible sausage casings. These materials are used in the clothing, drapery, hygiene, automobile, food, and packaging industries. Viscose producers are facing increasingly high production costs and stringent environmental regulations that have forced some plants to close. Electron treatment of wood pulp can significantly reduce the amounts of chemicals used for producing viscose and the production of hazardous pollutants. Acsion Industries has worked with companies worldwide to demonstrate the benefits of using electron treated pulp for producing viscose (rayon). This paper describes the viscose process, the benefits of using electron treatment in the viscose process, and Acsion's efforts in developing this technology.

Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

DOEpatents

Salyer, Ival O.; Griffen, Charles W.

1986-01-01

A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

Analysis of radiopacity, pH and cytotoxicity of a new bioceramic material.

PubMed

Souza, Letícia Chaves de; Yadlapati, Mamatha; Dorn, Samuel O; Silva, Renato; Letra, Ariadne

2015-01-01

RetroMTA® is a new hydraulic bioceramic indicated for pulp capping, perforations or root resorption repair, apexification and apical surgery. The aim of this study was to compare the radiopacity, pH variation and cytotoxicity of this material to ProRoot® MTA. Mixed cements were exposed to a digital x-ray along with an aluminum stepwedge for the radiopacity assay. pH values were verified after incubation period of 3, 24, 48, 72 and 168 hours. The cytotoxicity of each cement was tested on human periodontal ligament fibroblasts using a multiparametric assay. Data analysis was performed using ANOVA and Tukey'spost hoc in GraphPad Prism. ProRoot® MTA had higher radiopacity than RetroMTA®(p<0.001). No significant differences were observed for the pH of the materials throughout experimental periods (p>0.05) although pH levels of both materials reduced over time. Both ProRoot® MTA and RetroMTA® allowed for significantly higher cell viability when compared with the positive control (p<0.001). No statistical difference was observed between ProRoot® MTA and RetroMTA® cytotoxicity level in all test parameters, except for the ProRoot® MTA 48-hour extract media in the NR assay (p<0.05). The current study provides new data about the physicochemical and biological properties of Retro® MTA concerning radiopacity, pH and cytotoxic effects on human periodontal ligaments cells. Based on our findings, RetroMTA® meets the radiopacity requirements standardized by ANSI/ADA number 572, and similar pH values and biocompatibility to ProRoot® MTA. Further studies should be performed to evaluate additional properties of this new material.

Interferon-gamma improves impaired dentinogenic and immunosuppressive functions of irreversible pulpitis-derived human dental pulp stem cells

PubMed Central

Sonoda, Soichiro; Yamaza, Haruyoshi; Ma, Lan; Tanaka, Yosuke; Tomoda, Erika; Aijima, Reona; Nonaka, Kazuaki; Kukita, Toshio; Shi, Songtao; Nishimura, Fusanori; Yamaza, Takayoshi

2016-01-01

Clinically, irreversible pulpitis is treated by the complete removal of pulp tissue followed by replacement with artificial materials. There is considered to be a high potential for autologous transplantation of human dental pulp stem cells (DPSCs) in endodontic treatment. The usefulness of DPSCs isolated from healthy teeth is limited. However, DPSCs isolated from diseased teeth with irreversible pulpitis (IP-DPSCs) are considered to be suitable for dentin/pulp regeneration. In this study, we examined the stem cell potency of IP-DPSCs. In comparison with healthy DPSCs, IP-DPSCs expressed lower colony-forming capacity, population-doubling rate, cell proliferation, multipotency, in vivo dentin regeneration, and immunosuppressive activity, suggesting that intact IP-DPSCs may be inadequate for dentin/pulp regeneration. Therefore, we attempted to improve the impaired in vivo dentin regeneration and in vitro immunosuppressive functions of IP-DPSCs to enable dentin/pulp regeneration. Interferon gamma (IFN-γ) treatment enhanced in vivo dentin regeneration and in vitro T cell suppression of IP-DPSCs, whereas treatment with tumor necrosis factor alpha did not. Therefore, these findings suggest that IFN-γ may be a feasible modulator to improve the functions of impaired IP-DPSCs, suggesting that autologous transplantation of IFN-γ-accelerated IP-DPSCs might be a promising new therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment. PMID:26775677

Effectiveness and biological compatibility of different generations of dentin adhesives.

PubMed

da Silva, João M F; Rodrigues, José R; Camargo, Carlos H R; Fernandes, Virgilio Vilas Boas; Hiller, Karl-Anton; Schweikl, Helmut; Schmalz, Gottfried

2014-01-01

Besides possessing good mechanical properties, dental materials should present a good biological behavior and should not injure the involved tissues. Bond strength and biocompatibility are both highly significant properties of dentin adhesives. For that matter, these properties of four generations of adhesive systems (Multi-Purpose/Single Bond/SE Plus/Easy Bond) were evaluated. Eighty bovine teeth had their dentin exposed (500- and 200-μm thickness). Adhesive was applied on the dentin layer of each specimen. Following that, the microshearing test was performed for all samples. A dentin barrier test was used for the cytotoxicity evaluation. Cell cultures (SV3NeoB) were collected from testing materials by means of 200- or 500-μm-thick dentin slices and placed in a cell culture perfusion chamber. Cell viability was measured 24 h post-exposition by means of a photometrical test (MTT test). The best bonding performance was shown by the single-step adhesive Easy Bond (21 MPa, 200 μm; 27 MPa, 500 μm) followed by Single Bond (15.6 MPa, 200 μm; 23.4 MPa, 500 μm), SE Plus (18.2 MPa, 200 μm; 20 MPa, 500 μm), and Multi-Purpose (15.2 MPa, 200 μm; 17.9 MPa, 500 μm). Regarding the cytotoxicity, Multi-Purpose slightly reduced the cell viability to 92% (200 μm)/93% (500 μm). Single Bond was reasonably cytotoxic, reducing cell viability to 71% (200 μm)/64% (500 μm). The self-etching adhesive Scotchbond SE decreased cell viability to 85% (200 μm)/71% (500 μm). Conversely, Easy Bond did not reduce cell viability in this test, regardless of the dentin thickness. Results showed that the one-step system had the best bond strength performance and was the least toxic to pulp cells. In multiple-step systems, a correct bonding technique must be done, and a pulp capping strategy is necessary for achieving good performance in both properties. The study showed a promising system (one-step self-etching), referring to it as a good alternative for specific cases, mainly due to its technical simplicity and good biological responses.

Morphological and functional changes in RAW264 macrophage-like cells in response to a hydrated layer of carbonate-substituted hydroxyapatite.

PubMed

Igeta, Kazuki; Kuwamura, Yuta; Horiuchi, Naohiro; Nozaki, Kosuke; Shiraishi, Daichi; Aizawa, Mamoru; Hashimoto, Kazuaki; Yamashita, Kimihiro; Nagai, Akiko

2017-04-01

Synthetic hydroxyapatite (HAp) is used clinically as a material for bone prostheses owing to its good bone-bonding ability; however, it does not contribute to bone remodeling. Carbonate-substituted hydroxyapatite (CAp) has greater bioresorption capacity than HAp while having similar bone-bonding potential, and is therefore considered as a next promising material for bone prostheses. However, the effects of the CAp instability on inflammatory and immune responses are unknown in detail. Here, we show that the surface layer of CAp is more hydrated than that of HAp and induces changes in the shape and function of macrophage-like cells. HAp and CAp were synthesized by wet method and molded into disks. The carbonate content of CAp disks was 6.2% as determined by Fourier transform (FT) infrared spectral analysis. Diffuse reflectance infrared FT analysis confirmed that physisorbed water and surface hydroxyl groups (OH - ) were increased whereas structural OH - was decreased on the CAp as compared to the HAp surface. The degree of hydroxylation in CAp was comparable to that in bone-apatite structures, and the CAp surface exhibited greater hydrophilicity and solubility than HAp. We investigated immune responses to these materials by culturing RAW264 cells (macrophage precursors) on their surfaces. Cell spreading on the CAp disk was suppressed and the secretion level of inflammatory cytokines was reduced as compared to cells grown on HAp. These results indicate that the greater surface hydration of CAp surface can attenuate adverse inflammatory responses to implanted bone prostheses composed of this material. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1063-1070, 2017. © 2017 Wiley Periodicals, Inc.

Inverted channel deposits on the floor of Miyamoto crater, Mars

USGS Publications Warehouse

Newsom, Horton E.; Lanza, N.L.; Ollila, A.M.; Wiseman, S.M.; Roush, T.L.; Marzo, G.A.; Tornabene, L.L.; Okubo, C.H.; Osterloo, M.M.; Hamilton, V.E.; Crumpler, L.S.

2010-01-01

Morphological features on the western floor of Miyamoto crater in southwestern Meridiani Planum, Mars, are suggestive of past fluvial activity. Imagery from the High Resolution Imaging Science Experiment (HiRISE) gives a detailed view of raised curvilinear features that appear to represent inverted paleochannel deposits. The inverted terrain appears to be capped with a resistant, dark-toned deposit that is partially covered by unconsolidated surficial materials. Subsequent to deposition of the capping layer, erosion of the surrounding material has left the capping materials perched on pedestals of uneroded basal unit material. Neither the capping material nor the surrounding terrains show any unambiguous morphological evidence of volcanism or glaciation. The capping deposit may include unconsolidated or cemented stream deposits analogous to terrestrial inverted channels in the Cedar Mountain Formation near Green River, Utah. In addition to this morphological evidence for fluvial activity, phyllosilicates have been identified in the basal material on the floor of Miyamoto crater by orbital spectroscopy, providing mineralogical evidence of past aqueous activity. Based on both the morphological and mineralogical evidence, Miyamoto crater represents an excellent site for in situ examination and sampling of a potentially habitable environment. ?? 2009 Elsevier Inc.

Adult stem cell-based apexogenesis

PubMed Central

Li, Yao; Shu, Li-Hong; Yan, Ming; Dai, Wen-Yong; Li, Jun-Jun; Zhang, Guang-Dong; Yu, Jin-Hua

2014-01-01

Generally, the dental pulp needs to be removed when it is infected, and root canal therapy (RCT) is usually required in which infected dental pulp is replaced with inorganic materials (paste and gutta percha). This treatment approach ultimately brings about a dead tooth. However, pulp vitality is extremely important to the tooth itself, since it provides nutrition and acts as a biosensor to detect the potential pathogenic stimuli. Despite the reported clinical success rate, RCT-treated teeth are destined to be devitalized, brittle and susceptible to postoperative fracture. Recently, the advances and achievements in the field of stem cell biology and regenerative medicine have inspired novel biological approaches to apexogenesis in young patients suffering from pulpitis or periapical periodontitis. This review mainly focuses on the benchtop and clinical regeneration of root apex mediated by adult stem cells. Moreover, current strategies for infected pulp therapy are also discussed here. PMID:25332909

Inflammatory response of human dental pulp to at-home and in-office tooth bleaching

PubMed Central

Vaz, Maysa Magalhães; Lopes, Lawrence Gonzaga; Cardoso, Paula Carvalho; de Souza, João Batista; Batista, Aline Carvalho; Costa, Nádia Lago; Torres, Érica Miranda; Estrela, Carlos

2016-01-01

ABSTRACT Tooth bleaching is a technique of choice to obtain a harmonious smile, but bleaching agents may damage the dental pulp. Objective: This study evaluated the inflammatory responses of human dental pulp after the use of two bleaching techniques. Material and Methods: Pulp samples were collected from human third molars extracted for orthodontic reasons and divided into three groups: control - no tooth bleaching (CG) (n=7); at-home bleaching with 15% carbamide peroxide (AH) (n = 10), and in-office bleaching with 38% hydrogen peroxide (IO) (n=12). Pulps were removed and stained with hematoxylin-eosin for microscopic analysis of inflammation intensity, collagen degradation, and pulp tissue organization. Immunohistochemistry was used to detect mast cells (tryptase+), blood vessels (CD31+), and macrophages (CD68+). Chi-square, Kruskal-Wallis, and Mann Whitney tests were used for statistical analysis. The level of significance was set at p<.05. Results: The inflammation intensity and the number of macrophages were significantly greater in IO than in AH and CG (p<0.05). The results of CD31+ (blood vessels per mm2) were similar in CG (61.39±20.03), AH (52.29±27.62), and IO (57.43±8.69) groups (p>0.05). No mast cells were found in the pulp samples analyzed. Conclusion: In-office bleaching with 38% hydrogen peroxide resulted in more intense inflammation, higher macrophages migration, and greater pulp damage then at-home bleaching with 15% carbamide peroxide, however, these bleaching techniques did not induce migration of mast cells and increased the number of blood vessels. PMID:27812622

Efficient exfoliation of layered materials by waste liquor

NASA Astrophysics Data System (ADS)

Ding, Jiheng; Zhao, Hongran; Zheng, Yan; Wang, Qiaolei; Chen, Hao; Dou, Huimin; Yu, Haibin

2018-03-01

Based on their unique material properties, two-dimensional (2D) nanomaterials such as graphene, molybdenum disulfide (MoS2), and boron nitride (BN) have been attracting increased research interest. The potential of 2D materials, in the form of nanoplatelets that are used as new materials, will be important to both nanomaterials and advanced materials. Water is usually considered to be the ideal dispersed medium, and the essential hydrophobicity and limitations to mass production of 2D nanoplatelets have become quite serious obstacles to their usage in various fields. In this paper, pulping black liquor was used as dispersant, with high concentration of lignin to get single- and few-layered nanoplatelets. The whole process required only the high-shear mixing of 2D layered materials and pulping waste liquor. This method was not only simple and efficient but also environmentally friendly and resource-recycling. Moreover, the fabricated single- or few-layered nanoplatelets possessed good solubility in aqueous solution due to their edge functionalization, and could be well dispersed in water at concentrations (10 mg ml-1 for graphene, 6.3 mg ml-1 for MoS2, and 6.0 mg ml-1 for BN) which were much higher than that of other methods. The dispersions of graphene, MoS2, and BN nanosheets were highly stable over several months, which allowed us to easily prepare graphene, MoS2, and BN films through simple vacuum filtration or spraying. These results indicated that pulping black liquor can be used as a material or reagent, and the mass production of 2D material is possible in a simple and fast method.

The Potential in Bioethanol Production From Waste Fiber Sludges in Pulp Mill-Based Biorefineries

NASA Astrophysics Data System (ADS)

Sjöde, Anders; Alriksson, Björn; Jönsson, Leif J.; Nilvebrant, Nils-Olof

Industrial production of bioethanol from fibers that are unusable for pulp production in pulp mills offers an approach to product diversification and more efficient exploitation of the raw material. In an attempt to utilize fibers flowing to the biological waste treatment, selected fiber sludges from three different pulp mills were collected, chemically analyzed, enzymatically hydrolyzed, and fermented for bioethanol production. Another aim was to produce solid residues with higher heat values than those of the original fiber sludges to gain a better fuel for combustion. The glucan content ranged between 32 and 66% of the dry matter. The lignin content varied considerably (1-25%), as did the content of wood extractives (0.2-5.8%). Hydrolysates obtained using enzymatic hydrolysis were found to be readily fermentable using Saccharomyces cerevisiae. Hydrolysis resulted in improved heat values compared with corresponding untreated fiber sludges. Oligomeric xylan fragments in the solid residue obtained after enzymatic hydrolysis were identified using matrix-assisted laser desorption ionization-time of flight and their potential as a new product of a pulp mill-based biorefinery is discussed.

Manufacture of dissolving pulps from cornstalk by novel method coupling steam explosion and mechanical carding fractionation.

PubMed

Wang, Ning; Chen, Hong-Zhang

2013-07-01

In order to solve the inhomogeneity of cornstalk as fiber material to manufacture dissolving pulp, a novel method of steam explosion coupling mechanical carding was put forward to fractionate cornstalk long fiber for the production of cornstalk dissolving pulp. The fractionated long fiber had homogeneous structure and low hemicellulose and ash content. The fiber cell content was up to 85% in area, and the hemicellulose and ash content was 8.34% and 1.10% respectively. The α-cellulose content of cornstalk dissolving pulps was up to 93.10-97.10%, the viscosity was 14.37-23.96 mPas, and the yields of cornstalk dissolving pulps were from 10.11% to 12.44%. In addition, the fractionated short fiber was to be hydrolyzed by enzyme to build sugar platform. The constructed method of steam explosion coupling mechanical carding achieved the fractionation of cornstalk into long fiber and short fiber cleanly and effectively, and provided a new way for cornstalk integrated refinery. Copyright © 2013 Elsevier Ltd. All rights reserved.

The potential in bioethanol production from waste fiber sludges in pulp mill-based biorefineries.

PubMed

Sjöde, Anders; Alriksson, Björn; Jönsson, Leif J; Nilvebrant, Nils-Olof

2007-04-01

Industrial production of bioethanol from fibers that are unusable for pulp production in pulp mills offers an approach to product diversification and more efficient exploitation of the raw material. In an attempt to utilize fibers flowing to the biological waste treatment, selected fiber sludges from three different pulp mills were collected, chemically analyzed, enzymatically hydrolyzed, and fermented for bioethanol production. Another aim was to produce solid residues with higher heat values than those of the original fiber sludges to gain a better fuel for combustion. The glucan content ranged between 32 and 66% of the dry matter. The lignin content varied considerably (1-25%), as did the content of wood extractives (0.2-5.8%). Hydrolysates obtained using enzymatic hydrolysis were found to be readily fermentable using Saccharomyces cerevisiae. Hydrolysis resulted in improved heat values compared with corresponding untreated fiber sludges. Oligomeric xylan fragments in the solid residue obtained after enzymatic hydrolysis were identified using matrix-assisted laser desorption ionization-time of flight and their potential as a new product of a pulp mill-based biorefinery is discussed.

Review on recent developments on pulp and paper mill wastewater treatment.

PubMed

Kamali, Mohammadreza; Khodaparast, Zahra

2015-04-01

Economic benefits of the pulp and paper industry have led it to be one of the most important industrial sections in the world. Nevertheless, in recent years, pulp and paper mills are facing challenges with the energy efficiency mechanisms and management of the resulting pollutants, considering the environmental feedbacks and ongoing legal requirements. This study reviews and discusses the recent developments of affordable methods dealing with pulp and paper mill wastewaters. To this end, the current state of the various processes used for pulp and paper production from virgin or recovered fibers has been briefly reviewed. Also, the relevant contaminants have been investigated, considering the used raw materials and applied techniques as the subject for further discussion about the relevant suitable wastewater treatment methods. The results of the present study indicated that adopting the integrated methods, alongside a combination of biological (e.g., anaerobic digestion) and physicochemical (e.g., novel Fenton reactions) treatment methods, can be environmentally and economically preferable to minimize environmental contaminants and energy recycling. Copyright © 2014 Elsevier Inc. All rights reserved.

Activated carbon prepared from coffee pulp: potential adsorbent of organic contaminants in aqueous solution.

PubMed

Gonçalves, Maraisa; Guerreiro, Mário César; Ramos, Paulize Honorato; de Oliveira, Luiz Carlos Alves; Sapag, Karim

2013-01-01

The processing of coffee beans generates large amounts of solid and liquid residues. The solid residues (pulp, husk and parchment) represent a serious environmental problem and do not have an adequate disposal mechanism. In this work, activated carbons (ACs) for adsorption of organic compounds were prepared from coffee pulp by controlled temperature at different pulp/Na2HPO4 ratios (4:1, 2:1, 5:4 and 1:1). The N2 adsorption/desorption isotherms showed ACs with high quantities of mesopores and micropores and specific surface areas of 140, 150, 450 and 440 m(2)g(-1) for AC 4:1, AC 2:1, AC 5:4 and AC 1:1, respectively. The prepared material AC 5:4 showed a higher removal capacity of the organic contaminants methylene blue (MB), direct red (DR) and phenol than did a Merck AC. The maximum capacities for this AC are approximately 150, 120 and 120 mg g(-1) for MB, DR and phenol, respectively. Thus, a good adsorbent was obtained from coffee pulp, an abundant Brazilian residue.

Evaluating chemical-, mechanical-, and bio-pulping processes and their sustainability characterization using life cycle assessment

Treesearch

Tapas K. Das; Carl Houtman

2004-01-01

Pulp and paper manufacturing constitutes one of the largest industry segments in the United States in term of water and energy usage and total discharges to the environment. More than many other industries, however, this industry plays an important role in sustainable development because its chief raw material— wood fiber—is renewable. This industry provides an example...

Thermal Scanning of Dental Pulp Chamber by Thermocouple System and Infrared Camera during Photo Curing of Resin Composites.

PubMed

Hamze, Faeze; Ganjalikhan Nasab, Seyed Abdolreza; Eskandarizadeh, Ali; Shahravan, Arash; Akhavan Fard, Fatemeh; Sinaee, Neda

2018-01-01

Due to thermal hazard during composite restorations, this study was designed to scan the pulp temperature by thermocouple and infrared camera during photo polymerizing different composites. A mesio-occlso-distal (MOD) cavity was prepared in an extracted tooth and the K-type thermocouple was fixed in its pulp chamber. Subsequently, 1 mm increment of each composites were inserted (four composite types were incorporated) and photo polymerized employing either LED or QTH systems for 60 sec while the temperature was recorded with 10 sec intervals. Ultimately, the same tooth was hemisected bucco-lingually and the amalgam was removed. The same composite curing procedure was repeated while the thermogram was recorded using an infrared camera. Thereafter, the data was analyzed by repeated measured ANOVA followed by Tukey's HSD Post Hoc test for multiple comparisons ( α =0.05). The pulp temperature was significantly increased (repeated measures) during photo polymerization ( P =0.000) while there was no significant difference among the results recorded by thermocouple comparing to infrared camera ( P >0.05). Moreover, different composite materials and LCUs lead to similar outcomes ( P >0.05). Although various composites have significant different chemical compositions, they lead to similar pulp thermal changes. Moreover, both the infrared camera and the thermocouple would record parallel results of dental pulp temperature.

Effect of novel chitosan-fluoroaluminosilicate resin modified glass ionomer cement supplemented with translationally controlled tumor protein on pulp cells.

PubMed

Wanachottrakul, Nattaporn; Chotigeat, Wilaiwan; Kedjarune-Leggat, Ureporn

2014-04-01

Dental materials that can promote cell proliferation and function is required for regenerative pulp therapy. Resin modified glass ionomer cement (RMGIC), a broadly used liner or restorative material, can cause apoptosis to pulp cells mainly due to HEMA (2-hydroxyethyl methacrylate), the released residual monomer. Recent studies found that chitosan and albumin could promote release of protein in GIC while translationally controlled tumor protein (TCTP) has an anti-apoptotic activity against HEMA. The aim of this study was to examine the effect of chitosan and albumin modified RMGIC (Exp-RMGIC) supplemented with TCTP on pulp cell viability and mineralization. Exp-RMGIC+TCTP was composed of RMGIC powder incorporated with 15 % of chitosan, 5 % albumin and supplemented with TCTP mixed with the same liquid components of RMGIC. The effect of each specimen on pulp cells was examined using the Transwell plate. From the MTT assay, Exp-RMGIC+TCTP had the highest percentages of viable cells (P < 0.05) at both 24 and 74 h. Flow cytometry revealed that, after 24 h, Exp-RMGIC+TCTP gave the lowest percentages of apoptotic cells compared to other groups. There was no difference in alkaline phosphatase (ALP) activity among different formula of the specimens, while cells cultured in media with TCTP had higher ALP activity. Von Kossa staining revealed that RMGIC+TCTP, and Exp-RMGIC+TCTP had higher percentages of calcium deposit area compared to those without TCTP. It was concluded that Exp-RMGIC supplemented with TCTP had less cytotoxicity than RMGIC and can protect cells from apoptosis better than RMGIC supplemented with TCTP.

Investigation of salt distribution in porous stone material using paper pulp poultices under laboratory condititions and on site

NASA Astrophysics Data System (ADS)

Egartner, Isabel; Sass, Oliver

2016-04-01

The presented investigation is part of a longer-term project which deals with the influence of salt and moisture on weathering of historic stonework. The main investigation object in the field is a part of the 300 hundred year old boundary wall of the Worchester College in Oxford, UK. A range of non-destructive techniques were applied in course of field campaigns, e.g. mapping of weathering phenomena; handheld moisture sensors; and salt sampling by paper pulp poultices. In a second step we investigated the behaviour and distribution of water and salt solution in a porous material, similar to the limestone of the College wall, under laboratory condititions. Limestone cube samples (5x5x5 cm) were soaked first with ultrapure H2O and second with different concentration of saline solutions of NaCl and Na2SO4. During the dehydration process of the stone cubes a multi-method approach including sampling by drilling, paper pulp poultices, handheld moisture sensor, conductivity sensor and Ion Chromatography (IC) were applied to investigate the moisture and salt content and distribution within the samples. The laboratory analyses were carried out at the department of applied geoscience of the Technical University of Graz, Austria. The main aim was to investigate the effectivity of the paper pulp poultices in soaking up salts from the stone samples and to use the results of the laboratory analysis to interpret and calibrate the field work results from the College wall in Oxford. Keywords: Salt weathering, paper pulp poultices, cultural heritage, field work and laboratory investigation

EPA'S FIELD DEMONSTRATION OF INNOVATIVE CAPPING TECHNOLOGIES FOR THE RISK MANAGEMENT OF CONTAMINATED SEDIMENTS

EPA Science Inventory

Research on capping technologies is directed at assessing the effectiveness of innovative capping materials, factors that control contaminant release at the sediment-water interface, installation of cap, resuspension mechanism, and gas ebullition. U.S. EPA's Land Remediation and ...

Three-dimensional culture of dental pulp stem cells in direct contact to tricalcium silicate cements.

PubMed

Widbiller, M; Lindner, S R; Buchalla, W; Eidt, A; Hiller, K-A; Schmalz, G; Galler, K M

2016-03-01

Calcium silicate cements are biocompatible dental materials applicable in contact with vital tissue. The novel tricalcium silicate cement Biodentine™ offers properties superior to commonly used mineral trioxide aggregate (MTA). Objective of this study was to evaluate its cytocompatibility and ability to induce differentiation and mineralization in three-dimensional cultures of dental pulp stem cells after direct contact with the material. Test materials included a new tricalcium silicate (Biodentine™, Septodont, Saint-Maur-des-Fossés, France), MTA (ProRoot® MTA, DENSPLY Tulsa Dental Specialities, Johnson City, TN, USA), glass ionomer (Ketac™ Molar Aplicap™, 3M ESPE, Seefeld, Germany), human dentin disks and polystyrene. Magnetic activated cell sorting for to the surface antigen STRO-1 was performed to gain a fraction enriched with mesenchymal stem cells. Samples were allowed to set and dental pulp stem cells in collagen carriers were placed on top. Scanning electron microscopy of tricalcium silicate cement surfaces with and without cells was conducted. Cell viability was measured for 14 days by MTT assay. Alkaline phosphatase activity was evaluated (days 3, 7, and 14) and expression of mineralization-associated genes (COL1A1, ALP, DSPP, and RUNX2) was quantified by real-time quantitative PCR. Nonparametric statistical analysis for cell viability and alkaline phosphatase data was performed to compare different materials as well as time points (Mann-Whitney U test, α = 0.05). Cell viability was highest on tricalcium silicate cement, followed by MTA. Viability on glass ionomer cement and dentin disks was significantly lower. Alkaline phosphatase activity was lower in cells on new tricalcium silicate cement compared to MTA, whereas expression patterns of marker genes were alike. Increased cell viability and similar levels of mineralization-associated gene expression in three-dimensional cell cultures on the novel tricalcium silicate cement and mineral trioxide aggregate indicate that the material is cytocompatible and bioactive. The tested new tricalcium silicate cement confirms its suitability as an alternative to MTA in vital pulp therapy.

Characteristics of dental pulp in human upper first premolar teeth based on immunohistochemical and morphometric examinations.

PubMed

Tomaszewska, Joanna Maria; Miskowiak, Bogdan; Matthews-Brzozowska, Teresa; Wierzbicki, Piotr

2013-01-01

Teeth extracted for orthodontic reasons are commonly considered as healthy. Therefore, it is possible to examine structure of the dental pulp can be fully recognized and how it is affected by malocclusion. The aim of the study was to evaluate by immunohistochemistry (IHC) and morphometry dental pulp in human upper first premolar teeth extracted for orthodontic reasons. The material comprised 36 teeth of 20 patients in the age range 16-26 years. By the use of IHC markers the presence of immunocompetent cells (CD20, CD45RO, and CD68), blood vessels (CD31) and nerves (PGP9.5) were examined in the pulp. Inflammatory infiltrates and tissue atrophy were observed in 24 and 10 teeth, respectively. Strong positive correlation between the width of the odontoblastic layer, the number of rows of odontoblast nuclei and the increase of MVA (microvessel area) in the pulp of atrophic teeth was found. The cellular infiltrations found in H&E-stained sections were identified by IHC as memory T cells (CD45RO+) and B lymphocytes (CD20+) with macrophages (CD68+) present at the periphery. The CD20 antigen was intensively expressed in 13 teeth, CD45RO in 33 teeth, and CD68 in 20 teeth. Thus, despite the lack of any clinical signs of pulp disease many teeth extracted for orthodontic reasons show focal pulp inflammation and atrophy which probably results from the malocclusion stress accompanying teeth crowding.

IGF-1 and TGF-β stimulate cystine/glutamate exchange activity in dental pulp cells

PubMed Central

Pauly, Katherine; Fritz, Kimberly; Furey, Alyssa; Lobner, Doug

2011-01-01

Introduction The growth factors IGF-1 and TGF-β are protective to dental pulp cells in culture against the toxicity of the composite materials Durafill VS and Flow Line. Since the toxicity of these materials is mediated by oxidative stress, it seemed possible that the protective effects of IGF-1 and TGF-β were through enhancement of an endogenous antioxidant mechanism. Methods We used cultured dental pulp cells to determine the mechanism of the protective effects of IGF-1 and TGF-β, focusing on the glutathione system and the role of cystine/glutamate exchange (system xc-). Results We found that the toxicity of Durafill VS and Flow Line was attenuated by addition of glutathione monoethylester, suggesting a specific role for the cellular antioxidant glutathione. Supporting this hypothesis we found that IGF-1 and TGF-β were protective against the toxicity of the glutathione synthesis inhibitor buthionine sulfoximine. Since levels of cellular cystine are the limiting factor in the production of glutathione we tested the effects of IGF-1 and TGF-β on cystine uptake. Both growth factors stimulated system xc- mediated cystine uptake. Furthermore, they attenuated the glutathione depletion induced by Durafill VS and Flow Line. Conclusions The results suggest that IGF-1 and TGF-β are protective through the stimulation of system xc- mediated cystine uptake leading to maintenance of cellular glutathione. This novel action of growth factors on dental pulp cells has implications not only for preventing toxicity of dental materials but also for the general function of these cells. PMID:21689549

Economic potential of short-rotation woody crops on agricultural land for pulp fiber production in the United States.

Treesearch

Ralph J. Alig; Darius M. Adams; Bruce A. McCarl; Peter J. Ince

2000-01-01

A model of the U.S. forestry and agricultural sectors is used to simulate the consequences of growing short-rotation woody crops on agricultural lands as a fiber source for pulp and paper production. Hybrid poplar, a short-rotation woody crop, annually produces 4 to 7 dry tons per acre of hardwood pulpwood over a 6- to 10-year rotation. When harvested, the material...

Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

PubMed

Méndez, A; Barriga, S; Fidalgo, J M; Gascó, G

2009-06-15

This paper deals with the removal of Cu(2+) from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (V(mic)/V(T)=0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (V(mic)/V(T)=0.39 and 0.41). Adsorbent materials were then used for Cu(2+) removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO(3) content. In general, highest Cu(2+) removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO(3) amount and high Ca and Mg exchange content.

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes, João Eduardo; Briso, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents. PMID:27008262

Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover.

PubMed

Kadam, Kiran L; Chin, Chim Y; Brown, Lawrence W

2008-05-01

A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are juxtaposed with market penetration and saturation.

Pulp tissue dissolution capacity of QMix 2in1 irrigation solution

PubMed Central

Arslan, Dilara; Guneser, Mehmet Burak; Kustarci, Alper; Er, Kursat; Siso, Seyda Herguner

2015-01-01

Objective: The aim of this study was to evaluate the tissue dissolution efficacy of four root canal irrigation solutions (sodium hypochlorite [NaOCl], chlorhexidine gluconate [CHX], Octenidine [OCT], and QMix 2in1) on bovine pulp tissue. Materials and Methods: Fifty bovine pulp tissue samples, each weighing 6.55 mg, were prepared and randomly divided into four experimental groups and one control group (n = 10) according to the dissolution irrigants used: (1) 5.25% NaOCl group; (2) 2% CHX group; (3) OCT group; (4) QMix 2in1 group; and (5) control group (saline solution). These samples were then placed into special bovine dentin reservoir models and immersed for 1 h with each test solution (0.1 mL of each) at room temperature. The pulp samples were then blotted dry and weighed again. The percentage of weight loss was calculated. Statistically analyzed with one-way analysis of variance and post-hoc Tukey tests (P = 0.05). Results: Saline solution did not dissolve the bovine pulp tissue. All groups, except OCT, dissolved pulp samples more effectively than the control group (P < 0.05). The highest tissue dissolution was observed in 5.25% NaOCl group (P < 0.05). No statistically significant difference was found between the tissue-dissolving effect between QMix 2in1 and those of 2% CHX. Conclusions: Within the limitations of this in vitro study, NaOCl exhibited the best tissue-dissolving effect out of all solutions tested. CHX and QMix 2in1 were able to dissolve pulp tissue but less than NaOCl. OCT and saline solutions could not exhibit significantly tissue-dissolving effectiveness. This study shown that QMix 2in1 has little capacity to dissolve pulp tissue therefore used alone is not sufficient for this purpose. PMID:26430374

PILOT IN SITU CAPPING PROJECT FOR PALOS VERDES SHELF CONTAMINATED SEDIMENTS

EPA Science Inventory

The Palos Verdes Shelf Pilot Capping Project will evaluate the short-term results of capping the DDT- and PCB-contaminated sediment with clean sediment. It will also determine how these results are affected by variables such as cap material, placement method and water depth. The ...

Oil goldenberry (Physalis peruviana L.).

PubMed

Ramadan, Mohamed F; Mörsel, Jörg-T

2003-02-12

Whole berries, seeds, and pulp/peel of goldenberry (Physalis peruviana L.) were compared in terms of fatty acids, lipid classes, triacylglyerols, phytosterols, fat-soluble vitamins, and beta-carotene. The total lipid contents in the whole berries, seeds, and seedless parts were 2.0, 1.8, and 0.2% (on a fresh weight basis), respectively. Linoleic acid was the dominating fatty acid followed by oleic acid as the second major fatty acid. Palmitic and stearic acids were the major saturates. In pulp/peel oil, the fatty acid profile was characterized by higher amounts of saturates, monoenes, and trienes than in whole berry and seed oils. Neutral lipids comprised >95% of total lipids in whole berry oil and seed oil, while neutral lipids separated in lower level in pulp/peel oil. Triacylglycerols were the predominant neutral lipid subclass and constituted ca. 81.6, 86.6, and 65.1% of total neutral lipids in whole berry, seed, and pulp/peel oils, respectively. Nine triacylglycerol molecular species were detected, wherein three species, C54:3, C52:2, and C54:6, were presented to the extent of approximately 91% or above. The highest level of phytosterols was estimated in pulp/peel oil that contained the highest level of unsaponifiables. In both whole berry and seed oils, campesterol and beta-sitosterol were the sterol markers, whereas Delta5-avenasterol and campesterol were the main 4-desmethylsterols in pulp/peel oil. The tocopherols level was much higher in pulp/peel oil than in whole berry and seed oils. beta- and gamma-tocopherols were the major components in whole berry and seed oils, whereas gamma- and alpha-tocopherols were the main constituents in pulp/peel oil. beta-Carotene and vitamin K(1) were also measured in markedly high levels in pulp/peel oil followed by whole berry oil and seed oil, respectively. Information provided by the present work is of importance for further chemical investigation of goldenberry oil and industrial utilization of the berries as a raw material of oils and functional foods.

A Customized Self-Assembling Peptide Hydrogel for Dental Pulp Tissue Engineering

PubMed Central

Hartgerink, Jeffrey D.; Cavender, Adriana C.; Schmalz, Gottfried

2012-01-01

Root canal therapy is common practice in dentistry. During this procedure, the inflamed or necrotic dental pulp is removed and replaced with a synthetic material. However, recent research provides evidence that engineering of dental pulp and dentin is possible by using biologically driven approaches. As tissue engineering strategies hold the promise to soon supersede conventional root canal treatment, there is a need for customized scaffolds for stem cell delivery or recruitment. We hypothesize that the incorporation of dental pulp-derived stem cells with bioactive factors into such a scaffold can promote cell proliferation, differentiation, and angiogenesis. In this study, we used a cell adhesive, enzyme-cleavable hydrogel made from self-assembling peptide nanofibers to encapsulate dental pulp stem cells. The growth factors (GFs) fibroblast growth factor basic, transforming growth factor β1, and vascular endothelial growth factor were incorporated into the hydrogel via heparin binding. Release profiles were established, and the influence of GFs on cell morphology and proliferation was assessed to confirm their bioactivity after binding and subsequent release. Cell morphology and spreading in three-dimensional cultures were visualized by using cell tracker and histologic stains. Subcutaneous transplantation of the hydrogel within dentin cylinders into immunocompromised mice led to the formation of a vascularized soft connective tissue similar to dental pulp. These data support the use of this novel biomaterial as a highly promising candidate for future treatment concepts in regenerative endodontics. PMID:21827280

Continuous bio-catalytic conversion of sugar mixture to acetone-butanol-ethanol by immobilized Clostridium acetobutylicum DSM 792.

PubMed

Survase, Shrikant A; van Heiningen, Adriaan; Granström, Tom

2012-03-01

Continuous production of acetone, n-butanol, and ethanol (ABE) was carried out using immobilized cells of Clostridium acetobutylicum DSM 792 using glucose and sugar mixture as a substrate. Among various lignocellulosic materials screened as a support matrix, coconut fibers and wood pulp fibers were found to be promising in batch experiments. With a motive of promoting wood-based bio-refinery concept, wood pulp was used as a cell holding material. Glucose and sugar mixture (glucose, mannose, galactose, arabinose, and xylose) comparable to lignocellulose hydrolysate was used as a substrate for continuous production of ABE. We report the best solvent productivity among wild-type strains using column reactor. The maximum total solvent concentration of 14.32 g L(-1) was obtained at a dilution rate of 0.22 h(-1) with glucose as a substrate compared to 12.64 g L(-1) at 0.5 h(-1) dilution rate with sugar mixture. The maximum solvent productivity (13.66 g L(-1) h(-1)) was obtained at a dilution rate of 1.9 h(-1) with glucose as a substrate whereas solvent productivity (12.14 g L(-1) h(-1)) was obtained at a dilution rate of 1.5 h(-1) with sugar mixture. The immobilized column reactor with wood pulp can become an efficient technology to be integrated with existing pulp mills to convert them into wood-based bio-refineries.

Water requirements of the pulp and paper industry

USGS Publications Warehouse

Mussey, Orville D.

1955-01-01

Water, of varied qualities, is used for several purposes in the manufacture of pulp and paper, as a vehicle for transporting the constituents of paper in the paper machines; as process water for cooking wood chips to make pulp; as a medium for heat transfer; and for washing the pulpwood, the woodpulp, and the machines that handle the pulp. About 3,200 million gallons of water was withdrawn from surface- and ground-water sources each day during 1950 for the use of the pulp and paper industry. This is about 4 percent of the total estimated industrial withdrawal of water in the Nation The paper industry in the United States has been growing at a rapid rate. It has increased about tenfold in the last 50 years and has doubled every 15 years. The 1950 production of paper was about 24 million tons, which amounts to about 85 percent of the domestic consumption. In 1950, the pulp mills of the country produced more than 14 million tons of woodpulp, which supplied about 85 percent of the demand by the paper mills and other industries. The remainder of the fiber for paper manufacture was obtained from imported woodpulp, from reclaimed wastepaper, and from other fibers including rags and straw. The nationwide paper consumption for 1955 has been estimated at 31,700,000 tons. Woodpulp is classified according to the process by which it is made. Every woodpulp has characteristics that are carried over into the many and diverse grades of paper. Groundwood pulp is manufactured by simply grinding up wood and refining the resulting product. Soda, sulfite, and sulfate pulps are manufactured by chemically breaking down the lignin that cements the cellulose of the wood together and removing, cleaning, and sometimes bleaching the resulting fibers. Some woodpulp is produced by other methods. Sulfate-pulp mills are increasing in number and in rated daily capacity and are manufacturing more than half of the present domestic production of woodpulp. Most of the newer and larger woodpulp mills are manufacturing sulfate pulp; because of the antipollution laws, many sulfite-pulp mills are being converted to sulfate-pulp mills. The waste from the manufacture of a ton of sulfate pulp is much more readily disposed of than that from a ton of sulfite pulp. Pulp mills are located near the source of raw material, which means that they are located in the eastern half of the United States and in the Pacific Northwest. It is advantageous for paper mills to be located close to a market and therefore a large number of paper mills are in the northeastern section of the United States from Minnesota to Maine. However, much of the coarser paper, which will ship well, is produced close to the pulp mills. The entire process of making paper from pulpwood, with special reference to water use is briefly described to provide an understanding of how the water is used and reused.

Determination of ABO blood grouping and Rhesus factor from tooth material.

PubMed

Kumar, Pooja Vijay; Vanishree, M; Anila, K; Hunasgi, Santosh; Suryadevra, Sri Sujan; Kardalkar, Swetha

2016-01-01

The aim of the study was to determine blood groups and Rhesus factor from dentin and pulp using absorption-elution (AE) technique in different time periods at 0, 3, 6, 9 and 12 months, respectively. A total of 150 cases, 30 patients each at 0, 3, 6, 9 and 12 months were included in the study. The samples consisted of males and females with age ranging 13-60 years. Patient's blood group was checked and was considered as "control." The dentin and pulp of extracted teeth were tested for the presence of ABO/Rh antigen, at respective time periods by AE technique. Data were analyzed in proportion. For comparison, Chi-square test or Fisher's exact test was used for the small sample. Blood group antigens of ABO and Rh factor were detected in dentin and pulp up to 12 months. For both ABO and Rh factor, dentin and pulp showed 100% sensitivity for the samples tested at 0 month and showed a gradual decrease in the sensitivity as time period increased. The sensitivity of pulp was better than dentin for both the blood grouping systems and ABO blood group antigens were better detected than Rh antigens. In dentin and pulp, the antigens of ABO and Rh factor were detected up to 12 months but showed a progressive decrease in the antigenicity as the time period increased. When compared the results obtained of dentin and pulp in ABO and Rh factor grouping showed similar results with no statistical significance. The sensitivity of ABO blood grouping was better than Rh factor blood grouping and showed a statistically significant result.

Properties of the "Orgamax" osteoplastic material made of a demineralized allograft bone

NASA Astrophysics Data System (ADS)

Podorognaya, V. T.; Kirilova, I. A.; Sharkeev, Yu. P.; Uvarkin, P. V.; Zhelezny, P. A.; Zheleznaya, A. P.; Akimova, S. E.; Novoselov, V. P.; Tupikova, L. N.

2016-08-01

We investigated properties of the "Orgamax" osteoplastic material, which was produced from a demineralized bone, in the treatment of extensive caries, in particular chronic pulpitis of the permanent teeth with unformed roots in children. The "Orgamax" osteoplastic material consists of demineralized bone chips, a collagen additive, and antibiotics. The surface morphology of the "Orgamax" osteoplastic material is macroporous, with the maximum pore size of 250 µm, whereas the surface morphology of the major component of "Orgamax", demineralized bone chips, is microporous, with a pore size of 10-20 µm. Material "Orgamax" is used in the treatment of complicated caries, particularly chronic pulpitis of permanent teeth with unformed roots in children. "Orgamax" filling a formed cavity exhibits antimicrobial properties, eliminates inflammation in the dental pulp, and, due to its osteoconductive and osteoinductive properties, undergoes gradual resorption, stimulates regeneration, and provides replacement of the defect with newly formed tissue. The dental pulp viability is completely restored, which ensures the complete formation of tooth roots with root apex closure in the long-term period.

Tip cap for a rotor blade

NASA Technical Reports Server (NTRS)

Kofel, W. K.; Tuley, E. N.; Gay, C. H., Jr.; Troeger, R. E.; Sterman, A. P. (Inventor)

1983-01-01

A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap.

Dental Stem Cell Migration on Pulp Ceiling Cavities Filled with MTA, Dentin Chips, or Bio-Oss

PubMed Central

Lymperi, Stefania; Taraslia, Vasiliki; Tsatsoulis, Ioannis N.; Samara, Athina; Agrafioti, Anastasia; Anastasiadou, Ema; Kontakiotis, Evangelos

2015-01-01

MTA, Bio-Oss, and dentin chips have been successfully used in endodontics. The aim of this study was to assess the adhesion and migration of dental stem cells on human pulp ceiling cavities filled with these endodontic materials in an experimental model, which mimics the clinical conditions of regenerative endodontics. Cavities were formed, by a homemade mold, on untouched third molars, filled with endodontic materials, and observed with electron microscopy. Cells were seeded on cavities' surface and their morphology and number were analysed. The phenomenon of tropism was assessed in a migration assay. All three materials demonstrated appropriate microstructures for cell attachment. Cells grew on all reagents, but they showed a differential morphology. Moreover, variations were observed when comparing cells numbers on cavity's filling versus the surrounding dentine disc. The highest number of cells was recorded on dentin chips whereas the opposite was true for Bio-Oss. This was confirmed in the migration assay where a statistically significant lower number of cells migrated towards Bio-Oss as compared to MTA and dentin chips. This study highlights that MTA and dentin chips have a greater potential compared to Bio-Oss regarding the attraction of dental stem cells and are good candidates for bioengineered pulp regeneration. PMID:26146613

Soda-Anthraquinone Durian (Durio Zibethinus Murr.) Rind Linerboard and Corrugated Medium Paper: A Preliminary Test

NASA Astrophysics Data System (ADS)

Rizal Masrol, Shaiful; Irwan Ibrahim, Mohd Halim; Adnan, Sharmiza; Mubarak Sa'adon, Amir; Ika Sukarno, Khairil; Fadrol Hisham Yusoff, Mohd

2017-08-01

A preliminary test was conducted to investigate the characteristics of linerboard and corrugated medium paper made from durian rind waste. Naturally dried durian rinds were pulped according to Soda-Anthraquinone (Soda-AQ) pulping process with a condition of 20% active alkali, 0.1% AQ, 7:1 liquor to material ratio, 120 minutes cooking time and 170°C cooking temperature. The linerboard and corrugated medium paper with a basis weight of 120 gsm were prepared and evaluated according to Malaysian International Organization for Standardization (MS ISO) and Technical Association of the Pulp and Paper Industry (TAPPI). The results indicate that the characteristics of durian rind linerboard are comparable with other wood or non-wood based paper and current commercial paper. However, low CMT value for corrugated medium and water absorptiveness quality for linerboard could be improved in future. Based on the bulk density (0.672 g/cm3), burst index (3.12 kPa.m2/g) and RCT (2.00 N.m2/g), the durian rind has shown a good potential and suitable as an alternative raw material source for linerboard industry.

Evaluation Of The Physical Stability, Ground Water Seepage Control, And Faunal Changes Associated With An AquaBlok® Sediment Cap

EPA Science Inventory

Active sediment caps are being considered for addressing contaminated sediment areas in surface-water bodies. A demonstration of an active cap designed to reduce advective transport of contaminants using AquaBlok^® (active cap material) was initiated in a small study a...

Caps Seal Boltholes On Vacuum-System Flanges

NASA Technical Reports Server (NTRS)

Roman, Robert F.

1993-01-01

Sealing caps devised for boltholes on vacuum-system flanges. Used in place of leak-prone gaskets, and provide solid metal-to-metal interfaces. Each sealing cap contains square-cut circular groove in which O-ring placed. Mounted on studs protruding into access ports, providing positive seal around each bolthole. Each cap mates directly with surface of flange, in solid metal-to-metal fit, with O-ring completely captured in groove. Assembly immune to misalignment, leakage caused by vibration, and creeping distortion caused by weight of port. O-ring material chosen for resistance to high temperature; with appropriate choice of material, temperature raised to as much as 315 degrees C.

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, packing material is placed over the nose cap that was removed from Atlantis. The reinforced carbon-carbon (RCC) nose cap is being sent to the original manufacturing company, Vought in Ft. Worth, Texas, a subsidiary of Lockheed Martin, to undergo non-destructive testing such as CAT scan and thermography.

NASA Image and Video Library

2003-10-29

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, packing material is placed over the nose cap that was removed from Atlantis. The reinforced carbon-carbon (RCC) nose cap is being sent to the original manufacturing company, Vought in Ft. Worth, Texas, a subsidiary of Lockheed Martin, to undergo non-destructive testing such as CAT scan and thermography.

Enhanced differentiation of dental pulp cells cultured on microtubular polymer scaffolds in vitro.

PubMed

Haeri, Morteza; Sagomonyants, Karen; Mina, Mina; Kuhn, Liisa T; Goldberg, A Jon

2017-06-01

Dental caries (tooth decay) is the most common chronic disease. Dental tissue engineering is a promising alternative approach to alleviate the shortcomings of the currently available restorative materials. Mimicking the natural extracellular matrix (ECM) could enhance the performance of tissue engineering scaffolds. In this study, we developed microtubular (~20 μm diameter) polymethyl methacrylate (PMMA) scaffolds resembling the tubular (~2.5 μm diameter) structure of dentin, the collagen-based mineralized tissue that forms the major portion of teeth, to study the effect of scaffold architecture on differentiation of mouse dental pulp cells in vitro . Flat (control), plasma-treated solid and microtubular PMMA scaffolds with densities of 240±15, 459±51 and 480±116 tubules/mm 2 were first characterized using scanning electron microscopy and contact angle measurements. Dental pulp cells were cultured on the surface of the scaffolds for up to 21 days and examined using various assays. Cell proliferation and mineralization were examined using Alamar Blue and Xylenol Orange (XO) staining assays, respectively. The differentiation of pulp cells into odontoblasts was examined by immunostaining for Nestin and by quantitative PCR analysis for dentin matrix protein 1 ( Dmp1 ), dentin sialophosphoprotein ( Dspp ) and osteocalcin ( Ocn ). Our results showed that the highest tubular density scaffolds significantly (p<0.05) enhanced differentiation of pulp cells into odontoblasts as compared to control flat scaffolds, as evidenced by increased expression of Nestin (5.4x). However, mineralization was suppressed on all surfaces, possibly due to low cell density. These results suggest that the microtubular architecture may be a desirable feature of scaffolds developed for clinical applications. Regenerative engineering of diseased or traumatized tooth structure could avoid the deficiencies of traditional dental restorative (filling) materials. Cells in the dental pulp have the potential to differentiate to dentin-producing odontoblast cells. Furthermore, cell-supporting scaffolds that mimic a natural extracellular matrix (ECM) are known to influence behavior of progenitor cells. Accordingly, we hypothesized that a dentin-like microtubular scaffold would enhance differentiation of dental pulp cells. The hypothesis was proven true and differentiation to odontoblasts increased with increasing density of the microtubules. However, mineralization was suppressed, possibly due to a low density of cells. The results demonstrate the potential benefits of a microtubular scaffold design to promote odontoblast cells for regeneration of dentin.

Impact of laser-contaminant interaction on the performance of the protective capping layer of 1w high-reflection mirror coatings

DOE PAGES

Qiu, S. R.; Norton, M. A.; Raman, R. N.; ...

2015-10-02

In this paper, high dielectric constant multilayer coatings are commonly used on high-reflection mirrors for high-peak-power laser systems because of their high laser-damage resistance. However, surface contaminants often lead to damage upon laser exposure, thus limiting the mirror’s lifetime and performance. One plausible approach to improve the overall mirror resistance against laser damage, including that induced by laser-contaminant coupling, is to coat the multilayers with a thin protective capping (absentee) layer on top of the multilayer coatings. An understanding of the underlying mechanism by which laser-particle interaction leads to capping layer damage is important for the rational design and selectionmore » of capping materials of high-reflection multilayer coatings. In this paper, we examine the responses of two candidate capping layer materials, made of SiO 2 and Al 2O 3, over silica-hafnia multilayer coatings. These are exposed to a single oblique shot of a 1053 nm laser beam (fluence ~10 J/cm 2, pulse length 14 ns), in the presence of Ti particles on the surface. We find that the two capping layers show markedly different responses to the laser-particle interaction. The Al 2O 3 cap layer exhibits severe damage, with the capping layer becoming completely delaminated at the particle locations. The SiO 2 capping layer, on the other hand, is only mildly modified by a shallow depression. Combining the observations with optical modeling and thermal/mechanical calculations, we argue that a high-temperature thermal field from plasma generated by the laser-particle interaction above a critical fluence is responsible for the surface modification of each capping layer. The great difference in damage behavior is mainly attributed to the large disparity in the thermal expansion coefficient of the two capping materials, with that of Al 2O 3 layer being about 15 times greater than that of SiO 2.« less

Impact of laser-contaminant interaction on the performance of the protective capping layer of 1w high-reflection mirror coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, S. R.; Norton, M. A.; Raman, R. N.

In this paper, high dielectric constant multilayer coatings are commonly used on high-reflection mirrors for high-peak-power laser systems because of their high laser-damage resistance. However, surface contaminants often lead to damage upon laser exposure, thus limiting the mirror’s lifetime and performance. One plausible approach to improve the overall mirror resistance against laser damage, including that induced by laser-contaminant coupling, is to coat the multilayers with a thin protective capping (absentee) layer on top of the multilayer coatings. An understanding of the underlying mechanism by which laser-particle interaction leads to capping layer damage is important for the rational design and selectionmore » of capping materials of high-reflection multilayer coatings. In this paper, we examine the responses of two candidate capping layer materials, made of SiO 2 and Al 2O 3, over silica-hafnia multilayer coatings. These are exposed to a single oblique shot of a 1053 nm laser beam (fluence ~10 J/cm 2, pulse length 14 ns), in the presence of Ti particles on the surface. We find that the two capping layers show markedly different responses to the laser-particle interaction. The Al 2O 3 cap layer exhibits severe damage, with the capping layer becoming completely delaminated at the particle locations. The SiO 2 capping layer, on the other hand, is only mildly modified by a shallow depression. Combining the observations with optical modeling and thermal/mechanical calculations, we argue that a high-temperature thermal field from plasma generated by the laser-particle interaction above a critical fluence is responsible for the surface modification of each capping layer. The great difference in damage behavior is mainly attributed to the large disparity in the thermal expansion coefficient of the two capping materials, with that of Al 2O 3 layer being about 15 times greater than that of SiO 2.« less

Properties of foam and composite materials made o starch and cellulose fiber

USDA-ARS?s Scientific Manuscript database

Composite materials were made of starch and cellulose fibers. Pre-gelatinized starch was effective in dispersing pulp fiber in a starch matrix to form a viscous starch/fiber dough. The starch/fiber dough was a useful feedstock for various composite foam and plastic materials. Viscous blends of star...

Production of porous Calcium Phosphate (CaP) ceramics with aligned pores using ceramic/camphene-based co-extrusion.

PubMed

Choi, Won-Young; Kim, Hyoun-Ee; Moon, Young-Wook; Shin, Kwan-Ha; Koh, Young-Hag

2015-01-01

Calcium phosphate (CaP) ceramics are one of the most valuable biomaterials for uses as the bone scaffold owing to their outstanding biocompatability, bioactivity, and biodegradation nature. In particular, these materials with an open porous structure can stimulate bone ingrowth into their 3-dimensionally interconnected pores. However, the creation of pores in bulk materials would inevitably cause a severe reduction in mechanical properties. Thus, it is a challenge to explore new ways of improving the mechanical properties of porous CaP scaffolds without scarifying their high porosity. Porous CaP ceramic scaffolds with aligned pores were successfully produced using ceramic/camphene-based co-extrusion. This aligned porous structure allowed for the achievement of high compressive strength when tested parallel to the direction of aligned pores. In addition, the overall porosity and mechanical properties of the aligned porous CaP ceramic scaffolds could be tailored simply by adjusting the initial CaP content in the CaP/camphene slurry. The porous CaP scaffolds showed excellent in vitro biocompatibility, suggesting their potential as the bone scaffold. Aligned porous CaP ceramic scaffolds with considerably enhanced mechanical properties and tailorable porosity would find very useful applications as the bone scaffold.

Stem/progenitor cells from inflamed human dental pulp retain tissue regeneration potential

PubMed Central

Alongi, Dominick J; Yamaza, Takayoshi; Song, Yingjie; Fouad, Ashraf F; Romberg, Elaine E; Shi, Songtao; Tuan, Rocky S; Huang, George T-J

2011-01-01

Background Potent stem/progenitor cells have been isolated from normal human dental pulps termed dental pulp stem cells (DPSCs). However, it is unknown whether these cells exist in inflamed pulps (IPs). Aims To determine whether DPSCs can be identified and isolated from IPs; and if they can be successfully cultured, whether they retain tissue regeneration potential in vivo. Materials & methods DPSCs from freshly collected normal pulps (NPs) and IPs were characterized in vitro and their tissue regeneration potential tested using an in vivo study model. Results The immunohistochemical analysis showed that IPs expressed higher levels of mesenchymal stem cell markers STRO-1, CD90, CD105 and CD146 compared with NPs (p < 0.05). Flow cytometry analysis showed that DPSCs from both NPs and IPs expressed moderate to high levels of CD146, stage-specific embryonic antigen-4, CD73 and CD166. Total population doubling of DPSCs-IPs (44.6 ± 2.9) was lower than that of DPSCs-NPs (58.9 ± 2.5) (p < 0.05), and DPSCs-IPs appeared to have a decreased osteo/dentinogenic potential compared with DPSCs-NPs based on the mineral deposition in cultures. Nonetheless, DPSCs-IPs formed pulp/dentin complexes similar to DPSCs-NPs when transplanted into immunocompromised mice. Conclusion DPSCs-IPs can be isolated and their mesenchymal stem cell marker profiles are similar to those from NPs. Although some stem cell properties of DPSCs-IPs were altered, cells from some samples remained potent in tissue regeneration in vivo. PMID:20465527

A comparative study of internally and externally capped balloons using small scale test balloons

NASA Technical Reports Server (NTRS)

Bell, Douglas P.

1994-01-01

Caps have been used to structurally reinforce scientific research balloons since the late 1950's. The scientific research balloons used by the National Aeronautics and Space Administration (NASA) use internal caps. A NASA cap placement specification does not exist since no empirical information exisits concerning cap placement. To develop a cap placement specification, NASA has completed two in-hangar inflation tests comparing the structural contributions of internal caps and external caps. The tests used small scale test balloons designed to develop the highest possible stresses within the constraints of the hangar and balloon materials. An externally capped test balloon and an internally capped test balloon were designed, built, inflated and simulated to determine the structural contributions and benefits of each. The results of the tests and simulations are presented.

Improvement in rice straw pulp bleaching effluent quality by incorporating oxygen delignification stage prior to elemental chlorine-free bleaching.

PubMed

Kaur, Daljeet; Bhardwaj, Nishi K; Lohchab, Rajesh Kumar

2017-10-01

Environmental degradation by industrial and other developmental activities is alarming for imperative environmental management by process advancements of production. Pulp and paper mills are now focusing on using nonwood-based raw materials to protect forest resources. In present study, rice straw was utilized for pulp production as it is easily and abundantly available as well as rich in carbohydrates (cellulose and hemicelluloses). Soda-anthraquinone method was used for pulp production as it is widely accepted for agro residues. Bleaching process during paper production is the chief source of wastewater generation. The chlorophenolic compounds generated during bleaching are highly toxic, mutagenic, and bioaccumulative in nature. The objectives of study were to use oxygen delignification (ODL) stage prior to elemental chlorine-free (ECF) bleaching to reduce wastewater load and to study its impact on bleached pulp characteristics. ODL stage prior to ECF bleaching improved the optical properties of pulp in comparison to only ECF bleaching. When ODL stage was incorporated prior to bleaching, the tensile index and folding endurance of the pulp were found to be 56.6 ± 1.5 Nm/g and 140, respectively, very high in comparison to ECF alone. A potential reduction of 51, 57, 43, and 53% in BOD 3 , COD, color, and AOX, respectively was observed on adding the ODL stage compared to ECF only. Generation of chlorophenolic compounds was reduced significantly. Incorporation of ODL stage prior to bleaching was found to be highly promising for reducing the toxicity of bleaching effluents and may lead to better management of nearby water resources. Graphical abstract ᅟ.

The Experimental Study of the Performance of Nano-Thin Polyelectrolyte Shell for Dental Pulp Stem Cells Immobilization.

PubMed

Grzeczkowicz, A; Granicka, L H; Maciejewska, I; Strawski, M; Szklarczyk, M; Borkowska, M

2015-12-01

Carious is the most frequent disease of mineralized dental tissues which might result in dental pulp inflammation and mortality. In such cases an endodontic treatment is the only option to prolong tooth functioning in the oral cavity; however, in the cases of severe pulpitis, especially when complicated with periodontal tissue inflammation, the endodontic treatment might not be enough to protect against tooth loss. Thus, keeping the dental pulp viable and/or possibility of the reconstruction of a viable dental pulp complex, appears to become a critical factor for carious and/or pulp inflammation treatment. The nowadays technologies, which allow handling dental pulp stem cells (DPSC), seem to bring us closer to the usage of dental stem cells for tooth tissues reconstruction. Thus, DPSC immobilized within nano-thin polymeric shells, allowing for a diffusion of produced factors and separation from bacteria, may be considered as a cover system supporting technology of dental pulp reconstruction. The DPSC were immobilized using a layer-by-layer technique within nano-thin polymeric shells constructed and modified by nanostructure involvement to ensure the layers stability and integrity as well as separation from bacterial cells. The cytotoxity of the material used for membrane production was assessed on the model of adherent cells. The performance of DPSC nano-coating was assessed in vitro. Membrane coatings showed no cytotoxicity on the immobilized cells. The presence of coating shell was confirmed with flow cytometry, atomic force microscopy and visualized with fluorescent microscopy. The transfer of immobilized DPSC within the membrane system ensuring cells integrity, viability and protection from bacteria should be considered as an alternative method for dental tissues transportation and regeneration.

Section 2: Corrosion and failure analysis studies in support of the pulp and paper industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keiser, J.R.; Pawel, S.J.; Swindeman, R.W.

1997-04-01

Technical support is being provided to various pulp and paper companies and related industries to help determine the cause of material degradation problems and to identify alternate materials to prevent such degradation. During the past year, examinations have included parts from several sootblowers, two failed economizer tubes, and inspection of a continuous digester. The results of the analyses and inspections were communicated to the plant operators, and, in some cases, recommendations were made. This article discusses examination of sootblower nozzles, which evidenced intergranular cracking. Analysis indicated the presence of chromium carbide precipitates along the grain boundaries, which can cause themore » sample to be sensitized to grain boundary attack.« less

Pulp/tooth ratio of mandibular first and second molars on panoramic radiographs: An aid for forensic age estimation

PubMed Central

Shah, Palak H.; Venkatesh, Rashmi

2016-01-01

Objective: To determine and compare the accuracy of pulp/tooth ratio method in mandibular first and second molar teeth in forensic age estimation. Materials and Methods: A total 300 panoramic radiographs of the Gujarati population (187 males and 113 females) were studied. The measurements of Pulp Chamber Height (PCH) and Crown Root Trunk Height (CRTH) were performed on the mandibular first and second molar teeth. The acquired data was subjected to correlation and regression. Results: The pulp chamber crown root trunk height ratios (PCTHR) of both the first (r = −0.609) and second molars (r = −0.422) were significantly correlated with the age of the individual. Individual regression formulae were derived for both the teeth which were then used separately to calculate the age. The standard errors estimate (SEE) for the first and second molars were 8.84 years and 10.11 years, respectively. There was no statistically significant difference between chronological and calculated age by both the teeth (P = 1.000). Conclusion: The mandibular first and second molar is a potential tool for age estimation in forensic dentistry. The pulp/tooth ratio of both the teeth is a useful method for forensic age prediction with reasonable accuracy in the Gujarati population. PMID:27555734

Crystallographic Texture and Elemental Composition Mapped in Bovine Root Dentin at the 200 nm Level

PubMed Central

Deymier-Black, A. C.; Veis, A.; Cai, Z.; Stock, S. R.

2015-01-01

Summary The relationship between the mineralization of peritubular dentin (PTD) and intertubular dentin (ITD) is not well understood. Tubules are quite small, diameter ~2 μm, and this makes the near-tubule region of dentin difficult to study. Here, advanced characterization techniques are applied in a novel way to examine what organic or nanostructural signatures may indicate the end of ITD or the beginning of PTD mineralization. X-ray fluorescence intensity (Ca, P, and Zn) and X-ray diffraction patterns from carbonated apatite (cAp) were mapped around dentintubules at resolutions ten times smaller than the feature size (200 nm pixels), representing a 36% increase in resolution over earlier work. In the near tubule volumes of near-pulp, root dentin, Zn intensity was higher than in ITD remote from the tubules. This increase in Zn2+, as determined by X-ray absorption near edge structure analysis, may indicate the presence of metalloenzymes or transcription factors important to ITD or PTD mineralization. The profiles of the cAp 00.2 X-ray diffraction rings were fitted with a pseudo-Voigt function, and the spatial and azimuthal distribution of these rings’ integrated intensities indicated that the cAp platelets were arranged with their c-axes aligned tangential to the edge of the tubule lumen. This texture was continuous throughout the dentin indicating a lack of structural difference between in the Zn rich near-tubular region and the remote ITD. PMID:23630059

Articaine and mepivacaine buccal infiltration in securing mandibular first molar pulp anesthesia following mepivacaine inferior alveolar nerve block: A randomized, double-blind crossover study

PubMed Central

Gazal, Giath; Alharbi, Abdullah Muteb; Al-Samadani, Khalid HidayatAllah; Kanaa, Mohammad Dib

2015-01-01

Aims: A crossover double-blind, randomized study was designed to explore the efficacy of 2% mepivacaine with 1:100,000 adrenaline buccal infiltration and 4% articaine with 1:100,000 adrenaline buccal infiltration following 2% mepivacaine with 1:100,000 adrenaline inferior alveolar nerve block (IANB) for testing pulp anesthesia of mandibular first molar teeth in adult volunteers. Materials and Methods: A total of 23 healthy adult volunteers received two regimens with at least 1-week apart; one with 4% articaine buccal infiltration and 2% mepivacaine IANB (articaine regimen) and another with 2% mepivacaine buccal infiltration supplemented to 2% mepivacaine IANB (mepivacaine regimen). Pulp testing of first molar tooth was electronically measured twice at baseline, then at intervals of 2 min for the first 10 min, then every 5 min until 45 min postinjection. Anesthetic success was considered when two consecutive maximal stimulation on pulp testing readings without sensation were obtained within 10 min and continuously sustained for 45 min postinjection. Results: In total, the number of no sensations to maximum pulp testing for first molar teeth were significantly higher after articaine regimen than mepivacaine during 45 min postinjection (267 vs. 250 episodes, respectively, P < 0.001), however, both articaine and mepivacaine buccal infiltrations are equally effective in securing anesthetic success for first molar pulp anesthesia when supplemented to mepivacaine IANB injections (P > 0.05). Interestingly, volunteers in the articaine regimen provided faster onset and longer duration (means 2.78 min, 42.22 min, respectively) than mepivacaine regimen (means 4.26 min, 40.74 min, respectively) for first molar pulp anesthesia (P < 0.001). Conclusions: Supplementary mepivacaine and articaine buccal infiltrations produced similar successful first molar pulp anesthesia following mepivacaine IANB injections in volunteers. Articaine buccal infiltration produced faster onset and longer duration than mepivacaine buccal infiltration following mepivacaine IANB injections. PMID:26543456

Design and implementation of the protective cap/biobarrier experiment at the Idaho National Engineering Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Limbach, W.E.; Ratzlaff, T.D.; Anderson, J.E.

1994-12-31

The Protective Cap/Biobarrier Experiment (PCBE), initiated in 1993 at the Idaho National Engineering Laboratory (INEL), is a strip-split plot experiment with three replications designed to rigorously test a 2.0-m loessal soil cap against a cap recommended by the US Environmental Protection Agency and two caps with biological intrusion barriers. Past research at INEL indicates that it should be possible to exclude water from buried wastes using natural materials and natural processes in arid environments rather than expensive materials (geotextiles) and highly engineered caps. The PCBE will also test the effects of two vegetal covers and three irrigation levels on capmore » performance. Drainage pans, located at the bottom of each plot, will monitor cap failure. Soil water profiles will be monitored biweekly by neutron probe and continuously by time domain reflectometry. The performance of each cap design will be monitored under a variety of conditions through 1998. From 1994 to 1996, the authors will assess plant establishment, rooting depths, patterns of moisture extraction and their interactions among caps, vegetal covers, and irrigation levels. In 1996, they will introduce ants and burrowing mammals to test the structural integrity of each cap design. In 1998, the authors will apply sufficient water to determine the failure limit for each cap design. The PCBE should provide reliable knowledge of the performances of the four cap designs under a variety of conditions and aid in making hazardous-waste management decisions at INEL and at disposal sites in similar environments.« less

27 CFR 24.243 - Filtering aids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... fibers, pulps, earths, or similar materials, may be used as filtering aids in the cellar treatment and finishing of wine. Agar-agar, carrageenan, cellulose, and diatomaceous earth are commonly employed inert... records need be maintained concerning their use. However, if the inert material is dissolved in water...

27 CFR 24.243 - Filtering aids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... fibers, pulps, earths, or similar materials, may be used as filtering aids in the cellar treatment and finishing of wine. Agar-agar, carrageenan, cellulose, and diatomaceous earth are commonly employed inert... records need be maintained concerning their use. However, if the inert material is dissolved in water...

27 CFR 24.243 - Filtering aids.

Code of Federal Regulations, 2014 CFR

2014-04-01

... fibers, pulps, earths, or similar materials, may be used as filtering aids in the cellar treatment and finishing of wine. Agar-agar, carrageenan, cellulose, and diatomaceous earth are commonly employed inert... records need be maintained concerning their use. However, if the inert material is dissolved in water...

Development of an easy-debonding orthodontic adhesive using thermal heating.

PubMed

Tsuruoka, Takashi; Namura, Yasuhiro; Shimizu, Noriyoshi

2007-01-01

We produced experimentally a new bonding material that consisted of a mixture of a base resin (4-META/MMA-TBB resin adhesive) and thermoexpandable microcapsules for safe, easy debonding. Microcapsules in the base resin would start expansion at 80 degrees C, leading to a remarkable decrease in bond strength. Stainless steel brackets were bonded to bovine permanent mandibular incisors using bonding materials containing the microcapsules at different contents. After thermal cycling or heating, the shear bond strength of the brackets was measured. Shear bond strength of the bonding materials containing 30-40 wt% microcapsules decreased to about one-third or one-fifth that of the base resin on heating. Heating the brackets for eight seconds increased the temperature in the pulp chamber by 2 degrees C, which should not induce pulp damage. Results obtained suggested that the new bonding material should prove useful for removing brackets easily at the time of bracket debonding without any pain or enamel cracks, while maintaining the bonding strength during active orthodontic treatment.

Interaction of Substrate Mechanics with Dental Pulp Stem Cells (DPSCs) differentiation to generate a scaffold for Bone regeneration

NASA Astrophysics Data System (ADS)

Rafailovich, Miriam; Bhatnagar, Divya; Bherwani, Aneel; Simon, Marcia

2012-02-01

This work investigates the interaction of the substrate mechanics with the differentiation in the absence of chemical induction and only resulting from the stimuli of the substrate mechanics and chemistry. We chose enzymatically cross-linked gelatin hydrogels substrates of different stiffness varying from 8KPa to 100Pa. DPSCs were cultured and differentiated on the substrates for 7, 14 and 21 days with and without dexamethasone induction media. SEM and EDX analysis after 21 days indicate that cells produced a sheet of biomineralized deposits, several tenths of mm thick on the hard substrate irrespective of chemical induction. Modulli of the cells was independent of the induction and stiffness of the hydrogels. RT-PCR assays indicated that cells expressed more osteocalcin when cultured in non-induction media and harder substrate. The shape of the deposits was more uniform and in close packing on the harder substrate with a higher Ca:P ratio. On soft substrate the deposits were more flat with less Ca:P ratio. Further experiments indicated that conformational change due to the crosslinking of gelatin could be the reason for biomineralization.

A review of the regenerative endodontic treatment procedure

PubMed Central

Lee, Bin-Na; Moon, Jong-Wook; Chang, Hoon-Sang; Hwang, In-Nam; Oh, Won-Mann

2015-01-01

Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure designed to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment. PMID:26295020

Bacterial profile in primary teeth with necrotic pulp and periapical lesions.

PubMed

da Silva, Léa Assed Bezerra; Nelson-Filho, Paulo; Faria, Gisele; de Souza-Gugelmin, Maria Cristina Monteiro; Ito, Izabel Yoko

2006-01-01

The objective of this study was to evaluate the bacterial profile in root canals of human primary teeth with necrotic pulp and periapical lesions using bacterial culture. A total of 20 primary teeth with necrotic pulp and radiographically visible radiolucent areas in the region of the bone furcation and/or the periapical region were selected. After crown access, 4 sterile absorbent paper points were introduced sequentially into the root canal for collection of material. After 30 s, the paper points were removed and placed in a test tube containing reduced transport fluid (RTF) and were sent for microbiological evaluation. Anaerobic microorganisms were found in 100% of the samples, black-pigmented bacilli in 30%, aerobic microorganisms in 60%, streptococci in 85%, gram-negative aerobic rods in 15% and staphylococci were not quantified. Mutans streptococci were found in 6 root canals (30%), 5 canals with Streptococcus mutans and 1 canal with Streptococcus mutans and Streptococcus sobrinus. It was concluded that in root canals of human primary teeth with necrotic pulp and periapical lesions, the infection is polymicrobial with predominance of anaerobic microorganisms.

Secondary environmental impacts of remedial alternatives for sediment contaminated with hydrophobic organic contaminants.

PubMed

Choi, Yongju; Thompson, Jay M; Lin, Diana; Cho, Yeo-Myoung; Ismail, Niveen S; Hsieh, Ching-Hong; Luthy, Richard G

2016-03-05

This study evaluates secondary environmental impacts of various remedial alternatives for sediment contaminated with hydrophobic organic contaminants using life cycle assessment (LCA). Three alternatives including two conventional methods, dredge-and-fill and capping, and an innovative sediment treatment technique, in-situ activated carbon (AC) amendment, are compared for secondary environmental impacts by a case study for a site at Hunters Point Shipyard, San Francisco, CA. The LCA results show that capping generates substantially smaller impacts than dredge-and-fill and in-situ amendment using coal-based virgin AC. The secondary impacts from in-situ AC amendment can be reduced effectively by using recycled or wood-based virgin AC as production of these materials causes much smaller impacts than coal-based virgin AC. The secondary environmental impacts are highly sensitive to the dredged amount and the distance to a disposal site for dredging, the capping thickness and the distance to the cap materials for capping, and the AC dose for in-situ AC amendment. Based on the analysis, this study identifies strategies to minimize secondary impacts caused by different remediation activities: optimize the dredged amount, the capping thickness, or the AC dose by extensive site assessments, obtain source materials from local sites, and use recycled or bio-based AC. Copyright © 2015 Elsevier B.V. All rights reserved.

Regeneration and Repair in Endodontics—A Special Issue of the Regenerative Endodontics—A New Era in Clinical Endodontics

PubMed Central

Saoud, Tarek Mohamed A.; Ricucci, Domenico; Lin, Louis M.; Gaengler, Peter

2016-01-01

Caries is the most common cause of pulp-periapical disease. When the pulp tissue involved in caries becomes irreversibly inflamed and progresses to necrosis, the treatment option is root canal therapy because the infected or non-infected necrotic pulp tissue in the root canal system is not accessible to the host's innate and adaptive immune defense mechanisms and antimicrobial agents. Therefore, the infected or non-infected necrotic pulp tissue must be removed from the canal space by pulpectomy. As our knowledge in pulp biology advances, the concept of treatment of pulpal and periapical disease also changes. Endodontists have been looking for biologically based treatment procedures, which could promote regeneration or repair of the dentin-pulp complex destroyed by infection or trauma for several decades. After a long, extensive search in in vitro laboratory and in vivo preclinical animal experiments, the dental stem cells capable of regenerating the dentin-pulp complex were discovered. Consequently, the biological concept of ‘regenerative endodontics’ emerged and has highlighted the paradigm shift in the treatment of immature permanent teeth with necrotic pulps in clinical endodontics. Regenerative endodontics is defined as biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as the pulp-dentin complex. According to the American Association of Endodontists’ Clinical Considerations for a Regenerative Procedure, the primary goal of the regenerative procedure is the elimination of clinical symptoms and the resolution of apical periodontitis. Thickening of canal walls and continued root maturation is the secondary goal. Therefore, the primary goal of regenerative endodontics and traditional non-surgical root canal therapy is the same. The difference between non-surgical root canal therapy and regenerative endodontic therapy is that the disinfected root canals in the former therapy are filled with biocompatible foreign materials and the root canals in the latter therapy are filled with the host's own vital tissue. The purpose of this article is to review the potential of using regenerative endodontic therapy for human immature and mature permanent teeth with necrotic pulps and/or apical periodontitis, teeth with persistent apical periodontitis after root canal therapy, traumatized teeth with external inflammatory root resorption, and avulsed teeth in terms of elimination of clinical symptoms and resolution of apical periodontitis. PMID:29563445

Regeneration and Repair in Endodontics-A Special Issue of the Regenerative Endodontics-A New Era in Clinical Endodontics.

PubMed

Saoud, Tarek Mohamed A; Ricucci, Domenico; Lin, Louis M; Gaengler, Peter

2016-02-27

Caries is the most common cause of pulp-periapical disease. When the pulp tissue involved in caries becomes irreversibly inflamed and progresses to necrosis, the treatment option is root canal therapy because the infected or non-infected necrotic pulp tissue in the root canal system is not accessible to the host's innate and adaptive immune defense mechanisms and antimicrobial agents. Therefore, the infected or non-infected necrotic pulp tissue must be removed from the canal space by pulpectomy. As our knowledge in pulp biology advances, the concept of treatment of pulpal and periapical disease also changes. Endodontists have been looking for biologically based treatment procedures, which could promote regeneration or repair of the dentin-pulp complex destroyed by infection or trauma for several decades. After a long, extensive search in in vitro laboratory and in vivo preclinical animal experiments, the dental stem cells capable of regenerating the dentin-pulp complex were discovered. Consequently, the biological concept of 'regenerative endodontics' emerged and has highlighted the paradigm shift in the treatment of immature permanent teeth with necrotic pulps in clinical endodontics. Regenerative endodontics is defined as biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as the pulp-dentin complex. According to the American Association of Endodontists' Clinical Considerations for a Regenerative Procedure, the primary goal of the regenerative procedure is the elimination of clinical symptoms and the resolution of apical periodontitis. Thickening of canal walls and continued root maturation is the secondary goal. Therefore, the primary goal of regenerative endodontics and traditional non-surgical root canal therapy is the same. The difference between non-surgical root canal therapy and regenerative endodontic therapy is that the disinfected root canals in the former therapy are filled with biocompatible foreign materials and the root canals in the latter therapy are filled with the host's own vital tissue. The purpose of this article is to review the potential of using regenerative endodontic therapy for human immature and mature permanent teeth with necrotic pulps and/or apical periodontitis, teeth with persistent apical periodontitis after root canal therapy, traumatized teeth with external inflammatory root resorption, and avulsed teeth in terms of elimination of clinical symptoms and resolution of apical periodontitis.

Advances in synthesis of calcium phosphate crystals with controlled size and shape.

PubMed

Lin, Kaili; Wu, Chengtie; Chang, Jiang

2014-10-01

Calcium phosphate (CaP) materials have a wide range of applications, including biomaterials, adsorbents, chemical engineering materials, catalysts and catalyst supports and mechanical reinforcements. The size and shape of CaP crystals and aggregates play critical roles in their applications. The main inorganic building blocks of human bones and teeth are nanocrystalline CaPs; recently, much progress has been made in the application of CaP nanocrystals and their composites for clinical repair of damaged bone and tooth. For example, CaPs with special micro- and nanostructures can better imitate the biomimetic features of human bone and tooth, and this offers significantly enhanced biological performances. Therefore, the design of CaP nano-/microcrystals, and the shape and hierarchical structures of CaPs, have great potential to revolutionize the field of hard tissue engineering, starting from bone/tooth repair and augmentation to controlled drug delivery devices. Previously, a number of reviews have reported the synthesis and properties of CaP materials, especially for hydroxyapatite (HAp). However, most of them mainly focused on the characterizations and physicochemical and biological properties of HAp particles. There are few reviews about the control of particle size and size distribution of CaPs, and in particular the control of nano-/microstructures on bulk CaP ceramic surfaces, which is a big challenge technically and may have great potential in tissue engineering applications. This review summarizes the current state of the art for the synthesis of CaP crystals with controlled sizes from the nano- to the macroscale, and the diverse shapes including the zero-dimensional shapes of particles and spheres, the one-dimensional shapes of rods, fibers, wires and whiskers, the two-dimensional shapes of sheets, disks, plates, belts, ribbons and flakes and the three-dimensional (3-D) shapes of porous, hollow, and biomimetic structures similar to biological bone and tooth. In addition, this review will also summarize studies on the controlled formation of nano-/microstructures on the surface of bulk ceramics, and the preparation of macroscopical bone grafts with 3-D architecture nano-/microstructured surfaces. Moreover, the possible directions of future research and development in this field, such as the detailed mechanisms behind the size and shape control in various strategies, the importance of theoretical simulation, self-assembly, biomineralization and sacrificial precursor strategies in the fabrication of biomimetic bone-like and enamel-like CaP materials are proposed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Air stripping-UASB process for the treatment of evaporator condensate from a Kraft pulp mill].

PubMed

Zhou, Wei-li; Qin, Xiao-peng; Yu, Jun; Imai, Tsuyoshi; Ukita, Masao

2006-04-01

Evaporator condensate from a kraft pulp mill is characterized by high temperature, high strength, poor nutrition, and some odor and inhibitive materials. In this study, air stripping-UASB process was developed to treat the wastewater from a kraft pulp mill. The lab scale study demonstrated that air stripping process removed 70%-80% of the volatile organic sulfur compounds. After that, the UASB reactor showed high efficiency, at the organic loading rate (COD) of 30 kg x (m3 x d)(-1), COD removal was retained about 95%. On the other hand, the inoculated granules were broken in the new surroundings and were replaced with the newly formed granules The scanning electronic microscope (SEM) observation showed wide difference of the predominant anaerobic microorganisms in the seed and newly formed granules.

Evaluation of a new pulping technology for pre-treating source-separated organic household waste prior to anaerobic digestion.

PubMed

Naroznova, Irina; Møller, Jacob; Larsen, Bjarne; Scheutz, Charlotte

2016-04-01

A new technology for pre-treating source-separated organic household waste prior to anaerobic digestion was assessed, and its performance was compared to existing alternative pre-treatment technologies. This pre-treatment technology is based on waste pulping with water, using a specially developed screw mechanism. The pre-treatment technology rejects more than 95% (wet weight) of non-biodegradable impurities in waste collected from households and generates biopulp ready for anaerobic digestion. Overall, 84-99% of biodegradable material (on a dry weight basis) in the waste was recovered in the biopulp. The biochemical methane potential for the biopulp was 469 ± 7 mL CH4/g ash-free mass. Moreover, all Danish and European Union requirements regarding the content of hazardous substances in biomass intended for land application were fulfilled. Compared to other pre-treatment alternatives, the screw-pulping technology showed higher biodegradable material recovery, lower electricity consumption and comparable water consumption. The higher material recovery achieved with the technology was associated with greater transfer of nutrients (N and P), carbon (total and biogenic) but also heavy metals (except Pb) to the produced biomass. The data generated in this study could be used for the environmental assessment of the technology and thus help in selecting the best pre-treatment technology for source separated organic household waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

Durability of Capped Wood Plastic Composites

Treesearch

Mark Mankowski; Mark J. Manning; Damien P. Slowik

2015-01-01

Manufacturers of wood plastic composites (WPCs) have recently introduced capped decking to their product lines. These new materials have begun to take market share from the previous generation of uncapped products that possessed a homogenous composition throughout the thickness of their cross-section. These capped offerings have been introduced with claims that the...

Organic-Inorganic Nanostructure Architecture via Directly Capping Fullerenes onto Quantum Dots.

PubMed

Lee, Jae Kwan; Kim, Jonggi; Yang, Changduk

2011-12-01

A new form of fullerene-capped CdSe nanoparticles (PCBA-capped CdSe NPs), using carboxylate ligands with [60]fullerene capping groups that provides an effective synthetic methodology to attach fullerenes noncovalently to CdSe, is presented for usage in nanotechnology and photoelectric fields. Interestingly, either the internal charge transfer or the energy transfer in the hybrid material contributes to photoluminescence (PL) quenching of the CdSe moieties.

Feasibility of 3D printed air slab diode caps for small field dosimetry.

PubMed

Perrett, Benjamin; Charles, Paul; Markwell, Tim; Kairn, Tanya; Crowe, Scott

2017-09-01

Commercial diode detectors used for small field dosimetry introduce a field-size-dependent over-response relative to an ideal, water-equivalent dosimeter due to high density components in the body of the detector. An air gap above the detector introduces a field-size-dependent under-response, and can be used to offset the field-size-dependent detector over-response. Other groups have reported experimental validation of caps containing air gaps for use with several types of diodes in small fields. This paper examines two designs for 3D printed diode air caps for the stereotactic field diode (SFD)-a cap containing a sealed air cavity, and a cap with an air cavity at the face of the SFD. Monte Carlo simulations of both designs were performed to determine dimensions for an air cavity to introduce the desired dosimetric correction. Various parameter changes were also simulated to estimate the dosimetric uncertainties introduced by 3D printing. Cap layer dimensions, cap density changes due to 3D printing, and unwanted air gaps were considered. For the sealed design the optimal air gap size for water-equivalent cap material was 0.6 mm, which increased to 1.0 mm when acrylonitrile butadiene styrene in the cap was simulated. The unsealed design had less variation, a 0.4 mm air gap is optimal in both situations. Unwanted air pockets in the bore of the cap and density changes introduced by the 3D printing process can potentially introduce significant dosimetric effects. These effects may be limited by using fine print resolutions and minimising the volume of cap material.

Establishing the 3-D finite element solid model of femurs in partial by volume rendering.

PubMed

Zhang, Yinwang; Zhong, Wuxue; Zhu, Haibo; Chen, Yun; Xu, Lingjun; Zhu, Jianmin

2013-01-01

It remains rare to report three-dimensional (3-D) finite element solid model of femurs in partial by volume rendering method, though several methods of femoral 3-D finite element modeling are already available. We aim to analyze the advantages of the modeling method by establishing the 3-D finite element solid model of femurs in partial by volume rendering. A 3-D finite element model of the normal human femurs, made up of three anatomic structures: cortical bone, cancellous bone and pulp cavity, was constructed followed by pretreatment of the CT original image. Moreover, the finite-element analysis was carried on different material properties, three types of materials given for cortical bone, six assigned for cancellous bone, and single for pulp cavity. The established 3-D finite element of femurs contains three anatomical structures: cortical bone, cancellous bone, and pulp cavity. The compressive stress primarily concentrated in the medial surfaces of femur, especially in the calcar femorale. Compared with whole modeling by volume rendering method, the 3-D finite element solid model created in partial is more real and fit for finite element analysis. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Application of high-speed photography to chip refining

NASA Astrophysics Data System (ADS)

Stationwala, Mustafa I.; Miller, Charles E.; Atack, Douglas; Karnis, A.

1991-04-01

Several high speed photographic methods have been employed to elucidate the mechanistic aspects of producing mechanical pulp in a disc refiner. Material flow patterns of pulp in a refmer were previously recorded by means of a HYCAM camera and continuous lighting system which provided cine pictures at up to 10,000 pps. In the present work an IMACON camera was used to obtain several series of high resolution, high speed photographs, each photograph containing an eight-frame sequence obtained at a framing rate of 100,000 pps. These high-resolution photographs made it possible to identify the nature of the fibrous material trapped on the bars of the stationary disc. Tangential movement of fibre floes, during the passage of bars on the rotating disc over bars on the stationary disc, was also observed on the stator bars. In addition, using a cinestroboscopic technique a large number of high resolution pictures were taken at three different positions of the rotating disc relative to the stationary disc. These pictures were computer analyzed, statistically, to determine the fractional coverage of the bars of the stationary disc with pulp. Information obtained from these studies provides new insights into the mechanism of the refining process.

Seaweed Fortification on Crispy Enbal as Local Food of Kei Islands

NASA Astrophysics Data System (ADS)

Marasabessy, Ismael; Sudirjo, Fien

2017-10-01

One of health problems phenomenon in Indonesian and the world is increasing the degenerative disease because human’s bad habits of eating that having less fiber. Source of fiber which is relatively abundant in eastern Indonesia is seaweed that is very precise to fortified on local food that aims to be more nutritious and economically valuable. The purpose of this study is to got appropriate seaweed fortification technique to produce Seaweed Crispy Enbal (SCE) as typical food from Kei islands that rich in fiber and preferred by consumers. The research was done in two stages. The first stage is to analyze quality of fiber and HCN content of seaweed and enbal flour as SCE raw material, and the two-stage is fortified fiber to enbal lempeng using two types of raw materials, namely pulp seaweed and flour seaweed. The results showed that the fiber content of seaweed Eucheuma cottonii and flour enbal respectively 7.01% and 4%, while HCN content less than 3 mg/kg. Fortification techniques using pulp seaweed better than others. It is because pulp seaweed produces seaweed crispy enbal with high value of sensory (really like) with having fiber content is 7.48%.

Decomposition and carbon storage of selected paper products in laboratory-scale landfills.

PubMed

Wang, Xiaoming; De la Cruz, Florentino B; Ximenes, Fabiano; Barlaz, Morton A

2015-11-01

The objective of this study was to measure the anaerobic biodegradation of different types of paper products in laboratory-scale landfill reactors. The study included (a) measurement of the loss of cellulose, hemicellulose, organic carbon, and (b) measurement of the methane yields for each paper product. The test materials included two samples each of newsprint (NP), copy paper (CP), and magazine paper (MG), and one sample of diaper (DP). The methane yields, carbon storage factors and the extent of cellulose and hemicellulose decomposition all consistently show that papers made from mechanical pulps (e.g., NPs) are less degradable than those made from chemical pulps where essentially all lignin was chemically removed (e.g., CPs). The diaper, which is not only made from chemical pulp but also contains some gel and plastic, exhibited limited biodegradability. The extent of biogenic carbon conversion varied from 21 to 96% among papers, which contrasts with the uniform assumption of 50% by the Intergovernmental Panel on Climate Change (IPCC) for all degradable materials discarded in landfills. Biochemical methane potential tests also showed that the solids to liquid ratio used in the test can influence the results. Copyright © 2015 Elsevier B.V. All rights reserved.

A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol.

PubMed

Yuan, Zhaoyang; Wen, Yangbing; Kapu, Nuwan Sella; Beatson, Rodger; Mark Martinez, D

2017-01-01

Bamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel. An integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture liquor showed that an ethanol recovery of 0.46 g/g sugar was achieved with 93.2% of hydrolyzed sugars being consumed. A mass balance of the overall process showed that 76.59 g of solids was recovered from 100 g (o.d.) of green bamboo. The present work proposes an integrated biorefinery process that contains alkaline pre-extraction, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, thereby allowing the improvement and expansion of bamboo utilization in industrial processes.

Lightweight Thermal Protection System for Atmospheric Entry

NASA Technical Reports Server (NTRS)

Stewart, David; Leiser, Daniel

2007-01-01

TUFROC (Toughened Uni-piece Fibrous Reinforced Oxidation-resistant Composite) has been developed as a new thermal protection system (TPS) material for wing leading edge and nose cap applications. The composite withstands temperatures up to 1,970 K, and consists of a toughened, high-temperature surface cap and a low-thermal-conductivity base, and is applicable to both sharp and blunt leading edge vehicles. This extends the possible application of fibrous insulation to the wing leading edge and/or nose cap on a hypersonic vehicle. The lightweight system comprises a treated carbonaceous cap composed of ROCCI (Refractory Oxidation-resistant Ceramic Carbon Insulation), which provides dimensional stability to the outer mold line, while the fibrous base material provides maximum thermal insulation for the vehicle structure.

Improving the performance of enzymes in hydrolysis of high solids paper pulp derived from MSW.

PubMed

Puri, Dhivya J; Heaven, Sonia; Banks, Charles J

2013-01-01

The research aimed to improve the overall conversion efficiency of the CTec® family of enzymes by identifying factors that lead to inhibition and seeking methods to overcome these through process modification and manipulation. The starting material was pulp derived from municipal solid waste and processed in an industrial-scale washing plant. Analysis of the pulp by acid hydrolysis showed a ratio of 55 : 12 : 6 : 24 : 3 of glucan : xylan : araban/galactan/mannan : lignin : ash. At high total solids content (>18.5% TS) single-stage enzyme hydrolysis gave a maximum glucan conversion of 68%. It was found that two-stage hydrolysis could give higher conversion if sugar inhibition was removed by an intermediate fermentation step between hydrolysis stages. This, however, was not as effective as direct removal of the sugar products, including xylose, by washing of the residual pulp at pH 5. This improved the water availability and allowed reactivation of the pulp-bound enzymes. Inhibition of enzyme activity could further be alleviated by replenishment of β-glucosidase which was shown to be removed during the wash step. The two-stage hydrolysis process developed could give an overall glucan conversion of 88%, with an average glucose concentration close to 8% in 4 days, thus providing an ideal starting point for ethanol fermentation with a likely yield of 4 wt%. This is a significant improvement over a single-step process. This hydrolysis configuration also provides the potential to recover the sugars associated with residual solids which are diluted when washing hydrolysed pulp.

The material and biological characteristics of osteoinductive calcium phosphate ceramics

PubMed Central

Tang, Zhurong; Li, Xiangfeng; Tan, Yanfei

2018-01-01

Abstract The discovery of osteoinductivity of calcium phosphate (Ca-P) ceramics has set an enduring paradigm of conferring biological regenerative activity to materials with carefully designed structural characteristics. The unique phase composition and porous structural features of osteoinductive Ca-P ceramics allow it to interact with signaling molecules and extracellular matrices in the host system, creating a local environment conducive to new bone formation. Mounting evidence now indicate that the osteoinductive activity of Ca-P ceramics is linked to their physicochemical and three-dimensional structural properties. Inspired by this conceptual breakthrough, many laboratories have shown that other materials can be also enticed to join the rank of tissue-inducing biomaterials, and besides the bones, other tissues such as cartilage, nerves and blood vessels were also regenerated with the assistance of biomaterials. Here, we give a brief historical recount about the discovery of the osteoinductivity of Ca-P ceramics, summarize the underlying material factors and biological characteristics, and discuss the mechanism of osteoinduction concerning protein adsorption, and the interaction with different types of cells, and the involvement of the vascular and immune systems. PMID:29423267

[Ru(bipy)3]2+ nanoparticle-incorporate dental light cure resin to promote photobiomodulation therapy for enhanced vital pulp tissue repair

NASA Astrophysics Data System (ADS)

Mosca, Rodrigo C.; Young, Nicholas; Zeituni, Carlos A.; Arany, Praveen R.

2018-02-01

The use of nanoparticle on dental light cure resin is not new, currently several compounds (nanoadditives) are used to promote better communication between the restorative material and biological tissues. The interest for this application is growing up to enhance mechanical proprieties to dental tissue cells regeneration. Bioactive nanoparticles and complex compounds with multiple functions are the major target for optimizing the restorative materials. In this work, we incorporate [Ru(bipy)3]2+ nanoparticles, that absorbs energy at 450 nm (blue-light) and emits strongly at 620 nm (red-light), in PLGA Microspheres and insert it in Dental Light Cure Resin to promote the Photobiomodulation Therapy (PBM) effects to accelerate dental pulp repair by in vitro using cytotoxicity and proliferation assay.

Fiber resources

Treesearch

P. J. Ince

2004-01-01

In economics, primary inputs or factors of production define the term ‘resources.’ Resources include land resources (plants, animals, and minerals), labor, capital, and entrepreneurship. Almost all pulp and paper fiber resources are plant materials obtained from trees or agricultural crops. These resources encompass plant materials harvested directly from the land (...

10 CFR 1016.37 - Destruction of documents or material containing Restricted Data.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Data. 1016.37 Section 1016.37 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) SAFEGUARDING OF RESTRICTED DATA Control of Information § 1016.37 Destruction of documents or material containing Restricted Data. Documents containing Restricted Data may be destroyed by burning, pulping, or another method that...

10 CFR 1016.37 - Destruction of documents or material containing Restricted Data.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Data. 1016.37 Section 1016.37 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) SAFEGUARDING OF RESTRICTED DATA Control of Information § 1016.37 Destruction of documents or material containing Restricted Data. Documents containing Restricted Data may be destroyed by burning, pulping, or another method that...

Defective secretion of mucilage is the cellular basis for agravitropism in primary roots of Zea mays cv. Ageotropic

NASA Technical Reports Server (NTRS)

Miller, I.; Moore, R.

1990-01-01

Root caps of primary, secondary, and seminal roots of Z. mays cv. Kys secrete large amounts of mucilage and are in close contact with the root all along the root apex. These roots are strongly graviresponsive. Secondary and seminal roots of Z. mays cv. Ageotropic are also strongly graviresponsive. Similarly, their caps secrete mucilage and closely appress the root all along the root apex. However, primary roots of Z. mays cv. Ageotropic are non-responsive to gravity. Their caps secrete negligible amounts of mucilage and contact the root only at the extreme apex of the root along the calyptrogen. These roots become graviresponsive when their tips are coated with mucilage or mucilage-like materials. Peripheral cells of root caps of roots of Z. mays cv. Kys contain many dictyosomes associated with vesicles that migrate to and fuse with the plasmalemma. Root-cap cells of secondary and seminal (i.e. graviresponsive) roots of Z. mays cv. Ageotropic are similar to those of primary roots of Z. mays cv. Kys. However, root-cap cells of primary (i.e. non-graviresponsive) roots of Z. mays cv. Ageotropic have distended dictyosomal cisternae filled with an electron-dense, granular material. Large vesicles full of this material populate the cells and apparently do not fuse with the plasmalemma. Taken together, these results suggest that non-graviresponsiveness of primary roots of Z. mays cv. Ageotropic results from the lack of apoplastic continuity between the root and the periphery of the root cap. This is a result of negligible secretion of mucilage by cells along the edge of the root cap which, in turn, appears to be due to the malfunctioning of dictyosomes in these cells.

Paper pulp-based adsorbents for the removal of pharmaceuticals from wastewater: A novel approach towards diversification.

PubMed

Oliveira, Gonçalo; Calisto, Vânia; Santos, Sérgio M; Otero, Marta; Esteves, Valdemar I

2018-08-01

In this work, two pulps, bleached (BP) and raw pulp (RP), derived from the paper production process, were used as precursors of non-activated and activated carbons (ACs). In the case of non-ACs, the production involved either pyrolysis or pyrolysis followed by acid washing. For ACs production, the pulps were impregnated with K 2 CO 3 or H 3 PO 4 , and then pyrolysed and acid washed. After production, the materials were physically and chemically characterized. Then, batch adsorption tests on the removal of two pharmaceuticals (the anti-epileptic carbamazepine (CBZ) and the antibiotic sulfamethoxazole (SMX)) from ultra-pure water and from Waste Water Treatment Plant (WWTP) effluents were performed. In ultra-pure water, non-ACs were not able to adsorb CBZ or SMX while ACs showed good adsorption capacities. In WWTP effluents, although ACs satisfactorily adsorbed CBZ and SMX, they showed lower adsorption capacities for the latter. Tests with WWTP effluents revealed that the best adsorption capacities were achieved by carbons produced from BP and activated with H 3 PO 4 : 92±19mgg -1 for CBZ and 13.0±0.6mgg -1 for SMX. These results indicate the potential of paper pulps as precursors for ACs that can be applied in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Relationship Between the Remaining Dentin Thickness and Coronal Pulp Status of Decayed Primary Molars

PubMed Central

Berbari, Roula; Fayyad-Kazan, Hussein; Ezzedine, Mohamad; Fayyad-Kazan, Mohammad; Bandon, Daniel; Sfeir, Elia

2017-01-01

Aims and Objectives: The aim of this study was to assess the correlation between the remaining dentin thickness (RDT) in deep decayed primary molars and the inflammatory status and bacterial composition of the corresponding coronal pulp. We hypothesized that RDT could be used as a reference for clinicians in assigning the indication for pulpotomy. Materials and Methods: Pulpotomies were conducted on the cameral pulp of 48 primary molars. Microorganisms, such as Lactobacillus sp., Streptococcus sp., and Prevotella sp., were identified and quantified and levels of tumor necrosis factor-alpha (TNF-α) and interlukin-6 (IL-6) were assessed. The correlation between the pre-operative RDT based on radiographic images and inflammatory-microbial profiles in vitro was evaluated using Spearman's rho correlation coefficient. All data analysis was performed using a statistical software program (SPSS 20.0, SPSS Inc., Chicago, IL, USA). Results: Immunological and microbiological studies revealed elevated levels of TNF-α and IL-6 cytokines, and Lactobacillus sp., Streptococcus sp. and Prevotella sp. in the cameral pulp with an RDT measuring up to 1.1 mm. No significant relationship could be established between RDT, inflammatory status and microbial content of the pulps. Conclusion: The RDT remains a key clinical factor that needs to be assessed when establishing the indication for pulpotomy. Additional parameters that can improve this therapy should be investigated in the future. PMID:29026700

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

PubMed Central

SIPERT, Carla Renata; MORANDINI, Ana Carolina de Faria; MODENA, Karin Cristina da Silva; DIONÍSIO, Thiago José; MACHADO, Maria Aparecida Andrade Moreira; de OLIVEIRA, Sandra Helena Penha; CAMPANELLI, Ana Paula; SANTOS, Carlos Ferreira

2013-01-01

Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 - 10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation. PMID:23739851

27 CFR 24.243 - Filtering aids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... fibers, pulps, earths, or similar materials, may be used as filtering aids in the cellar treatment and finishing of wine. Agar-agar, carrageenan, cellulose, and diatomaceous earth are commonly employed inert...

27 CFR 24.243 - Filtering aids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... fibers, pulps, earths, or similar materials, may be used as filtering aids in the cellar treatment and finishing of wine. Agar-agar, carrageenan, cellulose, and diatomaceous earth are commonly employed inert...

Laccase-mediated synthesis of lignin-core hyperbranched copolymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannatelli, Mark D.; Ragauskas, Arthur J.

Lignin, one of the major chemical constituents of woody biomass, is the second most abundant biopolymer found in nature. The pulp and paper industry has long produced lignin on the scale of millions of tons annually as a by-product of the pulping process, and the dawn of cellulosic ethanol production has further contributed to this amount. Historically, lignin has been perceived as a waste material and burned as a fuel for the pulping process. But, recent research has been geared toward developing cost-effective technologies to convert lignin into valuable commodities. Attributing to the polyphenolic structure of lignin, enzymatic modification ofmore » its surface using laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) has demonstrated to be highly successful. The current study aims at developing lignin-core hyperbranched copolymers via the laccase-assisted copolymerization of kraft lignin with methylhydroquinone and a trithiol. Based on the physical properties of the resulting material, it is likely that crosslinking reactions have taken place during the drying process to produce a copolymeric network rather than discrete hyperbranched copolymers, with NMR data providing evidence of covalent bonding between monomers. A preliminary thermal analysis data reveals that the copolymeric material possesses a moderate glass transition temperature and exhibits good thermostability, thus may have potential application as a lignin-based thermoplastic. Scanning electron microscopy images confirm the smooth, glossy surface of the material and that it is densely packed. Our results are a sustainable, ecofriendly, economic method to create an exciting novel biomaterial from a renewable feedstock while further enhancing lignin valorization.« less

Laccase-mediated synthesis of lignin-core hyperbranched copolymers

DOE PAGES

Cannatelli, Mark D.; Ragauskas, Arthur J.

2017-06-06

Lignin, one of the major chemical constituents of woody biomass, is the second most abundant biopolymer found in nature. The pulp and paper industry has long produced lignin on the scale of millions of tons annually as a by-product of the pulping process, and the dawn of cellulosic ethanol production has further contributed to this amount. Historically, lignin has been perceived as a waste material and burned as a fuel for the pulping process. But, recent research has been geared toward developing cost-effective technologies to convert lignin into valuable commodities. Attributing to the polyphenolic structure of lignin, enzymatic modification ofmore » its surface using laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) has demonstrated to be highly successful. The current study aims at developing lignin-core hyperbranched copolymers via the laccase-assisted copolymerization of kraft lignin with methylhydroquinone and a trithiol. Based on the physical properties of the resulting material, it is likely that crosslinking reactions have taken place during the drying process to produce a copolymeric network rather than discrete hyperbranched copolymers, with NMR data providing evidence of covalent bonding between monomers. A preliminary thermal analysis data reveals that the copolymeric material possesses a moderate glass transition temperature and exhibits good thermostability, thus may have potential application as a lignin-based thermoplastic. Scanning electron microscopy images confirm the smooth, glossy surface of the material and that it is densely packed. Our results are a sustainable, ecofriendly, economic method to create an exciting novel biomaterial from a renewable feedstock while further enhancing lignin valorization.« less

Laccase-mediated synthesis of lignin-core hyperbranched copolymers.

PubMed

Cannatelli, Mark D; Ragauskas, Arthur J

2017-08-01

Lignin, one of the major chemical constituents of woody biomass, is the second most abundant biopolymer found in nature. The pulp and paper industry has long produced lignin on the scale of millions of tons annually as a by-product of the pulping process, and the dawn of cellulosic ethanol production has further contributed to this amount. Historically, lignin has been perceived as a waste material and burned as a fuel for the pulping process. However, recent research has been geared toward developing cost-effective technologies to convert lignin into valuable commodities. Attributing to the polyphenolic structure of lignin, enzymatic modification of its surface using laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) has demonstrated to be highly successful. The current study aims at developing lignin-core hyperbranched copolymers via the laccase-assisted copolymerization of kraft lignin with methylhydroquinone and a trithiol. Based on the physical properties of the resulting material, it is likely that crosslinking reactions have taken place during the drying process to produce a copolymeric network rather than discrete hyperbranched copolymers, with NMR data providing evidence of covalent bonding between monomers. Preliminary thermal analysis data reveals that the copolymeric material possesses a moderate glass transition temperature and exhibits good thermostability, thus may have potential application as a lignin-based thermoplastic. Scanning electron microscopy images confirm the smooth, glossy surface of the material and that it is densely packed. The presented results are a sustainable, ecofriendly, economic method to create an exciting novel biomaterial from a renewable feedstock while further enhancing lignin valorization.

The Use of Esterified Lignin for Synthesis of Durable Composites

Treesearch

S. Olsson; E. Ostmark; R.E. Ibach; C.M. Clemons; K.B. Segerholm; F. Englund

2011-01-01

Lignin is a natural polymer and one of the most abundant materials on earth. Despite this fact, lignin is often viewed as a by-product in chemical pulp processing and the use of lignin as a sustainable material is low. However, research and public awareness of sustainability have opened up new possibilities for using lignin as a material.

Evaluation of in situ layers for treatment of acid mine drainage: a field comparison.

PubMed

Hulshof, Andrea H M; Blowes, David W; Gould, W Douglas

2006-05-01

Reactive treatment layers, containing labile organic carbon, were evaluated to determine their ability to promote sulfate reduction and metal sulfide precipitation within a tailings impoundment, thereby treating tailings effluent prior to discharge. Organic carbon materials, including woodchips and pulp waste, were mixed with the upper meter of tailings in two separate test cells, a third control cell contained only tailings. In the woodchip cell sulfate reduction rates were 500 mg L-1a-1, (5.2 mmol L-1a-1) this was coupled with the gradual removal of 350 mg L-1 Zn (5.4 mmol L-1). Decreased delta13CDIC values from -3 per thousand to as low as -12 per thousand indicated that sulfate reduction was coupled with organic carbon oxidation. In the pulp waste cell the most dramatic change was observed near the interface between the pulp waste amended tailings and the underlying undisturbed tailings. Sulfate reduction rates were 5000 mg L-1a-1 (52 mmol L-1a-1), Fe concentrations decreased by 80-99.5% (148 mmol L-1) and Zn was consistently <5 mg L-1. Rates of sulfate reduction and metal removal decreased as the pore water migrated upward into the shallower tailings. Increased rates of sulfate reduction in the pulp waste cell were consistent with decreased delta13CDIC values, to as low as -22 per thousand, and increased populations of sulfate reducing bacteria. Lower concentrations of the nutrients, phosphorus, organic carbon and nitrogen in the woodchip material contribute to the lower sulfate reduction rates observed in the woodchip cell.

MASSAHAKE whole tree harvesting method for pulp raw-material and fuel -- R&D in 1993--1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asplund, D.A.; Ahonen, M.A.

1993-12-31

In Finland biofuels and hydropower are the only indigenous fuels available. Peat, wood and wood derived fuels form about 18% of total primary energy requirement. The largest wood and wood fuel user in Finland is wood processing industry, paper, pulp, sawmills. Due to silvicultural activities the growth of forests has developed an instant need for first thinnings. This need is about 12% of total stem wood growth. With conventional harvesting methods this would produce about 8 mill. m{sup 3} pulp raw material and 2 mill. m{sup 3} wood fuel. By using integrated harvesting methods about 12 mill. m{sup 3} pulpmore » raw material and 8 mill. m{sup 3} (about 1, 3 mill. toe) fuel could be produced. At the moment, there is no economically profitable method for harvesting first thinning trees for industrial use or energy production. Hence, there are a few ongoing research projects aiming at solving the question of integrated harvesting. MASSAHAKE chip purification method has been under R&D since 1987. Research with continuous experimental line (capacity 5--10 loose-m{sup 3}) has been done in 1991 and 1992. The research has concentrated on pine whole tree chip treatment, but preliminary tests with birch whole tree chips has been done. The experiment line will be modified for birth whole tree chips during 1993. Based on the research results more than 60% of the whole tree chips can be separated to pulp raw material with < 1% bark content. This amount is 1.5--2 times more than with present technology. The yield of fuel fraction is 2--4 times higher compared to present methods. Fuel fraction is homogeneous and could be used in most furnaces for energy production. By replacing fossil fuels with wood fuel in energy production it is possible to reduce CO{sub 2}-emissions significantly. This paper presents the wood fuel research areas in Finland and technical potential of MASSAHAKE-method including the plant for building a demonstration plant based on this technology.« less

Hybrid calcium phosphate coatings for implants

NASA Astrophysics Data System (ADS)

Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

2016-08-01

Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

Materials for the pulp and paper industry. Section 1: Development of materials for black liquor recovery boilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keiser, J.R.; Hubbard, C.R.; Payzant, E.A.

1997-04-01

Black liquor recovery boilers are essential components of kraft pulp and paper mills because they are a critical element of the system used to recover the pulping chemicals required in the kraft pulping process. In addition, the steam produced in these boilers is used to generate a significant portion of the electrical power used in the mill. Recovery boilers require the largest capital investment of any individual component of a paper mill, and these boilers are a major source of material problems in a mill. The walls and floors of these boilers are constructed of tube panels that circulate highmore » pressure water. Molten salts (smelt) accumulate on the floor of recovery boilers, and leakage of water into the boiler can result in a violent explosion when the leaked water instantly vaporizes upon contacting the molten smelt. Because corrosion of the conventionally-used carbon steel tubing was found to be excessive in the lower section of recovery boilers, use of stainless steel/carbon steel co-extruded tubing was adopted for boiler walls to lessen corrosion and reduce the likelihood of smelt/water explosions. Eventually, this co-extruded or composite (as it is known in the industry) tubing was selected for use as a portion or all of the floor of recovery boilers, particularly those operating at pressures > 6.2 MPa (900 psi), because of the corrosion problems encountered in carbon steel floor tubes. Since neither the cause of the cracking nor an effective solution has been identified, this program was established to develop a thorough understanding of the degradation that occurs in the composite tubing used for walls and floors. This is being accomplished through a program that includes collection and review of technical reports, examination of unexposed and cracked tubes from boiler floors, computer modeling to predict residual stresses under operating conditions, and operation of laboratory tests to study corrosion, stress corrosion cracking, and thermal fatigue.« less

NDE Process Development Specification for SRB Composite Nose Cap

NASA Technical Reports Server (NTRS)

Suits, M.

1999-01-01

The Shuttle Upgrade program is a continuing improvement process to enable the Space Shuttle to be an effective space transportation vehicle for the next few decades. The Solid Rocket Booster (SRB), as a component of that system, is currently undergoing such an improvement. Advanced materials, such as composites, have given us a chance to improve performance and to reduce weight. The SRB Composite Nose Cap (CNC) program aims to replace the current aluminum nose cap, which is coated with a Thermal Protection System and poses a possible debris hazard, with a lighter, stronger, CNC. For the next 2 years, this program will evaluate the design, material selection, properties, and verification of the CNC. This particular process specification cites the methods and techniques for verifying the integrity of such a nose cap with nondestructive evaluation.

Development of cleaved amplified polymorphic sequence markers and a CAPS-based genetic linkage map in watermelon (Citrullus lanatus [Thunb.] Matsum. and Nakai) constructed using whole-genome re-sequencing data

PubMed Central

Liu, Shi; Gao, Peng; Zhu, Qianglong; Luan, Feishi; Davis, Angela R.; Wang, Xiaolu

2016-01-01

Cleaved amplified polymorphic sequence (CAPS) markers are useful tools for detecting single nucleotide polymorphisms (SNPs). This study detected and converted SNP sites into CAPS markers based on high-throughput re-sequencing data in watermelon, for linkage map construction and quantitative trait locus (QTL) analysis. Two inbred lines, Cream of Saskatchewan (COS) and LSW-177 had been re-sequenced and analyzed by Perl self-compiled script for CAPS marker development. 88.7% and 78.5% of the assembled sequences of the two parental materials could map to the reference watermelon genome, respectively. Comparative assembled genome data analysis provided 225,693 and 19,268 SNPs and indels between the two materials. 532 pairs of CAPS markers were designed with 16 restriction enzymes, among which 271 pairs of primers gave distinct bands of the expected length and polymorphic bands, via PCR and enzyme digestion, with a polymorphic rate of 50.94%. Using the new CAPS markers, an initial CAPS-based genetic linkage map was constructed with the F2 population, spanning 1836.51 cM with 11 linkage groups and 301 markers. 12 QTLs were detected related to fruit flesh color, length, width, shape index, and brix content. These newly CAPS markers will be a valuable resource for breeding programs and genetic studies of watermelon. PMID:27162496

Banana (Musa spp) from peel to pulp: ethnopharmacology, source of bioactive compounds and its relevance for human health.

PubMed

Pereira, Aline; Maraschin, Marcelo

2015-02-03

Banana is a fruit with nutritional properties and also with acclaimed therapeutic uses, cultivated widely throughout the tropics as source of food and income for people. Banana peel is known by its local and traditional use to promote wound healing mainly from burns and to help overcome or prevent a substantial number of illnesses, as depression. This review critically assessed the phytochemical properties and biological activities of Musa spp fruit pulp and peel. A survey on the literature on banana (Musa spp, Musaceae) covering its botanical classification and nomenclature, as well as the local and traditional use of its pulp and peel was performed. Besides, the current state of art on banana fruit pulp and peel as interesting complex matrices sources of high-value compounds from secondary metabolism was also approached. Dessert bananas and plantains are systematic classified into four sections, Eumusa, Rhodochlamys, Australimusa, and Callimusa, according to the number of chromosomes. The fruits differ only in their ploidy arrangement and a single scientific name can be given to all the edible bananas, i.e., Musa spp. The chemical composition of banana's peel and pulp comprise mostly carotenoids, phenolic compounds, and biogenic amines. The biological potential of those biomasses is directly related to their chemical composition, particularly as pro-vitamin A supplementation, as potential antioxidants attributed to their phenolic constituents, as well as in the treatment of Parkinson's disease considering their contents in l-dopa and dopamine. Banana's pulp and peel can be used as natural sources of antioxidants and pro-vitamin A due to their contents in carotenoids, phenolics, and amine compounds, for instance. For the development of a phytomedicine or even an allopathic medicine, e.g., banana fruit pulp and peel could be of interest as raw materials riches in beneficial bioactive compounds. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Controlling the release of wood extractives into water bodies by selecting suitable eucalyptus species

NASA Astrophysics Data System (ADS)

Kilulya, K. F.; Msagati, T. A. M.; Mamba, B. B.; Ngila, J. C.; Bush, T.

Pulping industries are increasing worldwide as a result of the increase in the demand for pulp for cellulose derivatives and paper manufacturing. Due to the activities involved in pulping processes, different chemicals from raw materials (wood) and bleaching agents are released in pulp-mill effluent streams discharged into the environment and find their way into water bodies. Large quantities of water and chemicals used in pulping result in large amounts of wastewater with high concentrations of extractives such as unsaturated fatty acids, which are known to be toxic, and plant sterols which affect the development, growth and reproduction of aquatic organisms. This study was aimed at assessing the composition of extractives in two eucalyptus species used for pulp production in South Africa, in order to identify the suitable species with regard to extractive content. Samples from two eucalyptus plant species (Eucalyptus grandis and Eucalyptus dunnii) were collected from three sites and analysed for extractives by first extracting with water, followed by Soxhlet extraction using acetone. Compounds were identified and quantified using gas chromatography-mass spectrometry (GC-MS). Major classes of extractives identified were fatty acids (mainly hexadecanoic acid, 9,12-octadecadienoic, 9-octadecenoic and octadecanoic acids) and sterols (mainly β-sitosterol and stigmastanol). E. dunnii was found to contain higher amounts of the compounds compared to those found in E. grandis in all sampled sites. Principal component analysis (PCA) was performed and explained 92.9% of the total variation using three principal components. It was revealed that the percentage of fatty acids, which has a negative influence on both principal components 2 and 3, was responsible for the difference between the species. E. grandis, which was found to contain low amounts of extractives, was therefore found suitable for pulping with regard to minimal water usage and environment pollution.

Preservice elementary teachers learning to use curriculum materials to plan and teach science

NASA Astrophysics Data System (ADS)

Gunckel, Kristin Lee

New elementary teachers rely heavily on curriculum materials, but available science curriculum materials do not often support teachers in meeting specified learning goals, engaging students in the inquiry and application practices of science, or leveraging students' intellectual and cultural resources for learning. One approach to supporting new elementary teachers in using available science curriculum materials is to provide frameworks to scaffold preservice teachers' developing lesson planning and teaching practices. The Inquiry-Application Instructional Model (I-AIM) and the Critical Analysis and Planning (CA&P) tool were designed to scaffold preservice teachers' developing practice to use curriculum materials effectively to plan and teach science. The I-AIM identifies functions for each activity in an instructional sequence. The CA&P provides guides preservice teachers in modifying curriculum materials to better fit I-AIM and leverage students' resources for learning. This study followed three elementary preservice teachers in an intern-level science method course as they learned to use the I-AIM and CA&P to plan and teach a science unit in their field placement classrooms. Using a sociocultural perspective, this study focused on the ways that the interns used the tools and the mediators that influenced how they used the tools. A color-coding analysis procedure was developed to identify the teaching patterns in the interns' planned instructional approaches and enacted activity sequences and compare those to the patterns implied by the I-AIM and CA&P tools. Interviews with the interns were also conducted and analyzed, along with the assignments they completed for their science methods course, to gain insight into the meanings the interns made of the tools and their experiences planning and teaching science. The results show that all three interns had some successes using the I-AIM and CA&P to analyze their curriculum materials and to plan and teach science lessons. However, all three interns used the tools in different ways, and some of their ways of using the tools were different from the intentions for the tools. These differences can be accounted for by the variety of mediators that influenced the interns' use of the I-AIM and CA&P tools. These mediators were rooted in the Discourses at play in the various communities in which the interns participated during their teacher preparation program. Some of the practices and resources of these various Discourses interfered with or supported the interns' use of the I-AIM and CA&P tools. Each intern took a different trajectory through these Discourses and encountered different practices that mediated how each used the I-AIM and CA&P tools. The results of this study suggest that the goal of preparing preservice teachers to use the I-AIM and CA&P tools should be to provide preservice teachers with opportunities to use the tools and help them develop the metaknowledge about the tools necessary to critically analyze the affordances and weaknesses of different approaches to teaching science.

[Bioactive glass 45S5-silk fibroin membrane supports proliferation and differentiation of human dental pulp stem cells].

PubMed

Lyu, Xiaoshuai; Li, Zhengmao; Wang, Haiyan; Yang, Xuechao

2015-12-01

To investigate the effect of bioactivity glass 45S5- silk fibroin(BG45S5- SF) membrane on growth, proliferation and differentiation of human dental pulp stem cells(hDPSC), and to provide new ideas and method for the regeneration of pulp-dentine complex. hDPSC seed on pure silk fibroin membrane (protein membrane group) and BG45S5-SF membrane with different concentrations(1 000, 5 000 mg/L, composite membrane group A and B, respectively) were prepared, and the materials were incubated in cell culture fluid for 24 h. No material membrane orifice plate was used as blank control group. Contact angle meter was used to measure surface contact angle of protein membrane and composite membrane group(each group had three repeated holes). Cell proliferation was assessed by cell counting kit- 8 on the 4, 7, 14, and 21 days. The state of adhesion and growth of hDPSC on the materials surface was evaluated by scanning electron microscopy and cytoskeleton staining; and alkaline phosphatase (ALP) activity was measured to evaluate the cell differentiation potential. The expression of odontoblastic differentiation-related genes was measured by real-time PCR. Surface contact angle of the protein membrane group and composite membrane group A and group B were 89.51° ± 0.12°, 70.32° ± 0.07° and 71.31° ± 0.09° respectively. hDPSC adhered well on each materials surface on the 7, 14, 21 days, ALP activity and differentiation genes of composite membrane group A and B rised more significantly than the blank control group and protein membrane group did (P<0.05). Dentin matrix protein1(DMP- 1), dentin sialoprotein(DSP), ALP, osteocalcin(OC) mRNA expression reached peak on the 14 days in group A, and in group B on the 21 days. Bone sialoprotein(BSP) mRNA expression in both group A and B reached peak on the 21 days. BG45S5- SF membrane is able to support the proliferation and showed the potential of odontoblastic differentiation for hDPSC. This finding suggests that BG45S5-SF membrane was a kind of tissue engineering film material with the regeneration potential for pulp-dentine complex.

Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

PubMed Central

Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

2016-01-01

Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

Thermomechanical pulping of loblolly pine juvenile wood

Treesearch

Gary C. Myers

2002-01-01

Intensive forest management, with a heavy emphasis on ecosystem management and restoring or maintaining forest health, will result in the removal of smaller diameter materials from the forest. This increases the probability of higher juvenile wood content in the harvested materials. The purpose of this study was to compare the performance of loblolly pine juvenile and...

Cellulosic ethanol byproducts as a bulking agent

Treesearch

J.M. Considine; D. Coffin; J.Y. Zhu; D.H. Mann; X. Tang

2017-01-01

Financial enhancement of biomass value prior to pulping requires subsequent use of remaining materials; e.g., high value use of remaining stock material after cellulosic ethanol production would improve the economics for cellulosic ethanol. In this work, use of enzymatic hydrolysis residual solids (EHRS), a cellulosic ethanol byproduct, were investigated as a bulking...

Guidance for Subaqueous Dredged Material Capping.

DTIC Science & Technology

1998-06-01

from Ambrose Channel , over the contaminated sediments. At least two intermediate sur- veys and additional capping were required before capping was...organisms to a given bioturbation depth; reducing contami- nant flux rates to achieve specific sediment, pore water, or water column target...bathymetry, bottom slopes, cur- rents, water depths, water column density stratification, erosion/accretion trends, proximity to navigation channels

78 FR 75420 - Self-Regulatory Organizations; BOX Options Exchange LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-11

... To Amend Interpretive Material To Rule 5050 To Eliminate the Cap on the Number of Additional Series... Rule 5050 (Series of Options Contracts Open for Trading) to eliminate the cap on the number of... Rule 5050 (Series of Options Contracts Open for Trading) to eliminate the cap on the number of...

NMR Guided Design of Endcaps With Improved Oxidation Resistance

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B.; Frimer, Aryeh A.

2002-01-01

A polyimide is a polymer composed of alternating units of diamine and dianhydride, linked to each other via an imide bond. PMR polyimides, commonly used in the aerospace industry, are generally capped at each end by a norbornene endcap which serves a double function: (1) It limits the number of repeating units and, hence, the average molecular weight of the various polymer chains (oligomers), thereby improving processibility; (2) Upon further treatment (curing), the endcap crosslinks the various oligomer strands into a tough heat-resistant piece. Norbornenyl-end capped PMR polyimide resins' are widely used as polymer matrix composite materials for aircraft engine applications,2 since they combine ease of processing with good oxidative stability up to 300 C. PMR resins are prepared by a twestep approach involving the initial formation of oligomeric pre-polymers capped at both ends by a latent reactive end cap. The end cap undergoes cross-linking during higher temperature processing, producing the desired low density, high specific strength materials, as shown for PMR-15.

In-vitro transdentinal diffusion of monomers from adhesives.

PubMed

Putzeys, Eveline; Duca, Radu Corneliu; Coppens, Lieve; Vanoirbeek, Jeroen; Godderis, Lode; Van Meerbeek, Bart; Van Landuyt, Kirsten L

2018-06-01

Biocompatibility of adhesives is important since adhesives may be applied on dentin near the pulp. Accurate knowledge of the quantity of monomers reaching the pulp is important to determine potential side effects. The aim of this study was to assess the transdentinal diffusion of residual monomers from dental adhesive systems using an in-vitro pulp chamber model. Dentin disks with a thickness of 300 µm were produced from human third molars. These disks were fixed between two open-ended glass tubes, representing an in-vitro pulp chamber. The etch-and-rinse adhesive OptiBond FL and the self-etch adhesive Clearfil SE Bond were applied to the dentin side of the disks, while on in the pulpal side, the glass tube was filled with 600 µL water. The transdentinal diffusion of different monomers was quantified using ultra-performance liquid chromatography-tandem mass spectrometry. The monomers HEMA, CQ, BisGMA, GPDM, 10-MDP and UDMA eluted from the dental materials and were able to diffuse through the dentin disks to a certain extent. Compounds with a lower molecular weight (uncured group: HEMA 7850 nmol and CQ 78.2 nmol) were more likely to elute and diffuse compared to monomers with a higher molecular weight (uncured group: BisGMA 0.42 nmol). When the adhesives were left uncured, diffusion was up to 10 times higher compared to the cured conditions. This in-vitro research resulted in the quantification of various monomers able to diffuse through dentin and therefore contributes to a more detailed understanding about the potential exposure of the dental pulp to monomers from dental adhesives. Biocompatibility of adhesives is important since adhesives may be applied on dentin near the pulp, where tubular density and diameter are greatest. Copyright © 2018. Published by Elsevier Ltd.

Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique.

PubMed

Camargo, Samira Esteves Afonso; Valera, Marcia Carneiro; Camargo, Carlos Henrique Ribeiro; Gasparoto Mancini, Maria Nadir; Menezes, Marcia Maciel

2007-09-01

This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 microg) and human (2.27 +/- 0.41 microg) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth.

Comparative evaluation of human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite: An in vitro study

PubMed Central

Taneja, Sonali; Mishra, Neha; Malik, Shubhra

2014-01-01

Introduction: Irrigation plays an indispensable role in removal of tissue remnants and debris from the complicated root canal system. This study compared the human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite. Materials and Methods: Pulp tissue was standardized to a weight of 9 mg for each sample. In all,60 samples obtained were divided into 6 groups according to the irrigating solution used- 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl, 5% calcium hypochlorite (Ca(OCl)2), 10% Ca(OCl)2, 5%chlorine dioxide (ClO2) and 13% ClO2. Pulp tissue was placed in each test tube carrying irrigants of measured volume (5ml) according to their specified subgroup time interval: 30 minutes (Subgroup A) and 60 minutes (Subgroup B). The solution from each sample test tube was filtered and was left for drying overnight. The residual weight was calculated by filtration method. Results: Mean tissue dissolution increases with increase in time period. Results showed 5.25% NaOCl to be most effective at both time intervals followed by 2.5% NaOCl at 60 minutes, 10%Ca(OCl)2 and 13% ClO2 at 60 minutes. Least amount of tissue dissolving ability was demonstrated by 5% Ca(OCl)2 and 5% ClO2 at 30 minutes. Distilled water showed no pulp tissue dissolution. Conclusion: Withinthe limitations of the study, NaOCl most efficiently dissolved the pulp tissue at both concentrations and at both time intervals. Mean tissue dissolution by Ca(OCl)2 and ClO2 gradually increased with time and with their increase in concentration. PMID:25506141

Review on Bamboo Utilization as Biocomposites, Pulp and Bioenergy

NASA Astrophysics Data System (ADS)

Yusuf, Sulaeman; Syamani, F. A.; Fatriasari, W.; Subyakto

2018-03-01

One of potential non wood bioresources utilized in industrial application is bamboos. Bamboos are include in graminae family which have high biomass productivity, easy and rapid production, wide avability and high holocellulose content. Indonesia has a huge potential of bamboos, more than 162 bamboo species are found however only some of them are planted that have a high economic value. Bamboos have some advantages such as can be harvested at 3 years, straight culm, high strength, easy to be processed, and relatively cheap. Research Center for Biomaterials has developed utilization of bamboo culm for ply bamboo product as alternative of plywood since 1995, using gombong bamboo, tali bamboo, sembilang bamboo, andong bamboo with PF resin as adhesive. Other biocomposite products from bamboos include particle board, cement board and polymer-bamboo fiber composites. In term of processing technique and final product quality, bamboo composites from ply bamboo are the most prospectable material to be utilized in industrial application. Yellow bamboo and betung bamboo have also been developed as pulp and paper. Biopulping using soda and kraft pulping after biological pretreatment using white rot fungi to remove lignin was used as pulping method in this conversion. Biokraft pulping with Trametes versicolor for 45 days with inoculum loading of 10% resulted better pulp quality compared to the other fungi. Betung bamboo had good morphological characteristics and chemical component content to be converted into bioenergy such as bioethanol. Several pretreatment methods have been developed in order to result high sugar yield. Microwave assisted acid hydrolysis was preferedin producing higher yield from the pretreated bamboo compared to enzymatic hydrolysis. By using this method, the bamboo pretreated by biological-microwave pretreatment results higher improvement to increase sugar yield.

The effect of oxyalkylation and application of polymer dispersions on the thermoformability and extensibility of paper.

PubMed

Kouko, Jarmo; Setälä, Harri; Tanaka, Atsushi; Khakalo, Alexey; Ropponen, Jarmo; Retulainen, Elias

2018-04-15

Wood fiber-based packaging materials, as renewable materials, have growing market potential due to their sustainability. A new breakthrough in cellulose-based packaging requires some improvement in the mechanical properties of paper. Bleached softwood kraft pulp was mechanically treated, in two stages, using high- and low-consistency refining, sequentially. Chemical treatment of pulp using the oxyalkylation method was applied to modify a portion of fiber material, especially the fiber surface, and its compatibility with polymer dispersions including one carbohydrate polymer. The results showed that the compatibility of the cellulosic fibers with some polymers could be improved with oxyalkylation. By adjusting mechanical and chemical treatments, and the thermoforming conditions, the formability of paper was improved, but simultaneously the strength and stiffness decreased. The results suggest that the formability of the paper is not a direct function of the extensibility of the applied polymer, but also depends on the fiber network structure and surface energy. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Pulpwood production in the Northeast 1968

Treesearch

James T. Bones; Neal P. Kingsley

1969-01-01

This report is based on a canvass of all pulpmills in the Northeast that use wood-either round wood or chips-as a basic raw material for a variety of products. Mills that use woodpulp as a raw material for insulation board and hardboard were also included in the canvass. However, the canvass did not include mills that use waste paper, rags, or pulping material other...

Strategies for decolorization and detoxification of pulp and paper mill effluent.

PubMed

Garg, Satyendra K; Tripathi, Manikant

2011-01-01

The potential hazards associated with industrial effluents, coupled with increasing awareness of environment problems, have prompted many countries to limit the indiscriminate discharge of untreated wastewaters. The pulp and paper industry has been among the most significant of industrial polluters of the waterways, and therefore has been one of the industries of concern. The pulp and paper industry produces large quantities of brown/black effluent that primarily result from pulping, bleaching, and paper-making production stages. The dark color and toxicity of pulp-paper mill effluent comes primarily from lignin and its chlorinated derivatives (e.g., lignosulphonic acid, resins, phenols, and hydrocarbons) that are released during various processing steps of lignocellulosic materials. The color originates from pulping and pulp bleaching stages, while adsorbable organic halides (AOX) originates exclusively from chlorine bleaching. Discharge of untreated effluent results in increased BOD/COD, slime growth, thermal problems, scum formation, discoloration, loss of aesthetic quality and toxicity to the aquatic life, in the receiving waterbodies. The dark brow color of pulp-paper effluent is not only responsible for aesthetic unacceptability, but also prevents the passage of sunlight through colored waterbodies. This reduces the photosynthetic activity of aquatic flora, ultimately causing depletion of dissolved oxygen. The pulp-paper organic waste, coupled with the presence of chlorine, results in the generation of highly chlorinated organic compounds. These toxic constituents of wastewater pose a human health risk through long term exposure. via drinking water and\\or through consumption of fish that can bioaccumulate certain pollutants from the food chain. Therefore, considerable attention has been focused by many countries on decolorization of paper mill effluents , along with reduction in the contaminants that pose human health or other environmental hazards. Various physicochemical remediation treatments in the pulp-paper industry are now used, or have been suggested, but often are not implemented, because of the high cost involved. More recently, the paper and pulp industry has been investigating the use of biological remediation steps to replace or augment current treatment strategies. Certain biological treatments offer opportunities to reduce cost (both capital and operating), reduce energy consumption, and minimize environmental impact. Two primary approaches may be effective to curtail release of toxic effluents: first, development of pulping and bleaching processes that emphasize improved oxygen delignification or biopulping, plus partial or complete replacement of chlorine treatment with hydrogen peroxide or with biobleaching; second, implementation of biological processing that involves sequential two-step anaerobic-aerobic or three-step aerobic-anaerobic treatment technologies at end of pipe. The selection of the specific process will depend upon the type of pollutants/toxicants/mutagens present in the effluent. The use of environmental-friendly technologies in the pulp and paper industry is becoming more popular, partly because of increasing regulation, and partly because of the availability of new techniques that can be used to economically deal with pollutants in the effluents. Moreover, biotechnology research methods are offering promise for even greater improvements in the future. The obvious ultimate goal of the industry and the regulators should be zero emission through recycling of industrial wastewater, or discharge of the bare minimum amount of toxicants or color.

Abrasion resistant track shoe grouser

DOEpatents

Fischer, Keith D; Diekevers, Mark S; Afdahl, Curt D; Steiner, Kevin L; Barnes, Christopher A

2013-04-23

A track shoe for a track-type vehicle. The track shoe includes a base plate and a grouser projecting away from the base plate. A capping surface structure of substantially horseshoe shaped cross-section is disposed across a distal portion of the grouser. The capping surface structure covers portions of a distal edge surface and adjacent lateral surfaces. The capping surface structure is formed from an material characterized by enhanced wear resistance relative to portions of the grouser underlying the capping surface structure.

Influence of kraft pulping on carboxylate content of softwood kraft pulps

Treesearch

Zheng Dang; Thomas Elder; Arthur J. Ragauskas

2006-01-01

This study characterizes changes in fiber charge, which is the carboxylate content of fibers, for two sets of kraft pulps: (1) conventional laboratory cooked loblolly pine kraft pulps and (2) conventional pulping (CK) versus low solids pulping (LS) pulps. Laboratory kraft pulping of loblolly pine was carried out to study the influence of pulping conditions, including...

A novel three-dimensional scaffold for regenerative endodontics: materials and biological characterizations.

PubMed

Bottino, Marco C; Yassen, Ghaeth H; Platt, Jeffrey A; Labban, Nawaf; Windsor, L Jack; Spolnik, Kenneth J; Bressiani, Ana H A

2015-11-01

An electrospun nanocomposite fibrous material holds promise as a scaffold, as well as a drug-delivery device to aid in root maturogenesis and the regeneration of the pulp-dentine complex. A novel three-dimensional (3D) nanocomposite scaffold composed of polydioxanone (PDS II®) and halloysite nanotubes (HNTs) was designed and fabricated by electrospinning. Morphology, structure, mechanical properties and cell compatibility studies were carried out to evaluate the effects of HNTs incorporation (0.5-10 wt% relative to PDS w/w). Overall, a 3D porous network was seen in the different fabricated electrospun scaffolds, regardless of the HNT content. The incorporation of HNTs at 10 wt% led to a significant (p < 0.0001) fibre diameter increase and a reduction in scaffold strength. Moreover, PDS-HNTs scaffolds supported the attachment and proliferation of human-derived pulp fibroblast cells. Quantitative proliferation assay performed with human dental pulp-derived cells as a function of nanotubes concentration indicated that the HNTs exhibit a high level of biocompatibility, rendering them good candidates for the potential encapsulation of distinct bioactive molecules. Collectively, the reported data support the conclusion that PDS-HNTs nanocomposite fibrous structures hold potential in the development of a bioactive scaffold for regenerative endodontics. Copyright © 2013 John Wiley & Sons, Ltd.

Construction materials as a waste management solution for cellulose sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Modolo, R., E-mail: regina.modolo@ua.pt; Ferreira, V.M.; Machado, L.M.

2011-02-15

Sustainable waste management system for effluents treatment sludge has been a pressing issue for pulp and paper sector. Recycling is always recommended in terms of environmental sustainability. Following an approach of waste valorisation, this work aims to demonstrate the technical viability of producing fiber-cement roof sheets incorporating cellulose primary sludge generated on paper and pulp mills. From the results obtained with preliminary studies it was possible to verify the possibility of producing fiber-cement sheets by replacing 25% of the conventional used virgin long fiber by primary effluent treatment cellulose sludge. This amount of incorporation was tested on an industrial scale.more » Environmental parameters related to water and waste, as well as tests for checking the quality of the final product was performed. These control parameters involved total solids in suspension, dissolved salts, chlorides, sulphates, COD, metals content. In the product, parameters like moisture, density and strength were controlled. The results showed that it is possible to replace the virgin long fibers pulp by primary sludge without impacts in final product characteristics and on the environment. This work ensures the elimination of significant waste amounts, which are nowadays sent to landfill, as well as reduces costs associated with the standard raw materials use in the fiber-cement industrial sector.« less

Structural and Biological Characterization of a Capsular Polysaccharide Produced by Staphylococcus haemolyticus▿

PubMed Central

Flahaut, Sigrid; Vinogradov, Evgeny; Kelley, Kathryn A.; Brennan, Shannon; Hiramatsu, Keiichi; Lee, Jean C.

2008-01-01

The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFGSh) showed ≥57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLMSh genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: −3-α-l-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-β-d-Glc)-4-α-d-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent. PMID:18165309

Structural and biological characterization of a capsular polysaccharide produced by Staphylococcus haemolyticus.

PubMed

Flahaut, Sigrid; Vinogradov, Evgeny; Kelley, Kathryn A; Brennan, Shannon; Hiramatsu, Keiichi; Lee, Jean C

2008-03-01

The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFG(Sh)) showed > or = 57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLM(Sh) genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: -3-alpha-L-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-beta-D-Glc)-4-alpha-D-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent.

Remediation of metal-contaminated marine sediments using active capping with limestone, steel slag, and activated carbon: a laboratory experiment.

PubMed

Park, Seong-Jik; Kang, Ku; Lee, Chang-Gu; Choi, Jae-Woo

2018-05-18

The objectives of this study are to assess the effectiveness of limestone (LS), steel slag (SS), and activated carbon (AC) as capping materials to sequester trace metals including As, Cd, Cr, Cu, Ni, Pb, and Zn in heavily contaminated marine sediments and to minimize the release of these metals into the water column. A flat flow tank was filled with 10 mm of capping material, contaminated sediments, and seawater, and the metal concentrations were monitored over 32 d. After completion of the flow tank experiments, the sediments below the capping material were sampled and were sequentially extracted. SS effectively reduced the As, Cr, Cu, Ni, Pb, and particularly Cd elution from the contaminated sediments to the overlying seawater. Adsorption and surface precipitation were the key mechanisms for interrupting the release of cationic trace metals by SS. LS was appropriate for interrupting the release of only Cu and Pb with high hydrolysis reaction constants. AC capping could interrupt the release of Cr, Cu, Ni, and particularly Zn from the sediments by binding with the metals via electrostatic interaction. The results obtained from the sequential extraction revealed that LS capping is appropriate for stabilizing Zn, whereas AC is appropriate for Cd and Pb. LS, SS, and AC can be applied effectively for remediation of sediments contaminated by trace metals because it interrupts their release and stabilizes the trace metals in the sediments.

Pore Water PAH Transport in Amended Sediment Caps

NASA Astrophysics Data System (ADS)

Gidley, P. T.; Kwon, S.; Ghosh, U.

2009-05-01

Capping is a common remediation strategy for contaminated sediments that creates a physical barrier between contaminated sediments and the water column. Diffusive flux of contaminants through a sediment cap is small. However, under certain hydrodynamic conditions such as groundwater potential and tidal pumping, groundwater advection can accelerate contaminant transport. Hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) could be transported through the cap under advective conditions. To better understand PAH migration under these conditions, physical models of sediment caps were evaluated in the laboratory through direct measurement of pore water using solid phase micro-extraction with gas chromatography and mass spectrometry. Contaminated sediment and capping material was obtained from an existing Superfund site that was capped at Eagle Harbor, Washington. A PAH dissolution model linked to an advection-dispersion equation with retardation using published organic carbon-water partitioning coefficients (Koc) was compared to measured PAHs in the sediment and cap porewater of the physical model.

Morphometric analysis of pulp size in maxillary permanent central incisors correlated with age: An indirect digital study

PubMed Central

Ravindra, S. V.; Mamatha, G. P.; Sunita, J. D.; Balappanavar, Aswini Y.; Sardana, Varun

2015-01-01

Context: Teeth are hardest part of the body and are least affected by the taphonomic process. They are considered as one of the reliable methods of identification of a person in forensic sciences. Aim: The aim of the following study is to establish morphometeric measurements by AutoCad 2009 (Autodesk, Inc) of permanent maxillary central incisors in different age groups of Udaipur population. Setting and Design: Hospital-based descriptive cross-sectional study carried out in Udaipur. Materials and Methods: A study was carried out on 308 subjects of both genders with the age range of 9-68 years. Standardized intra-oral radiographs were made by paralleling technique and processed. The radiographs were scanned and the obtained images were standardized to the actual size of radiographic film. This was followed by measuring them using software AutoCad 2009. Statistical Analysis Used: F-test, post-hoc test, Pearson's correlation test. Results: For left maxillary central incisor, the total pulp area was found to be of 38.41 ± 12.88 mm and 14.32 ± 7.04 mm respectively. For right maxillary central incisor, the total pulp size was 38.39 ± 14.95 mm and 12.35 ± 5 mm respectively. Males (32.50, 32.87 mm2) had more pulp area when compared with females (28.82, 30.05 mm2). Conclusion: There was a decrease in total pulp area with increasing age which may be attributed to secondary dentin formation. PMID:26816461

A Chronology of Late-Glacial and Holocene Advances of Quelccaya Ice Cap, Peru, Based on 10Be and Radiocarbon Dating

NASA Astrophysics Data System (ADS)

Kelly, M. A.; Lowell, T. V.; Schaefer, J. M.

2007-12-01

The Quelccaya Ice Cap region in the southeastern Peruvian Andes (~13-14°S latitude) is a key location for the development of late-glacial and Holocene terrestrial paleoclimate records in the tropics. We present a chronology of past extents of Quelccaya Ice Cap based on ~thirty internally consistent 10Be dates of boulders on moraines and bedrock as well as twenty radiocarbon dates of organic material associated with moraines. Based on results from both dating methods, we suggest that significant advances of Quelccaya Ice Cap occurred during late-glacial time, at ~12,700-11,400 yr BP, and during Late Holocene time ~400-300 yr BP. Radiocarbon dating of organic material associated with moraines provides maximum and minimum ages for ice advances and recessions, respectively, thus providing an independent check on 10Be dates of boulders on moraines. The opportunity to use both 10Be and radiocarbon dating makes the Quelccaya Ice Cap region a potentially important low-latitude calibration site for production rates of cosmogenic nuclides. Our radiocarbon chronology provides a tighter constraint on maximum ages of late-glacial and Late Holocene ice advances. Upcoming field research will obtain organic material for radiocarbon dating to improve minimum age constrains for late-glacial and Late Holocene ice recessions.

[Results of 30 children treated under dental general anesthesia in pediatric dentistry].

PubMed

Chen, Xu; Liu, Yao; Jin, Shi-fu; Zhang, Qian; Jin, Xuan-yu

2008-12-01

To determine the age and sex characteristics of the children and type of dental procedures performed under dental general anesthesia (DGA) and to assess the results after six months to one year's follow-up. A sample of 30 patients treated under dental general anesthesia (DGA) during 2006-2007 in the Department of Pediatric Dentistry of China Medical University was reviewed. All the teeth were treated one time. The dental procedures performed included caries restoration, indirect pulp capping, pulpotomy, root canal therapy (RCT) and dental extraction. Oral prophylaxis and topical fluoride applications were performed on all teeth. Pit and fissure sealing was performed on all healthy premolars and molars. SPSS10.0 software package was used for statistical analysis. Chi-square test was used to analyze the difference of the sex distribution in different age group and the difference of dental procedures performed between the primary teeth and the permanent teeth. The age of the patients ranged from 19 months to 14 years. The mental retardation patients accounted for 10% and mental healthy patients accounted for 90% of the sample studied. Males were more than females with the ratio about 2 to 1 in each age group. The dental procedures performed were caries restoration (18.67%), indirect pulp capping (23.26%), pulpotomy (0.77%), RCT (29.16%), dental extractions (2.05%) and fissure sealants (26.09%). The percentage of RCT was higher than that of caries restoration in the primary teeth, whereas the result was opposite as for the permanent teeth as indicated by Chi-square test (X(2)=11.630, P=0.001). New dental caries was not found except 2 patients who suffered from dysnoesia and were not cooperative to have regular examination. Fillings were lost in 3 cases, with 3 anterior teeth and 2 posterior teeth after RCT. All the children could cooperate except two mental retardation patients during the follow-up visit. Caries restoration and RCT are the most frequently performed procedures in pediatric patients using DGA. This indicates the need to design and implement integrate control and prevention programs for special pediatric patients. DGA is a safe and effective behavior management technique to treat uncooperative children.

Phase Composition Control of Calcium Phosphate Nanoparticles for Tunable Drug Delivery Kinetics and Treatment of Osteomyelitis. Part 1: Preparation and Drug Release

PubMed Central

Uskoković, Vuk; Desai, Tejal A.

2012-01-01

Developed in this study is a multifunctional material for simultaneous osseoinduction and drug delivery, potentially applicable in the treatment of osteomyelitis. It is composed of agglomerates of nanoparticles of calcium phosphate (CAP) with different monophasic contents. The drug loading capacity and the release kinetics were investigated on two model drug compounds with different chemical structures, sizes and adsorption propensities: bovine serum albumin and fluorescein. Loading of CAP powders with small molecule drugs was achieved by physisorption and desiccation-induced agglomeration of nanoparticulate subunits into microscopic blocks. The material dissolution rate and the drug release rate depended on the nature of the CAP phase, decreasing from monocalcium phosphate to monetite to amorphous CAP and calcium pyrophosphate to hydroxyapatite. The sustained release of the two model drugs was shown to be directly relatable to the degradation rate of CAP carriers. It was demonstrated that the degradation rate of the carrier and the drug release kinetics could be made tunable within the time scale of 1–2 h for the most soluble CAP phase, monocalcium phosphate, to 1–2 years for the least soluble one, hydroxyapatite. From the standpoint of antibiotic therapy for osteomyelitis, typically lasting for six weeks, the most prospective CAP powder was amorphous CAP with its release time scale for a small organic molecule, the same category to which antibiotics belong, of 1 – 2 months under the conditions applied in our experiments. By combining these different CAP phases in various proportions, drug release profiles could be tailored to the therapeutic occasion. PMID:23115118

Evidence of natural occurrence of the banned antibiotic chloramphenicol in herbs and grass.

PubMed

Berendsen, Bjorn; Stolker, Linda; de Jong, Jacob; Nielen, Michel; Tserendorj, Enkhtuya; Sodnomdarjaa, Ruuragchas; Cannavan, Andrew; Elliott, Christopher

2010-07-01

Chloramphenicol (CAP), a broad-spectrum antibiotic, was detected in several herb and grass samples from different geographic origins. Due to its suspected carcinogenicity and linkages with the development of aplastic anemia in humans, CAP is banned for use in food-producing animals in the European Union (EU) and many other countries. However, products of animal origin originating from Asian countries entering the European market are still found noncompliant (containing CAP) on a regular basis, even when there is no history of chloramphenicol use in these countries. A possible explanation for the continued detection of these residues is the natural occurrence of CAP in plant material which is used as animal feed, with the consequent transfer of the substance to the animal tissues. Approximately 110 samples were analyzed using liquid chromatography coupled with mass spectrometric detection. In 26 samples, the presence of CAP was confirmed using the criteria for banned substances defined by the EU. Among other plant materials, samples of the Artemisia family retrieved from Mongolia and from Utah, USA, and a therapeutic herb mixture obtained from local stores in the Netherlands proved to contain CAP at levels ranging from 0.1 to 450 microg/kg. These findings may have a major impact in relation to international trade and safety to the consumer. The results of this study demonstrate that noncompliant findings in animal-derived food products may in part be due to the natural occurrence of chloramphenicol in plant material. This has implications for the application of current EU, USA, and other legislation and the interpretation of analytical results with respect to the consideration of CAP as a xenobiotic veterinary drug residue and the regulatory actions taken upon its detection in food.

Evidence of natural occurrence of the banned antibiotic chloramphenicol in herbs and grass

PubMed Central

Berendsen, Bjorn; de Jong, Jacob; Nielen, Michel; Tserendorj, Enkhtuya; Sodnomdarjaa, Ruuragchas; Cannavan, Andrew; Elliott, Christopher

2010-01-01

Chloramphenicol (CAP), a broad-spectrum antibiotic, was detected in several herb and grass samples from different geographic origins. Due to its suspected carcinogenicity and linkages with the development of aplastic anemia in humans, CAP is banned for use in food-producing animals in the European Union (EU) and many other countries. However, products of animal origin originating from Asian countries entering the European market are still found noncompliant (containing CAP) on a regular basis, even when there is no history of chloramphenicol use in these countries. A possible explanation for the continued detection of these residues is the natural occurrence of CAP in plant material which is used as animal feed, with the consequent transfer of the substance to the animal tissues. Approximately 110 samples were analyzed using liquid chromatography coupled with mass spectrometric detection. In 26 samples, the presence of CAP was confirmed using the criteria for banned substances defined by the EU. Among other plant materials, samples of the Artemisia family retrieved from Mongolia and from Utah, USA, and a therapeutic herb mixture obtained from local stores in the Netherlands proved to contain CAP at levels ranging from 0.1 to 450 µg/kg. These findings may have a major impact in relation to international trade and safety to the consumer. The results of this study demonstrate that noncompliant findings in animal-derived food products may in part be due to the natural occurrence of chloramphenicol in plant material. This has implications for the application of current EU, USA, and other legislation and the interpretation of analytical results with respect to the consideration of CAP as a xenobiotic veterinary drug residue and the regulatory actions taken upon its detection in food. PMID:20431869

Transport properties of nanocomposite and its simulation with L-R-C circuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gangopadhyay, Arnab, E-mail: agangulyphysics@gmail.com; Sarkar, Aditi, E-mail: agangulyphysics@gmail.com; Sarkar, A., E-mail: agangulyphysics@gmail.com

2014-04-24

The nano particles are represented in this communication by L-R-C equivalent circuit. The dc current voltage characteristics (CVC) of the proposed circuit have simulated using Circuit-Maker ® 2000. Experimental investigation on ZnO nano-composite with capping material gum acacia shows similar CVC. NPs are represented by C-R combinations to manifest the Coulomb blockade effect of a quantum dot. The capping material is represented by an inductor along with a resistance in series. Nine NPs with capping matrix are simulated. The dc current voltage characteristics (CVC) and gross feature of polarization nature obtained by experiment and simulation study are consistent.

Evaluation of a Commercially Available Hyaluronic Acid Hydrogel (Restylane) as Injectable Scaffold for Dental Pulp Regeneration: An In Vitro Evaluation.

PubMed

Chrepa, Vanessa; Austah, Obadah; Diogenes, Anibal

2017-02-01

Regenerative endodontic procedures (REPs) are viable alternatives for treating immature teeth, yet these procedures do not predictably lead to pulp-dentin regeneration. A true bioengineering approach for dental pulp regeneration requires the incorporation of a scaffold conducive with the regeneration of the pulp-dentin complex. Several materials have been proposed as scaffolds for REPs; nonetheless, the majority are not eligible for immediate clinical chairside use. Thus, the aim of this study was to evaluate Restylane, a Food and Drug Administration-approved hyaluronic acid-based gel, as possible scaffold for REPs. Stem cells of the apical papilla (SCAP) were cultured either alone or in mixtures with either Restylane or Matrigel scaffolds. Groups were cultured in basal culture medium for 6, 24, and 72 hours, and cell viability was assessed. For the mineralizing differentiation experiments, groups were cultured in differentiation medium either for 7 days and processed for alkaline phosphatase activity or for 14 days and processed for gene expression by using quantitative reverse-transcription polymerase chain reaction. SCAP in basal medium served as control. Cell encapsulation in either Restylane or Matrigel demonstrated reduced cell viability compared with control. Nonetheless, cell viability significantly increased in the Restylane group in the course of 3 days, whereas it decreased significantly in the Matrigel group. Restylane promoted significantly greater alkaline phosphatase activity and upregulation of dentin sialophosphoprotein, dentin matrix acidic phosphoprotein-1, and matrix extracellular phosphoglycoprotein, compared with control. A Food and Drug Administration-approved hyaluronic acid-based injectable gel promoted SCAP survival, mineralization, and differentiation into an odontoblastic phenotype and may be a promising scaffold material for REPs. Published by Elsevier Inc.

The use of differential scanning calorimetry for the evaluation of dental materials. I. Cements, cavity lining materials and anterior restorative materials.

PubMed

McCabe, J F; Wilson, H J

1980-03-01

Thermal changes occurring during the setting of restorative materials have been measured accurately using a differential scanning calorimeter. The results were used to evaluate setting characteristics. The heat of reaction and rate of heat output may be significant in determining thermal damage to the pulp. The heat capacity is related to thermal insulation properties. These properties have been determined and their effect on the efficacy of restorative materials discussed.

Energy and raw material potentials of wood residue in the Pacific Coast States: a summary of a preliminary feasibility investigation.

Treesearch

John B. Grantham; Eldon Estep; John M. Pierovich; Harold Tarkow; Thomas C. Adams

1974-01-01

Results are reported of a preliminary investigation of feasibility of using wood residue to meet energy and raw material needs in the Pacific Coast States. Magnitude of needs was examined and volume of logging-residue and unused mill residue was estimated. Costs of obtaining and preprocessing logging residue for energy and pulp and particle board raw material were...

Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures

NASA Astrophysics Data System (ADS)

Peng, Shouzhong; Wang, Mengxing; Yang, Hongxin; Zeng, Lang; Nan, Jiang; Zhou, Jiaqi; Zhang, Youguang; Hallal, Ali; Chshiev, Mairbek; Wang, Kang L.; Zhang, Qianfan; Zhao, Weisheng

2015-12-01

Spin-transfer-torque magnetic random access memory (STT-MRAM) attracts extensive attentions due to its non-volatility, high density and low power consumption. The core device in STT-MRAM is CoFeB/MgO-based magnetic tunnel junction (MTJ), which possesses a high tunnel magnetoresistance ratio as well as a large value of perpendicular magnetic anisotropy (PMA). It has been experimentally proven that a capping layer coating on CoFeB layer is essential to obtain a strong PMA. However, the physical mechanism of such effect remains unclear. In this paper, we investigate the origin of the PMA in MgO/CoFe/metallic capping layer structures by using a first-principles computation scheme. The trend of PMA variation with different capping materials agrees well with experimental results. We find that interfacial PMA in the three-layer structures comes from both the MgO/CoFe and CoFe/capping layer interfaces, which can be analyzed separately. Furthermore, the PMAs in the CoFe/capping layer interfaces are analyzed through resolving the magnetic anisotropy energy by layer and orbital. The variation of PMA with different capping materials is attributed to the different hybridizations of both d and p orbitals via spin-orbit coupling. This work can significantly benefit the research and development of nanoscale STT-MRAM.

Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures.

PubMed

Peng, Shouzhong; Wang, Mengxing; Yang, Hongxin; Zeng, Lang; Nan, Jiang; Zhou, Jiaqi; Zhang, Youguang; Hallal, Ali; Chshiev, Mairbek; Wang, Kang L; Zhang, Qianfan; Zhao, Weisheng

2015-12-11

Spin-transfer-torque magnetic random access memory (STT-MRAM) attracts extensive attentions due to its non-volatility, high density and low power consumption. The core device in STT-MRAM is CoFeB/MgO-based magnetic tunnel junction (MTJ), which possesses a high tunnel magnetoresistance ratio as well as a large value of perpendicular magnetic anisotropy (PMA). It has been experimentally proven that a capping layer coating on CoFeB layer is essential to obtain a strong PMA. However, the physical mechanism of such effect remains unclear. In this paper, we investigate the origin of the PMA in MgO/CoFe/metallic capping layer structures by using a first-principles computation scheme. The trend of PMA variation with different capping materials agrees well with experimental results. We find that interfacial PMA in the three-layer structures comes from both the MgO/CoFe and CoFe/capping layer interfaces, which can be analyzed separately. Furthermore, the PMAs in the CoFe/capping layer interfaces are analyzed through resolving the magnetic anisotropy energy by layer and orbital. The variation of PMA with different capping materials is attributed to the different hybridizations of both d and p orbitals via spin-orbit coupling. This work can significantly benefit the research and development of nanoscale STT-MRAM.

Effects of Surfactants on the Preparation of Nanocellulose-PLA Composites

PubMed Central

Immonen, Kirsi; Lahtinen, Panu; Pere, Jaakko

2017-01-01

Thermoplastic composite materials containing wood fibers are gaining increasing interest in the manufacturing industry. One approach is to use nano- or micro-size cellulosic fibrils as additives and to improve the mechanical properties obtainable with only small fibril loadings by exploiting the high aspect ratio and surface area of nanocellulose. In this study, we used four different wood cellulose-based materials in a thermoplastic polylactide (PLA) matrix: cellulose nanofibrils produced from softwood kraft pulp (CNF) and dissolving pulp (CNFSD), enzymatically prepared high-consistency nanocellulose (HefCel) and microcellulose (MC) together with long alkyl chain dispersion-improving agents. We observed increased impact strength with HefCel and MC addition of 5% and increased tensile strength with CNF addition of 3%. The addition of a reactive dispersion agent, epoxy-modified linseed oil, was found to be favorable in combination with HefCel and MC. PMID:29149057

Conversion of agricultural residues into activated carbons for water purification: Application to arsenate removal.

PubMed

Torres-Perez, Jonatan; Gerente, Claire; Andres, Yves

2012-01-01

The conversion of two agricultural wastes, sugar beet pulp and peanut hulls, into sustainable activated carbons is presented and their potential application for the treatment of arsenate solution is investigated. A direct and physical activation is selected as well as a simple chemical treatment of the adsorbents. The material properties, such as BET surface areas, porous volumes, elemental analysis, ash contents and pH(PZC), of these alternative carbonaceous porous materials are determined and compared with a commercial granular activated carbon. An adsorption study based on experimental kinetic and equilibrium data is conducted in a batch reactor and completed by the use of different models (intraparticle diffusion, pseudo-second-order, Langmuir and Freundlich) and by isotherms carried out in natural waters. It is thus demonstrated that sugar beet pulp and peanut hulls are good precursors to obtain activated carbons for arsenate removal.

Post STS-133 Evaluation of Main Flame Deflector Witness Materials

NASA Technical Reports Server (NTRS)

Long, Victoria

2011-01-01

NASA and USA Structures engineers submitted main flame deflector witness materials for evaluation after the launch of STS-133. The following items were submitted for analysis: HY-80 steel witness rods, 304 stainless steel caps, tungsten pistons, 17-4 precipitation hardened (PH) stainless steel and A-286 piston sleeves, Medtherm Corporation calorimeters, and Nanmac Corporation thermocouples. All of the items were photographed in order to document their condition after the launch of STS-133, and before they were reinstalled at the launch pad for future launches. The HY -80 witness rods, 304 stainless steel caps, and the piston sleeves were dimensionally measured in order to determine the amount of material lost during launch. Microstructural changes were observed in the HY-80 witness rod and 304 stainless steel cap metallographic samples due to the heat of the launch.

46 CFR 160.037-2 - Type.

Code of Federal Regulations, 2013 CFR

2013-10-01

... removable cap having a friction striking material on its top which may be exposed for use by pulling a tear strip. The signal is ignited by scraping the friction striker on top of the cap against the igniter...

46 CFR 160.037-2 - Type.

Code of Federal Regulations, 2014 CFR

2014-10-01

... removable cap having a friction striking material on its top which may be exposed for use by pulling a tear strip. The signal is ignited by scraping the friction striker on top of the cap against the igniter...

46 CFR 160.037-2 - Type.

Code of Federal Regulations, 2011 CFR

2011-10-01

... removable cap having a friction striking material on its top which may be exposed for use by pulling a tear strip. The signal is ignited by scraping the friction striker on top of the cap against the igniter...

46 CFR 160.037-2 - Type.

Code of Federal Regulations, 2012 CFR

2012-10-01

... removable cap having a friction striking material on its top which may be exposed for use by pulling a tear strip. The signal is ignited by scraping the friction striker on top of the cap against the igniter...

46 CFR 160.037-2 - Type.

Code of Federal Regulations, 2010 CFR

2010-10-01

... removable cap having a friction striking material on its top which may be exposed for use by pulling a tear strip. The signal is ignited by scraping the friction striker on top of the cap against the igniter...

Two New Fluorogenic Aptasensors Based on Capped Mesoporous Silica Nanoparticles to Detect Ochratoxin A

PubMed Central

Ribes, Àngela; Santiago‐Felipe, Sara; Bernardos, Andrea; Marcos, M. Dolores; Pardo, Teresa; Sancenón, Félix; Aznar, Elena

2017-01-01

Abstract Aptamers have been used as recognition elements for several molecules due to their great affinity and selectivity. Additionally, mesoporous nanomaterials have demonstrated great potential in sensing applications. Based on these concepts, we report herein the use of two aptamer‐capped mesoporous silica materials for the selective detection of ochratoxin A (OTA). A specific aptamer for OTA was used to block the pores of rhodamine B‐loaded mesoporous silica nanoparticles. Two solids were prepared in which the aptamer capped the porous scaffolds by using a covalent or electrostatic approach. Whereas the prepared materials remained capped in water, dye delivery was selectively observed in the presence of OTA. The protocol showed excellent analytical performance in terms of sensitivity (limit of detection: 0.5–0.05 nm), reproducibility, and selectivity. Moreover, the aptasensors were tested for OTA detection in commercial foodstuff matrices, which demonstrated their potential applicability in real samples. PMID:29046860

Chemical approach for controlling nadimide cure temperature and rate

NASA Technical Reports Server (NTRS)

Lauver, R. W. (Inventor)

1985-01-01

Polyimide resins suitable for use as composite matrix materials are formed by copolymerization of maleic and norbornenyl end-capped monomers and oligomers. The copolymers can be cured at temperatures under about 300 C. by controlling the available concentration of the maleic end-capped reactant. This control can be achieved by adding sufficient amounts of said maleic reactant, or by chemical modification of either copolymer, to increase Diels-Alder retrogression of the norbornenyl-capped reactant and/or holding initiation and polymerization to a rate compatible with the availability of the maleic-capped reactant.

Introduction

NASA Astrophysics Data System (ADS)

Thorn, Ian; Au, Che On

We published the first edition of this book in 1995 and in the ensuing years change in the pulp and paper industry has continued at great speed. Pulp production, for instance, is moving from the forests of the USA and Nordic countries to South America. Similarly, new capacity in papermaking is moving east to Asia from North America and Europe. The last decade has seen much consolidation amongst both papermakers and their suppliers. In order to survive, the industry has had to rethink its strategies. Cost has become the leading topic of boardrooms throughout the world. Whether this means raw materials, energy, employee numbers or new investment, pressure on existing resources and those serving the industry becomes greater.

Mineral and Lithology Mapping of Drill Core Pulps Using Visible and Infrared Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, G. R., E-mail: G.Taylor@unsw.edu.au

2000-12-15

A novel approach for using field spectrometry for determining both the mineralogy and the lithology of drill core pulps (powders) is developed and evaluated. The methodology is developed using material from a single drillhole through a mineralized sequence of rocks from central New South Wales. Mineral library spectra are used in linear unmixing routines to determine the mineral abundances in drill core pulps that represent between 1 m and 3 m of core. Comparison with X-Ray Diffraction (XRD) analyses shows that for most major constituents, spectrometry provides an estimate of quantitative mineralogy that is as reliable as that provided bymore » XRD. Confusion between the absorption features of calcite and those of chlorite causes the calcite contents determined by spectrometry to be unreliable. Convex geometry is used to recognize the spectra of those samples that are extreme and are representative of unique lithologies. Linear unmixing is used to determine the abundance of these lithologies in each drillhole sample and these abundances are used to interpret the geology of the drillhole. The interpreted geology agrees well with conventional drillhole logs of the visible geology and photographs of the split core. The methods developed provide a quick and cost-effective way of determining the lithology and alteration mineralogy of drill core pulps.« less

Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp.

PubMed

Bayr, S; Ojanperä, M; Kaparaju, P; Rintala, J

2014-10-01

In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55°C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH4-N and/or free NH3) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m(3)d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm(3)/kg VS(fed). On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500-680 dm(3)/kg VS(fed)). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analysis of the dentin-pulp complex in teeth submitted to orthodontic movement in rats

PubMed Central

MASSARO, Camila da Siveira; CONSOLARO, Renata Bianco; SANTAMARIA, Milton; CONSOLARO, Maria Fernanda Martins-Ortiz; CONSOLARO, Alberto

2009-01-01

ABSTRACT In order to microscopically analyze the pulpal effects of orthodontic movement, 49 maxillary first molars of rats were submitted to orthodontic appliance composed of a closed coil spring anchored to the maxillary incisors, placed for the achievement of mesial movement. Material and Methods: Ten animals were used as the control group and were not submitted to orthodontic force; the other animals were divided into groups according to the study period of tooth movement, namely 1, 2, 3, 4, 5, 6 and 7 days. The investigation of pulp and periodontal changes included hyalinization, fibrosis, reactive dentin and vascular congestion. Statistical evaluation was performed between control and experimental groups and between periods of observation using non-parametric chi-square, Kruskal-Wallis and Dunn tests. Results: There was no statistically significant difference concerning pulpal changes between control and experimental groups nor between periods of observation. The control group, at 3 and 5 days, revealed greater hyalinization of the periodontal ligament (p<0.05), whereas root resorption was significantly greater at 5 and 7 days (p<0.05). Conclusion: No morphological change from the effect of induced tooth movement could be found in the dentin-pulp complex. In addition, no inflammatory or pulp degeneration, detectable in optical microscopy, was found in experimental groups. PMID:21499653

Sensory descriptive quantitative analysis of unpasteurized and pasteurized juçara pulp (Euterpe edulis) during long-term storage

PubMed Central

da Silva, Paula Porrelli Moreira; Casemiro, Renata Cristina; Zillo, Rafaela Rebessi; de Camargo, Adriano Costa; Prospero, Evanilda Teresinha Perissinotto; Spoto, Marta Helena Fillet

2014-01-01

This study evaluated the effect of pasteurization followed by storage under different conditions on the sensory attributes of frozen juçara pulp using quantitative descriptive analysis (QDA). Pasteurization of packed frozen pulp was performed by its immersion in stainless steel tank containing water (80°C) for 5 min, followed by storage under refrigerated and frozen conditions. A trained sensory panel evaluated the samples (6°C) on day 1, 15, 30, 45, 60, 75, and 90. Sensory attributes were separated as follows: appearance (foamy, heterogeneous, purple, brown, oily, and creamy), aroma (sweet and fermented), taste (astringent, bitter, and sweet), and texture (oily and consistent), and compared to a reference material. In general, unpasteurized frozen pulp showed the highest score for foamy appearance, and pasteurized samples showed highest scores to creamy appearance. Pasteurized samples remained stable regarding brown color development while unpasteurized counterparts presented increase. Color is an important attribute related to the product identity. All attributes related to taste and texture remained constant during storage for all samples. Pasteurization followed by storage under frozen conditions has shown to be the best conservation method as samples submitted to such process received the best sensory evaluation, described as foamy, slightly heterogeneous, slightly bitter, and slightly astringent. PMID:25473489

Sensory descriptive quantitative analysis of unpasteurized and pasteurized juçara pulp (Euterpe edulis) during long-term storage.

PubMed

da Silva, Paula Porrelli Moreira; Casemiro, Renata Cristina; Zillo, Rafaela Rebessi; de Camargo, Adriano Costa; Prospero, Evanilda Teresinha Perissinotto; Spoto, Marta Helena Fillet

2014-07-01

This study evaluated the effect of pasteurization followed by storage under different conditions on the sensory attributes of frozen juçara pulp using quantitative descriptive analysis (QDA). Pasteurization of packed frozen pulp was performed by its immersion in stainless steel tank containing water (80°C) for 5 min, followed by storage under refrigerated and frozen conditions. A trained sensory panel evaluated the samples (6°C) on day 1, 15, 30, 45, 60, 75, and 90. Sensory attributes were separated as follows: appearance (foamy, heterogeneous, purple, brown, oily, and creamy), aroma (sweet and fermented), taste (astringent, bitter, and sweet), and texture (oily and consistent), and compared to a reference material. In general, unpasteurized frozen pulp showed the highest score for foamy appearance, and pasteurized samples showed highest scores to creamy appearance. Pasteurized samples remained stable regarding brown color development while unpasteurized counterparts presented increase. Color is an important attribute related to the product identity. All attributes related to taste and texture remained constant during storage for all samples. Pasteurization followed by storage under frozen conditions has shown to be the best conservation method as samples submitted to such process received the best sensory evaluation, described as foamy, slightly heterogeneous, slightly bitter, and slightly astringent.

The effect of nanocrystalline cellulose on flow properties of fiber crop aqueous suspension.

PubMed

Gharehkhani, Samira; Seyed Shirazi, Seyed Farid; Yarmand, Hooman; Montazer, Elham; Kazi, Salim Newaz; Ibrahim, Rushdan; Ashjaei, Mehdi; Zulkifli, Nurin Wahidah Binti Mohd; Rahmati, Sadegh

2018-03-15

Nanocrystalline cellulose (NCC) a nature-based material, has gained significant attentions for its unique properties. The present study aims to investigate the flow behavior of cellulosic suspension containing non-wood pulp fibers and NCC, by means of rheological and pressure drop measurements. The NCC sample was prepared by sulfuric acid hydrolysis from Acacia mangium fibers. The rheological properties of kenaf/NCC suspensions were studied using viscosity and yield stress measurements. The pressure drop properties of the suspension flow were studied with respect to variation in flow velocity (0.4 m/s-3.6 m/s) and the NCC concentration (70 mg/l and 150 mg/l). The pressure drop results showed that the pulp suspension containing 150 mg/l NCC had higher drag reduction than kenaf suspension alone. The present insights into the flow of pulp/NCC suspension provide a new data and promote the application of NCC in industries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Odontoblast-Like Cells Differentiated from Dental Pulp Stem Cells Retain Their Phenotype after Subcultivation

PubMed Central

Baldión, Paula A.; Velandia-Romero, Myriam L.

2018-01-01

Odontoblasts, the main cell type in teeth pulp tissue, are not cultivable and they are responsible for the first line of response after dental restauration. Studies on dental materials cytotoxicity and odontoblast cells physiology require large quantity of homogenous cells retaining most of the phenotype characteristics. Odontoblast-like cells (OLC) were differentiated from human dental pulp stem cells using differentiation medium (containing TGF-β1), and OLC expanded after trypsinization (EXP-21) were evaluated and compared. Despite a slower cell growth curve, EXP-21 cells express similarly the odontoblast markers dentinal sialophosphoprotein and dentin matrix protein-1 concomitantly with RUNX2 transcripts and low alkaline phosphatase activity as expected. Both OLC and EXP-21 cells showed similar mineral deposition activity evidenced by alizarin red and von Kossa staining. These results pointed out minor changes in phenotype of subcultured EXP-21 regarding the primarily differentiated OLC, making the subcultivation of these cells a useful strategy to obtain odontoblasts for biocompatibility or cell physiology studies in dentistry. PMID:29670655

Influence of different combinations of wall materials on the microencapsulation of jussara pulp (Euterpe edulis) by spray drying.

PubMed

Santana, Audirene A; Cano-Higuita, Diana M; de Oliveira, Rafael A; Telis, Vânia R N

2016-12-01

The objective of this work was to study the spray drying of jussara pulp using ternary mixtures of gum Arabic (GA) and modified starch (MS) together with either whey protein concentrate (WPC) or soy protein isolate (SPI), as the carrier agents. Two experimental mixture designs and triangular response surfaces were used to evaluate the effects of the mixtures on the responses for powders formulated with GA:MS:WPC and GA:MS:SPI, respectively. The spray drying process was selected for each carrier agent mixture, aiming to maximum the process yield (PY), solubility (S), retention of total anthocyanins (RTA) and encapsulation efficiency (EE). It was shown that the ternary formulations showed higher PY, S and RTA than the pure and binary formulations, as well as good results for EE and a low moisture content, showing that the use of GA and MS together with either WPC or SPI provide better microencapsulation of the jussara pulp. Copyright © 2016 Elsevier Ltd. All rights reserved.

Valorization of residual Empty Palm Fruit Bunch Fibers (EPFBF) by microfluidization: production of nanofibrillated cellulose and EPFBF nanopaper.

PubMed

Ferrer, Ana; Filpponen, Ilari; Rodríguez, Alejandro; Laine, Janne; Rojas, Orlando J

2012-12-01

Different cellulose pulps were produced from sulfur-free chemical treatments of Empty Palm Fruit Bunch Fibers (EPFBF), a by-product from palm oil processing. The pulps were microfluidized for deconstruction into nanofibrillated cellulose (NFC) and nanopaper was manufactured by using an overpressure device. The morphological and structural features of the obtained NFCs were characterized via atomic force and scanning electron microscopies. The physical properties as well as the interactions with water of sheets from three different pulps were compared with those of nanopaper obtained from the corresponding NFC. Distinctive chemical and morphological characteristics and ensuing nanopaper properties were generated by the EPFBF fibers. The NFC grades obtained compared favorably with associated materials typically produced from bleached wood fibers. Lower water absorption, higher tensile strengths (107-137 MPa) and elastic modulus (12-18 GPa) were measured, which opens the possibility for valorization of such widely available bioresource. Copyright © 2012 Elsevier Ltd. All rights reserved.

Field measurements and modeling of dilution in the wake of a US navy frigate.

PubMed

Katz, C N; Chadwick, D B; Rohr, J; Hyman, M; Ondercin, D

2003-08-01

A field measurement and computer modeling effort was made to assess the dilution field of pulped waste materials discharged into the wake of a US Navy frigate. Pulped paper and fluorescein dye were discharged from the frigate's pulper at known rates. The subsequent particle and dye concentration field was then measured throughout the wake by a following vessel using multiple independent measures. Minimum dilution of the pulped paper reached 3.2 x 10(5) within 1900 m behind the frigate, or about 8 min after discharge. Independent measures typically agreed within 25% of one another and within 20% of model predictions. Minimum dilution of dye reached 2.3 x 10(5) at a down-wake distance of approximately 3500 m, or roughly 15 min. Comparison to model measurements were again within 20%. The field test was not only successful at characterizing wake dilution under one set of at-sea conditions, but was successful at validating the computer model used for assessing a wide range of ships and conditions.

Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells.

PubMed

Mestieri, Leticia Boldrin; Gomes-Cornélio, Ana Lívia; Rodrigues, Elisandra Márcia; Salles, Loise Pedrosa; Bosso-Martelo, Roberta; Guerreiro-Tanomaru, Juliane Maria; Tanomaru-Filho, Mário

2015-10-01

Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus. The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs). The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3 and kept in supplemented medium to obtain hDPCs adherent cultures. Cell characterization assays were performed to prove the osteogenic potential. The evaluated materials were: MTA Plus (MTAP); MTA Fillapex (MTAF) and FillCanal (FC). Biocompatibility was evaluated with MTT and Neutral Red (NR) assays, after hDPCs exposure for 24 h to different dilutions of each sealer extract (1:2, 1:3 and 1:4). Unexposed cells were the positive control (CT). Bioactivity was assessed by alkaline phosphatase (ALP) enzymatic assay in cells exposed for one and three days to sealer extracts (1:4 dilution). All data were analyzed by ANOVA and Tukey post-test (p≤0.05%). MTT and NR results showed suitable cell viability rates for MTAP at all dilutions (90-135%). Cells exposed to MTAF and FC (1:2 and 1:4 dilutions) showed significant low viability rate when compared to CT in MTT. The NR results demonstrated cell viability for all materials tested. In MTAP group, the cells ALP activity was similar to CT in one and three days of exposure to the material. MTAF and FC groups demonstrated a decrease in ALP activity when compared to CT at both periods of cell exposure. The hDPCs were suitable for the evaluation of new endodontic materialsin vitro. MTAP may be considered a promising material for endodontic treatments.

Composite laminate free-edge reinforcement with U-shaped caps. I - Stress analysis. II - Theoretical-experimental correlation

NASA Technical Reports Server (NTRS)

Howard, W. E.; Gossard, Terry, Jr.; Jones, Robert M.

1989-01-01

The present generalized plane-strain FEM analysis for the prediction of interlaminar normal stress reduction when a U-shaped cap is bonded to the edge of a composite laminate gives attention to the highly variable transverse stresses near the free edge, cap length and thickness, and a gap under the cap due to the manufacturing process. The load-transfer mechanism between cap and laminate is found to be strain-compatibility, rather than shear lag. In the second part of this work, the three-dimensional composite material failure criteria are used in a progressive laminate failure analysis to predict failure loads of laminates with different edge-cap designs; symmetric 11-layer graphite-epoxy laminates with a one-layer cap of kevlar-epoxy are shown to carry 130-140 percent greater loading than uncapped laminates, under static tensile and tension-tension fatigue loading.

Synthesization and characterization of poly(lactic-co-glycolic acid) / calcium phosphate bone cement from crab shells

NASA Astrophysics Data System (ADS)

Hanan, M. R. Abdul; Daud, N. M.; Ismail, L. H.; Saidin, S.

2017-05-01

An injectable calcium phosphate (CaP) bone cement has been widely used for musculoskeletal and bone disorder due to its biocompatible and osteoconductive properties. In this study, CaP was successfully synthesized from crab shells by a wet chemical route. Poly(lactic-co-glycolic acid) (PLGA) microspheres which have been produced through a double emulsion technique were incorporated into the CaP mixture for the purpose of bone cement solidification. The ratio of both compounds, CaP and PLGA, were set at 8:2. The CaP and PLGA/CaP bone cement were analyzed by ATR-FTIR, FESEM-EDX and contact angle analyses. The bone cement was composed of CaP and PLGA where the micro-powders of CaP were agglomerated on the PLGA microspheres. Addition of the PLGA has increased the hydrophilicity of the bone cement which will be beneficial for materials degradation and bone integration.

Local Regeneration of Dentin-Pulp Complex Using Controlled Release of FGF-2 and Naturally Derived Sponge-Like Scaffolds

PubMed Central

Kitamura, Chiaki; Nishihara, Tatsuji; Terashita, Masamichi; Tabata, Yasuhiko; Washio, Ayako

2012-01-01

Restorative and endodontic procedures have been recently developed in an attempt to preserve the vitality of dental pulp after exposure to external stimuli, such as caries infection or traumatic injury. When damage to dental pulp is reversible, pulp wound healing can proceed, whereas irreversible damage induces pathological changes in dental pulp, eventually requiring its removal. Nonvital teeth lose their defensive abilities and become severely damaged, resulting in extraction. Development of regeneration therapy for the dentin-pulp complex is important to overcome limitations with presently available therapies. Three strategies to regenerate the dentin-pulp complex have been proposed; regeneration of the entire tooth, local regeneration of the dentin-pulp complex from amputated dental pulp, and regeneration of dental pulp from apical dental pulp or periapical tissues. In this paper, we focus on the local regeneration of the dentin-pulp complex by application of exogenous growth factors and scaffolds to amputated dental pulp. PMID:22174717

Pulpal response to a new light-cured composite placed in etched glass-ionomer lined cavities.

PubMed

Hosoda, H; Inokoshi, S; Shimada, Y; Harnirattisai, C; Otsuki, M

1991-01-01

This study evaluated the pulp biocompatability of a new light-cured composite resin which was placed in etched glass-ionomer-lined cavities of monkey teeth. The pulpal response to this material was less than that to zinc-oxide eugenol cement in each observation period. Therefore this material seems to meet acceptable biocompatability standards in nonhuman primates.

Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

PubMed Central

Ibañez-Cabellos, José Santiago; de Cutanda, Sergio Bañuls-Sánchez; Berenguer-Pascual, Ester; Beltrán-García, Jesús; García-López, Eva; Pallardó, Federico V.; García-Giménez, José Luis; Pallarés-Sabater, Antonio; Zarzosa-López, Ignacio; Monterde, Manuel

2017-01-01

Human dental pulp stem cells (HDPSCs) are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white), an epoxy resin sealant (AH-Plus cement), and an MTA-based cement sealer (MTA-Fillapex). Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed. PMID:28751918

Dissolution profile of dolomite in chloric acid solution: The effect of chloric acid concentration and pulp density

NASA Astrophysics Data System (ADS)

Solihin, Indriani, Mubarok, M. Zaki

2018-05-01

Dolomite is one of carbonate minerals that contain magnesium. Magnesium is important element used in many aspects of life such as cofactor of many enzymes in human body, nutrient for plants, and raw material in automotive industry. Dolomite can be processed through low temperature process to obtain magnesium and calcium oxide that is needed in important applications such as base material for making drugs, raw material in the synthesize slow release fertilizer, materials for fire retardant, component for catalyst, etc. One of the important step of this low temperature process is dissolution of dolomite. Optimizing the dissolution process determines the % extraction of magnesium and calcium oxide from dolomite. The dissolution of dolomite from Gresik, East Java Provence Indonesia, in chloric acid solution has been conducted. Chloric acid concentration and pulp density are the variables that were observed. The dissolution of magnesium and calcium from Gresik dolomite was found to be very fast. The stable stage of dissolution can be reached for 5-10 seconds. The % extraction is mainly determined by the molar ratio of chloric acid / dolomite. At molar ratio of chloric acid / dolomite equal or above stoichiometric of dolomite dissolution, % extraction of magnesium is almost 100 %.

Lactic Acid Fermentation of Cactus Cladodes (Opuntia ficus-indica L.) Generates Flavonoid Derivatives with Antioxidant and Anti-Inflammatory Properties.

PubMed

Filannino, Pasquale; Cavoski, Ivana; Thlien, Nadia; Vincentini, Olimpia; De Angelis, Maria; Silano, Marco; Gobbetti, Marco; Di Cagno, Raffaella

2016-01-01

Cactus pear (Opuntia ficus-indica L.) is widely distributed in the arid and semi-arid regions throughout the world. In the last decades, the interest towards vegetative crop increased, and cladodes are exploited for nutraceutical and health-promoting properties. This study aimed at investigating the capacity of selected lactic acid bacteria to increase the antioxidant and anti-inflammatory properties of cactus cladodes pulp, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. Preliminarily, the antioxidant activity was determined through in vitro assays. Further, it was confirmed through ex vivo analysis on intestinal Caco-2/TC7 cells, and the profile of flavonoids was characterized. Cactus cladode pulp was fermented with lactic acid bacteria, which were previously selected from plant materials. Chemically acidified suspension, without bacterial inoculum and incubated under the same conditions, was used as the control. Lactobacillus plantarum CIL6, POM1 and 1MR20, Lactobacillus brevis POM2 and POM4, Lactobacillus rossiae 2LC8 and Pediococcus pentosaceus CILSWE5 were the best growing strains. Fermentation of cladode pulp with L. brevis POM2 and POM4 allowed the highest concentration of γ-amino butyric acid. Lactic acid fermentation had preservative effects (P<0.05) on the levels of vitamin C and carotenoids. Two flavonoid derivatives (kaemferol and isorhamnetin) were identified in the ethyl acetate extracts, which were considered to be the major compounds responsible for the increased radical scavenging activity. After inducing oxidative stress by IL-1β, the increased antioxidant activity (P<0.05) of fermented cladode pulp was confirmed using Caco-2/TC7 cells. Fermented cladode pulp had also immune-modulatory effects towards Caco-2 cells. Compared to the control, fermented cladode pulp exhibited a significantly (P<0.05) higher inhibition of IL-8, TNFα and prostaglandins PGE2 synthesis. The highest functional effect was found using ethyl acetate extracts. In conclusion, fermentation, especially with L. plantarum strains and L. brevis POM4, enhanced the antioxidant and immune-modulation features of cladode pulp.

Lactic Acid Fermentation of Cactus Cladodes (Opuntia ficus-indica L.) Generates Flavonoid Derivatives with Antioxidant and Anti-Inflammatory Properties

PubMed Central

Filannino, Pasquale; Cavoski, Ivana; Thlien, Nadia; Vincentini, Olimpia; De Angelis, Maria; Silano, Marco; Gobbetti, Marco; Di Cagno, Raffaella

2016-01-01

Cactus pear (Opuntia ficus-indica L.) is widely distributed in the arid and semi-arid regions throughout the world. In the last decades, the interest towards vegetative crop increased, and cladodes are exploited for nutraceutical and health-promoting properties. This study aimed at investigating the capacity of selected lactic acid bacteria to increase the antioxidant and anti-inflammatory properties of cactus cladodes pulp, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. Preliminarily, the antioxidant activity was determined through in vitro assays. Further, it was confirmed through ex vivo analysis on intestinal Caco-2/TC7 cells, and the profile of flavonoids was characterized. Cactus cladode pulp was fermented with lactic acid bacteria, which were previously selected from plant materials. Chemically acidified suspension, without bacterial inoculum and incubated under the same conditions, was used as the control. Lactobacillus plantarum CIL6, POM1 and 1MR20, Lactobacillus brevis POM2 and POM4, Lactobacillus rossiae 2LC8 and Pediococcus pentosaceus CILSWE5 were the best growing strains. Fermentation of cladode pulp with L. brevis POM2 and POM4 allowed the highest concentration of γ-amino butyric acid. Lactic acid fermentation had preservative effects (P<0.05) on the levels of vitamin C and carotenoids. Two flavonoid derivatives (kaemferol and isorhamnetin) were identified in the ethyl acetate extracts, which were considered to be the major compounds responsible for the increased radical scavenging activity. After inducing oxidative stress by IL-1β, the increased antioxidant activity (P<0.05) of fermented cladode pulp was confirmed using Caco-2/TC7 cells. Fermented cladode pulp had also immune-modulatory effects towards Caco-2 cells. Compared to the control, fermented cladode pulp exhibited a significantly (P<0.05) higher inhibition of IL-8, TNFα and prostaglandins PGE2 synthesis. The highest functional effect was found using ethyl acetate extracts. In conclusion, fermentation, especially with L. plantarum strains and L. brevis POM4, enhanced the antioxidant and immune-modulation features of cladode pulp. PMID:27023062

Spectrophotometric Evaluation of the Pulpal Peroxide Levels in Intact and Restored Teeth - An Invitro Study.

PubMed

Patri, Gaurav; Acharya, Gourismita; Agrawal, Pratik; Panda, Vijeta

2016-08-01

Hydrogen peroxide (30%) is a commonly used "in office" bleaching agent. Deleterious effects of hydrogen peroxide on the pulp have been observed. The present study was conducted with the aim to evaluate the penetration of 30% hydrogen peroxide into the pulp chamber through intact teeth and through the surface of teeth, restored with either hybrid composite or Resin Modified Glass Ionomer Cement (RMGIC). Sixty extracted human maxillary central incisors were selected and divided into six groups. Two groups were restored with hybrid composite resin and two with RMGIC, while two groups were left intact. The teeth with acetate buffer solution in their pulp cavity were then immersed in either 30% hydrogen peroxide or distilled water depending upon the group, for 60 minutes at 37°C. Then horseradish peroxidase and leucocrystal violet were added to the acetate buffer solution present in the pulp chamber after it was transferred to a test tube and the optical density of the resultant blue solution obtained was measured spectrophotometrically. The data obtained were analyzed using one way ANOVA and Student's t-test. The data obtained established that hydrogen peroxide penetrated into the pulp from the bleaching agent used. Hydrogen peroxide (30%) showed the highest pulpal peroxide level in teeth restored with RMGIC followed by teeth restored with hybrid composite resin and the least amount of penetration was observed in intact teeth. The amount of peroxide penetration into the tooth is more through restored tooth than intact tooth and is also dependant on the type of restorative materials used.

In-vitro Study on Temperature Changes in the Pulp Chamber Due to Thermo-Cure Glass Ionomer Cements

PubMed Central

van Duinen, Raimond NB; Shahid, Saroash; Hill, Robert

2016-01-01

The application of the Glass Ionomer Cements in clinical dentistry is recommended due to properties such as fluoride release, chemical adhesion to tooth, negligible setting shrinkage, and coefficient of thermal expansion close to tooth, low creep, and good color stability. However, the cement is vulnerable to early exposure to moisture due to slow setting characteristics. The uses of external energy such as ultrasound and radiant heat (Thermo-curing) have been reported to provide acceleration of the setting chemistry and enhance physical properties. Aim: The aim of this in vitro study was to analyze temperature changes in the pulpal chamber when using radiant heat to accelerate the setting of GICs. Material and Methods:The encapsulated GIC Equia Forte was used for this study. The temperature changes in the pulp were measured using thermocouple in the cavities which were 2,6 and 4,7mm deep with and without filling. Results:The results showed that a temperature rise (ΔT) in the pulp chamber was 3,7°C. ΔT for the 2.6mm and 4.7mm deep cavity and without placing any restoration the temperature was 4,2°C and 2,6°C respectively. After the restoration has been placed, the ΔT range in the pulp chamber was lower ranging from 1.9°C to 2.4°C. Conclusion: It could be concluded that Thermo-curing of the GIC during the setting is safe for the pulp and can be recommended in clinical practice. PMID:28275275

Effect of ITGA5 down-regulation on the migration capacity of human dental pulp stem cells

PubMed Central

Xu, Shuaimei; Cui, Li; Ma, Dandan; Sun, Wenjuan; Wu, Buling

2015-01-01

Background: The purpose of this study was to evaluate the role of integrin-α5 (ITGA5) in regulating the migration capacity of human dental pulp stem cells (hDPSCs), which might provide new evidence for understanding the repair and regeneration mechanisms of dental pulp tissues. Materials and methods: The enzyme digestion method was employed to isolate the hDPSCs from dental pulp tissues. The cell surface markers of hDPSCs were detected using flow cytometry analysis. Then the colony forming and multi-differentiation capacity of hDPSCs were evaluated. The lentivirus vector that carried the ITGA5 shRNA was constructed and real-time PCR was used to examine the effectiveness of ITGA5 shRNA lentivirus. Then transwell assay was performed to evaluate the impact of ITGA5 inhibition on the migration capability of hDPSCs. Results: Our results showed that the cells we isolated from the dental pulps were positive for mesenchymal stem cells biomarkers. In addition, the cells possessed both colony forming capacity and multi-differentiation potential. ITGA5 shRNA lentivirus could not only infect hDPSCs with high efficiency, but also down-regulate the expression level of ITGA5 mRNA significantly (P<0.01). The transwell assay revealed the number of cells that migrated to the lower chamber was significantly less in the ITGA5 shRNA group compared with that in the scrambled shRNA group (P=0.016). Conclusion: ITGA5 plays an important role in maintaining and regulating the normal migration capacity of hDPSCs. PMID:26823759

The use of mineral trioxide aggregate in endodontics.

PubMed

Casella, G; Ferlito, S

2006-03-01

Mineral trioxide aggregate (MTA), composed mainly of tricalcic silicate, tricalcic alluminate, bismuth oxide, is a particular endodontic cement. It is made of hydrophilic fine particles that harden in the presence of dampness or blood. It is biocompatible, radiopaque and it is harder to infiltrate, compared to classic materials for root filling such as amalgam, cements, Super-EBA, and IRM. and SEM studies of sections and copies in resin of root neoapices filled with amalgam, IRM, Super-EBA and MTA, as well as tests of microinfiltration have shown that MTA has excellent sealing capacities. It requires a working time of about 5 min and a hardening time that varies from 2 h and 45 min to 4 h according to the density of the air entrapped during mixing and the dampness of the receiving site. The long hardening time reduces internal tensions and the incidence of marginal infiltration, but it forces to definitively fill the tooth in the following sitting, with an interval of at least 3 days from the MTA application. Clinical experience shows how MTA is a material of choice in cases not only of endodontic surgery, apicectomy and retrograde filling but also in the sealing filling of perforations of the pulp chamber and of the root, stripping, internal reabsorptions, readaptations, lacerations, and apical transports. It has been used with success also in direct cappings and in apexifications instead of calcium hydroxide, leading to quicker therapies and more predictable The authors outline the operative phases of the different treatments proposed, make a survey of the most important studies published so far and hope that a new sealing cement with more reduced hardening times will soon be available.

Ion release and mechanical properties of calcium silicate and calcium hydroxide materials used for pulp capping.

PubMed

Natale, L C; Rodrigues, M C; Xavier, T A; Simões, A; de Souza, D N; Braga, R R

2015-01-01

To compare the ion release and mechanical properties of a calcium hydroxide (Dycal) and two calcium silicate (MTA Angelus and Biodentine) cements. Calcium and hydroxyl ion release in water from 24-h set cements were calculated from titration with HCl (n = 3). Calcium release after 7, 14, 21 and 28 days at pH 5.5 and 7.0 was measured using ICP-OES (n = 6). Flexural strength (FS) and modulus (E) were tested after 48-h storage, and compressive strength (CS) was tested after 48 h and 7 days (n = 10). Ion release and mechanical data were subjected to anova/Tukey and Kruskal-Wallis/Mann-Whitney tests, respectively (α = 0.05). Titration curves revealed that Dycal released significantly fewer ions in solution than calcium silicates (P < 0.001). Calcium release remained constant at pH 7.0, whilst at pH 5.5, it dropped significantly by 24% after 21 days (P < 0.05). At pH 5.5, MTA Angelus released significantly more calcium than Dycal (P < 0.01), whilst Biodentine had superior ion release than Dycal at pH 7.0 (P < 0.01). Biodentine had superior flexural strength, flexural modulus and compressive strength than the other cements, whilst MTA Angelus had higher modulus than Dycal (P < 0.001). Immediate calcium and hydroxyl ion release in solution was significantly lower for Dycal. In general, all materials released constant calcium levels over 28 days, but release from Dycal was significantly lower than Biodentine and MTA Angelus depending on pH conditions. Biodentine had substantially higher strength and modulus than MTA Angelus and Dycal, both of which demonstrated low stress-bearing capabilities. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Dry Kraft Pulping at Ambient Pressure for Cost Effective Energy Saving and Pollution Deduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yulin Deng; Art Ragauskas

Sponsored by the DOE Industrial Energy Efficiency Grand Challenge program, our research team at the Georgia Institute of Technology conducted laboratory studies and confirmed the concept of making wood pulp using a dry pulping technology. This technology is a new process different from any prior pulping technology used in Kraft and CTMP pulping. Three different kinds of dry pulping methods were investigated. (a) Dry Pulping at Atmospheric Pressure: The first one is to dry and bake the pretreated woodchips in a conventional oven at atmospheric pressure without the use of a catalyst. (b) Dry Pulping at Reduced Pressure: The secondmore » method is to dry the pretreated woodchips first in a vacuum oven in the presence of anthraquinone (AQ) as a pulping catalyst, followed by baking at elevated temperature. (c) Liquid Free Chemical Pulping, LFCP. The third method is to first remove the free water of pretreated woodchips, followed by dry pulping using a conventional Kraft pulping digester with AQ and triton as additives. Method one: Experimental results indicated that Dry Pulping at Atmospheric Pressure could produce pulp with higher brightness and lower bulk than conventional Kraft pulp. However, tensile strength of the acquired pulp is much lower than traditional Kraft pulp, and their Kappa number and energy consumption are higher than conventional Kraft pulp. By fully analyzing the results, we concluded that wood fibers might be damaged during the drying process at elevated temperature. The main reason for wood fiber damage is that a long drying time was used during evaporation of water from the woodchips. This resulted in an un-uniform reaction condition on the woodchips: the outside layer of the woodchips was over reacted while inside the woodchips did not reacted at all. To solve this problem, dry pulping at reduced pressure was investigated. Method two: To achieve uniform reaction throughout the entire reaction system, the water inside the pretreated woodchips was evaporated first under vacuum condition at low temperature. Then, the dry woodchips were baked at high temperature (120-130 C) at atmospheric pressure. The qualities of the pulp made with this method were improved compared to that made with method one. The pulp shows higher brightness and lower bulk than Kraft pulping. The tensile strength is significantly higher than the pulp made from the first method. Although the pulp is stronger than that of TMP pulp, it is still lower than conventional Kraft fiber. Method Three: The third dry method was done in a Kraft pulping digester at elevated pressure but without free liquid in the digester. With this method, pulp that has almost the same qualities as conventional Kraft pulp could be produced. The screen yield, Kappa number, fiber brightness, pulp strength and pulp bulk are almost identical to the conventional Kraft pulp. The key advantages of this dry pulping method include ca. 55 % of cooking energy saved during the pulping process, as high as 50 wt% of NaOH saving as well as 3 wt% of Na2S saving comparing to Kraft one. By analyzing fiber properties, yields, chemical and energy consumptions, we concluded that the dry pulping method based on Liquid Free Chemical Pulping, LFCP, could be very attractive for the pulp and paper industry. More fundamental studies and scale up trials are needed to fully commercialize the technology. We expect to conduct pilot trials between 12 to 24 months of period if the DOE or industry can provide continual research funding. Based on the technology we demonstrated in this report, several pilot trial facilities in the United States will be available after small modifications. For example, the Herty Foundation in Savannah, Georgia is one of these potential locations. DOE funding for continuous study and final lead to commercialization of the technique is important.« less

Effects of rooting and tree growth of selected woodland species on cap integrity in a mineral capped landfill site.

PubMed

Hutchings, T R; Moffat, A J; Kemp, R A

2001-06-01

The above and below ground growth of three tree species (Alnus glutinosa, Pinus nigra var. maritima and Acer pseudoplatanus) was studied on a containment landfill site at Waterford, Hertfordshire, UK. Tree root architecture was studied using soil inspection pits excavated next to 12 trees of each species and mapped in detail. Tree height was related to soil thickness over the compacted mineral cap. No roots entered the cap where soil thickness was 1.3 m, but a few roots, especially of alder, were observed within it when the soil cover was 1.0 m or less. Micromorphological analysis of undisturbed samples of the mineral cap suggested that roots exploited weaknesses in the cap rather than actively causing penetration into it. Alder roots were more tolerant of anaerobic conditions within the cap than the other species examined. The results confirm that mineral caps should be covered by 1.5 m of soil or soil-forming material if tree establishment is intended over a restored landfill site, unless protected by other parts of a composite capping system.

ASR/DEF-damaged bent caps : shear tests and field implications.

DOT National Transportation Integrated Search

2009-08-01

Over the last decade, a number of reinforced concrete bent caps within Houston, Texas have exhibited premature concrete damage (cracking, spalling and a loss of material : strength) due to alkali-silica reaction (ASR) and/or delayed ettringite format...

Mechanical Property Allowables Generated for the Solid Rocket Booster Composite Note Cap

NASA Technical Reports Server (NTRS)

Hodge, A. J.

2000-01-01

Mechanical property characterization was performed on AS4/3501-6 graphite/epoxy and SC350G syntactic foam for the SRB Composite Nose Cap Shuttle Upgrades Project. Lamina level properties for the graphite/epoxy were determined at room temperature, 240 F, 350 F, 480 F, 600 F, and 350 F after a cycle to 600 F. Graphite/epoxy samples were moisture conditioned prior to testing. The syntactic foam material was tested at room temperature, 350 F, and 480 F. A high-temperature test facility was developed at MSFC. Testing was performed with quartz lamp heaters and high resistance heater strips. The thermal history profile of the nose cap was simulated in order to test materials at various times during launch. A correlation study was performed with Southern Research Institute to confirm the test methodology and validity of test results. A-basis allowables were generated from the results of testing on three lots of material.

Cytotoxic effects of glass ionomer cements on human dental pulp stem cells correlate with fluoride release.

PubMed

Kanjevac, Tatjana; Milovanovic, Marija; Volarevic, Vladislav; Lukic, Miodrag L; Arsenijevic, Nebojsa; Markovic, Dejan; Zdravkovic, Nebojsa; Tesic, Zivoslav; Lukic, Aleksandra

2012-01-01

Glass ionomer cements (GICs) are commonly used as restorative materials. Responses to GICs differ among cell types and it is therefore of importance to thoroughly investigate the influence of these restorative materials on pulp stem cells that are potential source for dental tissue regeneration. Eight biomaterials were tested: Fuji I, Fuji II, Fuji VIII, Fuji IX, Fuji Plus, Fuji Triage, Vitrebond and Composit. We compared their cytotoxic activity on human dental pulp stem cells (DPSC) and correlated this activity with the content of Fluoride, Aluminium and Strontium ions in their eluates. Elution samples of biomaterials were prepared in sterile tissue culture medium and the medium was tested for toxicity by an assay of cell survival/proliferation (MTT test) and apoptosis (Annexin V FITC Detection Kit). Concentrations of Fluoride, Aluminium and Strontium ions were tested by appropriate methods in the same eluates. Cell survival ranged between 79.62% (Fuji Triage) to 1.5% (Fuji Plus) and most dead DPSCs were in the stage of late apoptosis. Fluoride release correlated with cytotoxicity of GICs, while Aluminium and Strontium ions, present in significant amount in eluates of tested GICs did not. Fuji Plus, Vitrebond and Fuji VIII, which released fluoride in higher quantities than other GICs, were highly toxic to human DPSCs. Opposite, low levels of released fluoride correlated to low cytotoxic effect of Composit, Fuji I and Fuji Triage.

A uni-extension study on the ultimate material strength and extreme extensibility of atherosclerotic tissue in human carotid plaques.

PubMed

Teng, Zhongzhao; Feng, Jiaxuan; Zhang, Yongxue; Sutcliffe, Michael P F; Huang, Yuan; Brown, Adam J; Jing, Zaiping; Lu, Qingsheng; Gillard, Jonathan H

2015-11-05

Atherosclerotic plaque rupture occurs when mechanical loading exceeds its material strength. Mechanical analysis has been shown to be complementary to the morphology and composition for assessing vulnerability. However, strength and stretch thresholds for mechanics-based assessment are currently lacking. This study aims to quantify the ultimate material strength and extreme extensibility of atherosclerotic components from human carotid plaques. Tissue strips of fibrous cap, media, lipid core and intraplaque hemorrhage/thrombus were obtained from 21 carotid endarterectomy samples of symptomatic patients. Uni-extension test with tissue strips was performed until they broke or slid. The Cauchy stress and stretch ratio at the peak loading of strips broken about 2mm away from the clamp were used to characterize their ultimate strength and extensibility. Results obtained indicated that ultimate strength of fibrous cap and media were 158.3 [72.1, 259.3] kPa (Median [Inter quartile range]) and 247.6 [169.0, 419.9] kPa, respectively; those of lipid and intraplaque hemorrhage/thrombus were 68.8 [48.5, 86.6] kPa and 83.0 [52.1, 124.9] kPa, respectively. The extensibility of each tissue type were: fibrous cap - 1.18 [1.10, 1.27]; media - 1.21 [1.17, 1.32]; lipid - 1.25 [1.11, 1.30] and intraplaque hemorrhage/thrombus - 1.20 [1.17, 1.44]. Overall, the strength of fibrous cap and media were comparable and so were lipid and intraplaque hemorrhage/thrombus. Both fibrous cap and media were significantly stronger than either lipid or intraplaque hemorrhage/thrombus. All atherosclerotic components had similar extensibility. Moreover, fibrous cap strength in the proximal region (closer to the heart) was lower than that of the distal. These results are helpful in understanding the material behavior of atherosclerotic plaques. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fabrication of nanobaskets by sputter deposition on porous substrates and uses thereof

NASA Technical Reports Server (NTRS)

Johnson, Paige Lea (Inventor); Teeters, Dale (Inventor)

2010-01-01

A method of producing a nanobasket and the applications or uses thereof. The method includes the steps of providing a substrate with at least one (1) pore having diameters of about one (1) nanometer to about ten (10) micrometers. Material is deposited by sputter-coating techniques along continuous edges of the pores to form a capped or partially capped nanotube or microtube structure, termed a nanobasket. Either a single material may be used to form nanobaskets over the pores or, alternately, a layered structure may be created wherein an initial material is deposited followed by one or more other materials to form nanobaskets over the pores.

Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

PubMed Central

Hu, Lei; Gao, Zhenhua; Zhu, Zhao; Zhang, Chunmei; Wang, Jinsong

2017-01-01

Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS) combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases. PMID:29387727

Heat pipe with improved wick structures

DOEpatents

Benson, David A.; Robino, Charles V.; Palmer, David W.; Kravitz, Stanley H.

2000-01-01

An improved planar heat pipe wick structure having projections formed by micromachining processes. The projections form arrays of interlocking, semi-closed structures with multiple flow paths on the substrate. The projections also include overhanging caps at their tops to increase the capillary pumping action of the wick structure. The capped projections can be formed in stacked layers. Another layer of smaller, more closely spaced projections without caps can also be formed on the substrate in between the capped projections. Inexpensive materials such as Kovar can be used as substrates, and the projections can be formed by electrodepositing nickel through photoresist masks.

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-01-01

Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Automated method for determining Instron Residual Seal Force of glass vial/rubber closure systems.

PubMed

Ludwig, J D; Nolan, P D; Davis, C W

1993-01-01

Instron Residual Seal Force (IRSF) of glass vial/rubber closure systems was determined using an Instron 4501 Materials Testing System. Computer programs were written to process raw data and calculate IRSF values. Preliminary experiments indicated both the appearance of the stress-deformation curves and precision of the derived IRSF values were dependent on the internal dimensions and top surface geometry of the cap anvil. Therefore, a series of five cap anvils varying in shape and dimensions were machined to optimize performance and precision. Vials capped with West 4416/50 PURCOAT button closures or Helvoet compound 6207 lyophilization closures were tested with each cap anvil. Cap anvils with spherical top surfaces and narrow internal dimensions produced more precise results and more uniform stress-deformation curves than cap anvils with flat top surfaces and wider internal dimensions.

40 CFR 430.76 - Pretreatment standards for existing sources (PSES).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

Effect of Residual Lignin Type and Amount on Bleaching of Kraft Pulp by Trametes versicolor

PubMed Central

Reid, Ian D.; Paice, Michael G.

1994-01-01

The white rot fungus Trametes (Coriolus) versicolor can delignify and brighten unbleached hardwood kraft pulp within a few days, but softwood kraft pulps require longer treatment. To determine the contributions of higher residual lignin contents (kappa numbers) and structural differences in lignins to the recalcitrance of softwood kraft pulps to biobleaching, we tested softwood and hardwood pulps cooked to the same kappa numbers, 26 and 12. A low-lignin-content (overcooked) softwood pulp resisted delignification by T. versicolor, but a high-lignin-content (lightly cooked) hardwood pulp was delignified at the same rate as a normal softwood pulp. Thus, the longer time taken by T. versicolor to brighten softwood kraft pulp than hardwood pulp results from the higher residual lignin content of the softwood pulp; possible differences in the structures of the residual lignins are important only when the lignin becomes highly condensed. Under the conditions used in this study, when an improved fungal inoculum was used, six different softwood pulps were all substantially brightened by T. versicolor. Softwood pulps whose lignin contents were decreased by extended modified continuous cooking or oxygen delignification to kappa numbers as low as 15 were delignified by T. versicolor at the same rate as normal softwood pulp. More intensive O2 delignification, like overcooking, decreased the susceptibility of the residual lignin in the pulps to degradation by T. versicolor. PMID:16349246

System and method for altering the tack of materials using an electrohydraulic discharge

DOEpatents

Banerjee, Sujit; Corcoran, Howard

2007-11-13

A system and method for altering the tack of a material, namely a polymer used as an adhesive, also known as stickies, or pitch. The present invention reduces the tack of the stickies and pitch by exposing the materials for a short duration to low-energy pulsed electrical discharges between a pair of electrodes that are submerged in a liquid medium, such as a fiber stream, water, a pulp slurry, or whitewater.

System and method for altering the tack of materials using an electrohydraulic discharge

DOEpatents

Banerjee, Sujit; Corcoran, Howard

2003-01-01

A system and method for altering the tack of a material, namely a polymer used as an adhesive, also known as stickies, or pitch. The present invention reduces the tack of the stickies and pitch by exposing the materials for a short duration to low-energy pulsed electrical discharges between a pair of electrodes that are submerged in a liquid medium, such as a fiber stream, water, a pulp slurry, or whitewater.

Effectiveness of radio waves application in modern general dental procedures: An update.

PubMed

Qureshi, Arslan; Kellesarian, Sergio Varela; Pikos, Michael A; Javed, Fawad; Romanos, Georgios E

2017-01-01

The purpose of the present study was to review indexed literature and provide an update on the effectiveness of high-frequency radio waves (HRW) application in modern general dentistry procedures. Indexed databases were searched to identify articles that assessed the efficacy of radio waves in dental procedures. Radiosurgery is a refined form of electrosurgery that uses waves of electrons at a radiofrequency ranging between 2 and 4 MHz. Radio waves have also been reported to cause much less thermal damage to peripheral tissues compared with electrosurgery or carbon dioxide laser-assisted surgery. Formation of reparative dentin in direct pulp capping procedures is also significantly higher when HRW are used to achieve hemostasis in teeth with minimally exposed dental pulps compared with traditional techniques for achieving hemostasis. A few case reports have reported that radiosurgery is useful for procedures such as gingivectomy and gingivoplasty, stage-two surgery for implant exposure, operculectomy, oral biopsy, and frenectomy. Radiosurgery is a relatively modern therapeutic methodology for the treatment of trigeminal neuralgia; however, its long-term efficacy is unclear. Radio waves can also be used for periodontal procedures, such as gingivectomies, coronal flap advancement, harvesting palatal grafts for periodontal soft tissue grafting, and crown lengthening. Although there are a limited number of studies in indexed literature regarding the efficacy of radio waves in modern dentistry, the available evidence shows that use of radio waves is a modernization in clinical dentistry that might be a contemporary substitute for traditional clinical dental procedures.

40 CFR 430.03 - Best management practices (BMPs) for spent pulping liquor, soap, and turpentine management, spill...

Code of Federal Regulations, 2012 CFR

2012-07-01

..., pulp washing, pulping liquor concentration, pulping liquor processing, and chemical recovery facilities... manager of pulping and chemical recovery operations, or other such responsible person designated by the mill manager who has knowledge of and responsibility for pulping and chemical recovery operations. (7...

40 CFR 430.03 - Best management practices (BMPs) for spent pulping liquor, soap, and turpentine management, spill...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., pulp washing, pulping liquor concentration, pulping liquor processing, and chemical recovery facilities... manager of pulping and chemical recovery operations, or other such responsible person designated by the mill manager who has knowledge of and responsibility for pulping and chemical recovery operations. (7...

Multiple piece turbine rotor blade

DOEpatents

Kimmel, Keith D.; Plank, William L.

2016-07-19

A spar and shell turbine rotor blade with a spar and a tip cap formed as a single piece, the spar includes a bottom end with dovetail or fir tree slots that engage with slots on a top end of a root section, and a platform includes an opening on a top surface for insertion of the spar in which a shell made from an exotic high temperature resistant material is secured between the tip cap and the platform. The spar is tapered to form thinner walls at the tip end to further reduce the weight and therefore a pulling force due to blade rotation. The spar and tip cap piece is made from a NiAL material to further reduce the weight and the pulling force.

Substrates and materials used for nesting by North American Osmia bees (Hymenoptera: Apiformes: Megachilidae)

Treesearch

James H. Cane; Terry L. Griswold; Frank D. Parker

2007-01-01

Nesting substrates and construction materials are compared for 65 of North America's 139 described native species of Osmia bees. Most accounts report Osmia bees nesting in preexisting cavities in dead wood or pithy stems such as elderberry (Sambucus spp.), with cell partitions and plugs made from a pulp of finely masticated leaf tissue. Mud is widely used by...

Evaluation of the Snap Sampler for Sampling Ground Water Monitoring Wells for VOCs and Explosives

DTIC Science & Technology

2007-08-01

prevent losses due to sorption . The time needed for equilibration will depend on the sampling device (and the materials in the sampler), the physical...bottles contain a perfluoroalkoxy ( PFA ) Teflon-coated spring mechanism that is connected to PFA Teflon end caps at both ends of the bottles...materials: polyvinylidene fluoride (PVDF) Kynar tubing or PFA Teflon tubing. These samplers are deployed in the well with the end caps of the bottle

Damage Tolerance Predictions for Spar Web Cracking in a Diminishing Stress Field

DTIC Science & Technology

2011-12-01

specimen crack. ....................... 40  28 NASGRO material file inputs for 7075 -T6 aluminum . .................................... 43  29 AFGROW...2024-T3511 aluminum end caps riveted to stiffened 7075 -T6 sheet metal aluminum webs. The cap-to-web attachment consisted of a double row of MS20470D8...section stress constant as the cracks 43 Fig. 28 NASGRO material file inputs for 7075 -T6 aluminum . grow. In this case, cracks are assumed to

Aesthetic treatment of discoloration of nonvital teeth.

PubMed

Miara, P

1995-09-01

Attempts to treat discoloration in nonvital teeth were first reported a century ago. This article discusses two potential causes of nonvital tooth discoloration-trauma and endodontic treatment-along with a step-by-step clinical procedure for treatment of the discoloration. In trauma, hemoglobin is released into the tissues; iron oxides, formed by oxygen and iron in hemoglobin, cause discoloration and swelling that infringes on pulp space, forcing the pulp to recede with a potential loss of tooth vitality. After endodontic treatment, either hemorrhaging, materials used, or incomplete removal and breakdown of necrotic tissue may cause staining. The learning objective of this article is to review the causes and the prevention/treatment of discoloration in nonvital teeth.

H2O grain size and the amount of dust in Mars' residual north polar cap

NASA Technical Reports Server (NTRS)

Kieffer, Hugh H.

1990-01-01

In Mars' north polar cap, the probable composition of material residual from the annual condensation cycle is a mixture of fine dust and H2O grains of comparable size and abundance. However, metamorphism of such material will gradually lower its albedo by increasing the size of the H2O grains only. If the cap is undergoing net annual sublimation (as inferred from water vapor observations), late summer observations should be of old ice with H2O grain sizes of 100 microns or more. Ice of this granularity containing 30 percent fine dust has a reflectivity similar to that of dust alone; the observed albedo and computed ice grain size imply dust concentrations of 1 part per 1000 or less. The brightness of the icy areas conflicts with what would be expected for a residual cap deposited by an annual cycle similar to that observed by Viking and aged for thousands of years. The residual cap surface cannot be 'old dirty' ice. It could be old, coarse, and clean; or it could be young, fine, and dirty. This brings into question both the source of the late summer water vapor and the formation rate of laminated terrain.

Capillary Contact Angle in a Completely Wet Groove

NASA Astrophysics Data System (ADS)

Parry, A. O.; Malijevský, A.; Rascón, C.

2014-10-01

We consider the phase equilibria of a fluid confined in a deep capillary groove of width L with identical side walls and a bottom made of a different material. All walls are completely wet by the liquid. Using density functional theory and interfacial models, we show that the meniscus separating liquid and gas phases at two phase capillary coexistence meets the bottom capped end of the groove at a capillary contact angle θcap(L) which depends on the difference between the Hamaker constants. If the bottom wall has a weaker wall-fluid attraction than the side walls, then θcap>0 even though all the isolated walls are themselves completely wet. This alters the capillary condensation transition which is now first order; this would be continuous in a capped capillary made wholly of either type of material. We show that the capillary contact angle θcap(L) vanishes in two limits, corresponding to different capillary wetting transitions. These occur as the width (i) becomes macroscopically large, and (ii) is reduced to a microscopic value determined by the difference in Hamaker constants. This second wetting transition is characterized by large scale fluctuations and essential critical singularities arising from marginal interfacial interactions.

H2O grain size and the amount of dust in Mars' residual North polar cap

USGS Publications Warehouse

Kieffer, H.H.

1990-01-01

In Mars' north polar cap the probable composition of material residual from the annual condensation cycle is a mixture of fine dust and H2O grains of comparable size and abundance. However, metamorphism of such material will gradually lower its albedo by increasing the size of the H2O grains only. If the cap is undergoing net annual sublimation (as inferred from water vapor observations), late summer observations should be of old ice with H2O grain sizes of 100 ??m or more. Ice of this granularity containing 30% fine dust has a reflectivity similar to that of dust alone; the observed albedo and computed ice grain size imply dust concentrations of 1 part per 1000 or less. The brightness of the icy areas conflicts with what would be expected for a residual cap deposited by an annual cycle similar to that observed by Viking and aged for thousands of years. The residual cap surface cannot be "old dirty' ice. It could be old, coarse, and clean; or it could be young, fine, and dirty. This brings into question both the source of the late summer water vapor and the formation rate of laminated terrain. -Author

Monoculture and polyculture: Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea)

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (...

Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea): Monoculture and polyculture production

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (...

EFFECTIVENESS OF CLAY POLYMER CAPPING MATERIAL IN ISOLATING ORGANIC AND INORGANIC SEDIMENT CONTAMINATION

EPA Science Inventory

The United States Environmental Protection Agency (U.S. EPA) National Risk Management Research Laboratory (NRMRL) has been funding the demonstration of sediment capping remediation design and assessment in the Anacostia River in Washington, D.C., through the Superfund Innovative ...

40 CFR 430.74 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

40 CFR 430.74 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp... mechanical pulp facilities where pulp and paper at groundwood mills are produced through the application of the thermo-mechanical process; mechanical pulp facilities where the integrated production of pulp and...

Automated method for determining Instron Residual Seal Force of glass vial/rubber closure systems. Part II. 13 mm vials.

PubMed

Ludwig, J D; Davis, C W

1995-01-01

Instron Residual Seal Force (IRSF) of 13 mm glass vial/rubber closure systems was determined using an Instron 4501 Materials Testing System and computerized data analysis. A series of three cap anvils varying in shape and dimensions were machined to optimize cap anvil performance. Cap anvils with spherical top surfaces and narrow internal dimensions produced uniform stress-deformation curves from which precise IRSF values were derived.

Damage of multilayer optics with varying capping layers induced by focused extreme ultraviolet beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jody Corso, Alain; Nicolosi, Piergiorgio; Nardello, Marco

2013-05-28

Extreme ultraviolet Mo/Si multilayers protected by capping layers of different materials were exposed to 13.5 nm plasma source radiation generated with a table-top laser to study the irradiation damage mechanism. Morphology of single-shot damaged areas has been analyzed by means of atomic force microscopy. Threshold fluences were evaluated for each type of sample in order to determine the capability of the capping layer to protect the structure underneath.

North-south geological differences between the residual polar caps on Mars

USGS Publications Warehouse

Thomas, P.C.; Malin, M.C.; Edgett, K.S.; Carr, M.H.; Hartmann, W.K.; Ingersoll, A.P.; James, P.B.; Soderblom, L.A.; Veverka, J.; Sullivan, R.

2000-01-01

Polar processes can be sensitive indicators of global climate, and the geological features associated with polar ice caps can therefore indicate evolution of climate with time. The polar regions on Mars have distinctive morphologic and climatologic features: thick layered deposits, seasonal CO2 frost caps extending to mid latitudes, and near-polar residual frost deposits that survive the summer. The relationship of the seasonal and residual frost caps to the layered deposits has been poorly constrained, mainly by the limited spatial resolution of the available data. In particular, it has not been known if the residual caps represent simple thin frost cover or substantial geologic features. Here we show that the residual cap on the south pole is a distinct geologic unit with striking collapse and erosional topography; this is very different from the residual cap on the north pole, which grades into the underlying layered materials. These findings indicate that the differences between the caps are substantial (rather than reflecting short-lived differences in frost cover), and so support the idea of long-term asymmetry in the polar climates of Mars.

Role of Angiogenesis in Endodontics: Contributions of Stem Cells and Proangiogenic and Antiangiogenic Factors to Dental Pulp Regeneration

PubMed Central

Saghiri, Mohammad Ali; Asatourian, Armen; Sorenson, Christine M.; Sheibani, Nader

2016-01-01

Introduction Dental pulp regeneration is a part of regenerative endodontics, which includes isolation, propagation, and re-transplantation of stem cells inside the prepared root canal space. The formation of new blood vessels through angiogenesis is mandatory to increase the survival rate of re-transplanted tissues. Angiogenesis is defined as the formation of new blood vessels from preexisting capillaries, which has great importance in pulp regeneration and homeostasis. Here the contribution of human dental pulp stem cells and proangiogenic and antiangiogenic factors to angiogenesis process and regeneration of dental pulp is reviewed. Methods A search was performed on the role of angiogenesis in dental pulp regeneration from January 2005 through April 2014. The recent aspects of the relationship between angiogenesis, human dental pulp stem cells, and proangiogenic and antiangiogenic factors in regeneration of dental pulp were assessed. Results Many studies have indicated an intimate relationship between angiogenesis and dental pulp regeneration. The contribution of stem cells and mechanical and chemical factors to dental pulp regeneration has been previously discussed. Conclusions Angiogenesis is an indispensable process during dental pulp regeneration. The survival of inflamed vital pulp and engineered transplanted pulp tissue are closely linked to the process of angiogenesis at sites of application. However, the detailed regulatory mechanisms involved in initiation and progression of angiogenesis in pulp tissue require investigation. PMID:25649306

Regenerative Endodontic Therapy in a Single Visit Using Platelet-rich Plasma and Biodentine in Necrotic and Asymptomatic Immature Molar Teeth: A Report of 3 Cases.

PubMed

Topçuoğlu, Gamze; Topçuoğlu, Hüseyin Sinan

2016-09-01

This report describes 3 successful single-visit regenerative endodontic therapy cases using platelet-rich plasma (PRP) and Biodentine (Septodont, Saint Maurdes Fossés, France) for 3 immature mandibular molar teeth, all with necrotic pulp, in 2 children aged 8 years and 1 aged 9 years. Three teeth were separately diagnosed as having a necrotic pulp. After preparation of the access cavity under rubber dam isolation, the necrotic pulp was removed, and each canal was irrigated with 2.5% sodium hypochlorite, sterile saline, and 17% EDTA solutions. Freshly prepared PRP was injected into each canal up to the cementoenamel junction, and Biodentine was placed directly over the PRP clot. Each access cavity was then restored with composite resin. Follow-up clinical examinations revealed negative responses to cold and electric pulp tests. None of the treated teeth were sensitive to percussion or palpation. Radiographic examination showed continued thickening of root canal walls and apical closure of the root apex of each tooth. Single-visit regenerative endodontic therapy can be considered in necrotic and asymptomatic immature permanent teeth. PRP and Biodentine may serve as scaffold and barrier materials in regenerative endodontic procedures. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry.

PubMed

Buyukkamaci, Nurdan; Koken, Emre

2010-11-15

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000m(3)/day range with 1000m(3)/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents. Copyright © 2010 Elsevier B.V. All rights reserved.

[Correlation between dental pulp demyelination degree and pain visual analogue scale scores data under acute and chronic pulpitis].

PubMed

Korsantiia, N B; Davarashvili, X T; Gogiashvili, L E; Mamaladze, M T; Tsagareli, Z G; Melikadze, E B

2013-05-01

The aim of study is the analysis of pulp nerve fibers demyelination degree and its relationship with Visual Analogue Scale (VAS) score that may be measured as objective criteria. Material and methods of study. Step I: electron micrografs of dental pulp simples with special interest of myelin structural changes detected in 3 scores system, obtained from 80 patients, displays in 4 groups: 1) acute and 2) chronic pulpitis without and with accompined systemic deseases, 20 patients in each group. Dental care was realized in Kutaisi N1 Dental clinic. Step II - self-reported VAS used for describing dental pain. All data were performed by SPSS 10,0 version statistics including Spearmen-rank and Mann-Whitny coefficients for examine the validity between pulp demyelination degree and pain intensity in verbal, numbered and box scales. Researched Data were shown that damaged myelin as focal decomposition of membranes and Schwann cells hyperthrophia correspond with acute dental pain intensity as Spearman index reported in VAS numbered Scales, myelin and axoplasm degeneration as part of chronic gangrenous pulpitis disorders are in direct correlation with VAS in verbal, numbered and behavioral Rating Scales. In fact, all morphological and subjective data, including psychomotoric assessment of dental painin pulpitis may be used in dental practice for evaluation of pain syndrome considered personal story.

A comprehensive program to develop correlations for physical properties of kraft black liquor. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, A.L.; Zaman, A.A.; Stoy, M.O.

A wide variety of experimental techniques have been used in this work, and many of these have been developed completely or improved significantly in the course of the research done during this program. Therefore, it is appropriate to describe these techniques in detail as a reference for future workers so that the techniques can be used in future work with little additional effort or so that the results reported from this program can be compared better with future results from other work. In many cases, the techniques described are for specific analytical instruments. It is recognized that these may bemore » superseded by future developments and improvements in instrumentation if a complete description of techniques used successfully in the past on other instrumentation is available. The total pulping and liquor preparation research work performed included chip and white liquor preparation, digestion, pulp washing, liquor and wash recovery, liquor sampling, weak liquor concentration in two steps to about 45--50% solids with an intermediate soap skimming at about 140F and 27--30% solids, determination of pulp yield and Kappa number, determination of total liquor solids, and a check on the total material balance for pulping. All other research was performed either on a sample of the weak black liquor (the combined black liquor and washes from the digester) or on the skimmed liquor that had been concentrated.« less

Lauryl Amine as heavy metal collector of boiler ash from pulp and paper mill waste

NASA Astrophysics Data System (ADS)

Sembiring, M. P.; Kaban, J.; Bangun, N.; Saputra, E.

2018-04-01

Theincreasing of demand of pulp and paper products, will following with the growing the pulp and paper industryand generate significant mill waste. The total waste reached 1/3 of the amount raw materials used and ash boiler is the waste with the largest percentage of 52%. For that it takes effort to manage the existing waste. The boiler ash contained the chemical elements, it can be utilized such as fertilizer, because it also contains transition metals in form of heavy metal such as Cadmium (Cd), Cobalt (Co), Chrome (Cr), Cupprum (Cu), Ferrum (Fe), Nickel (Ni), and Zinc (Zn), the use of boiler ash must follow the threshold specified by the Government. Several studies have been undertaken to reduce and extract heavy metals from ash and sand of the boiler by using carbon dioxide as its ligand. Eelectrochemical method was used to remove and recovery of heavy metals from the incenerator. This study focused on removal of heavy metals using Lauryl Amine as collector and three solvents namely Dichloromethane, Ethanol and n-Hexane. The treatmentswas able to extract the heavy metal and generally reduce the heavy metal content of ash boiler pulp and paper mill waste. The combination treatment used toreduce the heavy metal content of 5 gram Lauryl Amine collector in Dichloromethane solvent for 4 hours process time.

Reducing the risk of sensitivity and pulpal complications after the placement of crowns and fixed partial dentures.

PubMed

Brännström, M

1996-10-01

Sensitivity after cementation of a crown with glass-ionomer cement is often attributed to an adverse effect on the pulp by the luting agent. Most permanent restorative materials in common use today do not tend to irritate the pulp; the main cause of pulpal damage is infection, the bacteria originating in the smear layer or deep in the dental tubules, inaccessible to caries-excavating procedures. A poorly fitting provisional crown may expose cut dentin to the oral fluids, and mechanical trauma caused by frictional heat during preparation may also damage the pulp. The following precautions are recommended during precementation procedures to reduce the risk of an inflammatory response in the pulp: (1) The provisional crown should be well fitting, covering cervical dentin but not impinging on the periodontal tissues. The permanent crown should be cemented as soon as possible. (2) The superficial smear layer should be removed and the dentinal surface should be treated with an antibacterial solution before the provisional crown is placed. (3) To decrease dentinal permeability under the provisional crown, the dentinal surface should be covered with a liner that can be easily removed before final cementation. (4) to ensure optimal mircomechanical bonding, the dentinal surface should be thoroughly cleaned, and the dentin should be kept moist until cementation. (5) The occlusion should be carefully checked before cementation of the crown.

Development of Paper Products from Dried Sweetpotato Stems and Peanut Shells

NASA Technical Reports Server (NTRS)

McConnell, R.; Smith, R.; Jones, G.; Lu, J. Y.

1998-01-01

One of the goals of NASA's Advanced Life Support Program (ALS) for sustaining human life in space is to achieve a closed system in plant production and usage. That all inedible plant parts should be recycled or used in some way. A Tuskegee University team researching sweetpotato and peanut for ALS has developed paper products from dried sweet-potato stems and peanut shells. In this study, the sweet-potato stems and peanut shells were soaked separately in water for 48 hours. After 48 hours, researchers manually separated the pulp and the unusable parts. To form the paper, 160 g of pulp and water mixture was poured through a 15.1 cm (diameter) filtration funnel and the pulp was trapped on 15 cm (diameter) filter paper. The filter paper and pulp were dried in an air oven, and the filter paper was removed, An examination under a scanning electron microscope showed that the sweet-potato paper was composed of "fibers", whereas the peanut shell paper was composed of "blocks". Results of physical testing showed that the sweet-potato stem paper was stronger than the peanut shell paper. It is anticipated that there may be other uses of these products such as writing paper, bags and packaging material. Because of its biodegradability, it can be incorporated into the resource recycling system at the end of its use.

The introduction of the fungal D-galacturonate pathway enables the consumption of D-galacturonic acid by Saccharomyces cerevisiae.

PubMed

Biz, Alessandra; Sugai-Guérios, Maura Harumi; Kuivanen, Joosu; Maaheimo, Hannu; Krieger, Nadia; Mitchell, David Alexander; Richard, Peter

2016-08-18

Pectin-rich wastes, such as citrus pulp and sugar beet pulp, are produced in considerable amounts by the juice and sugar industry and could be used as raw materials for biorefineries. One possible process in such biorefineries is the hydrolysis of these wastes and the subsequent production of ethanol. However, the ethanol-producing organism of choice, Saccharomyces cerevisiae, is not able to catabolize D-galacturonic acid, which represents a considerable amount of the sugars in the hydrolysate, namely, 18 % (w/w) from citrus pulp and 16 % (w/w) sugar beet pulp. In the current work, we describe the construction of a strain of S. cerevisiae in which the five genes of the fungal reductive pathway for D-galacturonic acid catabolism were integrated into the yeast chromosomes: gaaA, gaaC and gaaD from Aspergillus niger and lgd1 from Trichoderma reesei, and the recently described D-galacturonic acid transporter protein, gat1, from Neurospora crassa. This strain metabolized D-galacturonic acid in a medium containing D-fructose as co-substrate. This work is the first demonstration of the expression of a functional heterologous pathway for D-galacturonic acid catabolism in Saccharomyces cerevisiae. It is a preliminary step for engineering a yeast strain for the fermentation of pectin-rich substrates to ethanol.

Direct measurement of time-dependent anesthetized in vivo human pulp temperature.

PubMed

Runnacles, Patrício; Arrais, Cesar Augusto Galvão; Pochapski, Marcia Thais; dos Santos, Fábio André; Coelho, Ulisses; Gomes, João Carlos; De Goes, Mário Fernando; Gomes, Osnara Maria Mongruel; Rueggeberg, Frederick Allen

2015-01-01

Human intrapupal tooth temperature is considered to be similar to that of the body (≈37 °C), although the actual temperature has never been measured. This study evaluated the in vivo, human, basal, coronal intrapulpal temperature of anesthetized upper first premolars. After approval of the local Ethics Committee was obtained (protocol no. 255,945), upper right and left first premolars requiring extraction for orthodontic reasons from 8 volunteers, ranging from 12 to 30 years old, received infiltrative and intraligamental anesthesia. The teeth (n=15) were isolated using rubber dam and a small, occlusal preparation was made using high-speed handpiece, under constant air-water spray, until a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system (Thermes WFI) was inserted directly into the coronal pulp. Once the probe was properly positioned and stable, real-time temperature data were continuously acquired for approximately 25 min. Data (°C) were subjected to 2-tailed, paired t-test (α=0.05), and the 95% confidence intervals for the initial and 25-min mean temperatures were also determined. The initial pulp temperature value (31.8±1.5 °C) was significantly lower than after 25-min (35.3±0.7 °C) (p<0.05). The 95% confidence interval for the initial temperature ranged from 31.0 to 32.6 °C and from 35.0 to 35.7 °C after 25 min. A slow, gradual temperature increase was observed after probe insertion until the pulp temperature reached a plateau, usually after 15 min. Consistent coronal, human, in vivo temperature values were observed and were slightly, but significantly below that of body core temperature. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Biodegradation of kraft lignin by a newly isolated anaerobic bacterial strain, Acetoanaerobium sp. WJDL-Y2.

PubMed

Duan, J; Huo, X; Du, W J; Liang, J D; Wang, D Q; Yang, S C

2016-01-01

An anaerobic kraft lignin (KL)-degrading bacterial strain was isolated from sludge of a pulp and paper mill. It was characterized as Acetoanaerobium sp. WJDL-Y2 by 16S rRNA gene sequencing. The maximum KL degradation capability of strain Y2 was determined to be 24·9% on a COD basis under an optimal condition with temperature of 31·5°C, initial pH of 6·8 and KL to nitrogen (as NH4 Cl) ratio of 6·5 by mass. Growth kinetic studies showed that the KL tolerance of strain Y2 was relatively high (Ki  = 8120·45 mg l(-1) ). Analysing KL degradation products by GC-MS revealed the formation of low-molecular-weight aromatic compounds (LMWACs), including benzene-propanoic acid, syringic acid and ferulic acid. This indicates that strain Y2 can oxidize lignin structure's p-hydroxyphenyl (H) units, guaiacyl (G) units and syringyl (S). In addition, the inoculated sample also contained low-molecular acid compounds, such as hexanoic acid, adipic acid and 2-hydroxybutyric acid, further validating strain Y2's ability to degrade KL. Kraft lignin containing effluents discharged from pulp and paper industries causes serious environmental pollution in developing countries. Due to the immense environmental adaptability and biochemical versatility, bacterial ligninolytic potential deserve to be studied for application in effluent treatment of pulp and paper industry. In this study, an anaerobic lignin-degrading bacterium, Acetoanaerobium sp. WJDL-Y2 (accession no. KF176997),was isolated from the sludge of a pulp and paper mill. Strain Y2 can play an important role in treating pulp and paper wastewater, as well as breaking down materials for biofuel and chemical production. © 2015 The Society for Applied Microbiology.

Assembly of Layered Monetite-Chitosan Nanocomposite and Its Transition to Organized Hydroxyapatite.

PubMed

Ruan, Qichao; Liberman, David; Zhang, Yuzheng; Ren, Dongni; Zhang, Yunpeng; Nutt, Steven; Moradian-Oldak, Janet

2016-06-13

Bioinspired synthesis of hierarchically structured calcium phosphate (CaP) material is a highly promising strategy for developing improved bone substitute materials. However, synthesis of CaP materials with outstanding mechanical properties still remains an ongoing challenge. Inspired by the formation of lamellar structure in nacre, we designed an organic matrix composed of chitosan and cis-butenediolic acid (maleic acid, MAc) that could assemble into a layered complex and further guide the mineralization of monetite crystals, resulting in the formation of organized and parallel arrays of monetite platelets with a brick-and-mortar structure. Using the layered monetite-chitosan composite as a precursor, we were able to synthesize hydroxyapatite (HAp) with multiscale hierarchically ordered structure via a topotactic phase transformation process. On the nanoscale, needlelike HAp crystallites assembled into organized bundles that aligned to form highly oriented plates on the microscale. On the large-scale level, these plates with different crystal orientations were stacked together to form a layered structure. The organized structures and composite feature yielded CaP materials with improved mechanical properties close to those of bone. Our study introduces a biomimetic approach that may be practical for the design of advanced, mechanically robust materials for biomedical applications.

Evaluation Of Sorption Materials For Use In Remediation Of Mercury-Contaminated Fresh Water Sediments

EPA Science Inventory

The purpose of this project is to characterize the extent of mercury methylation under conditions simulating those at a mercury-contaminated superfund site in southern Alabama, both during baseline (non-reactive capping) conditions and with the implementaion of reactive capping m...

Graphoepitaxy by encapsulation

DOEpatents

Geis, Michael W.; Smith, Henry I.; Antoniadis, Dimitri A.; Flanders, Dale C.

1986-01-01

Improvements on the graphoepitaxial process for obtaining epitaxial or preferred orientation films are described wherein a cap of material is formed over the film to be oriented, artificial surface-relief structure may be present in the substrate, the cap, or both, and the film may be heated by irradiation with electromagnetic radiation.

Effect of Tricalcium Aluminate on the Physicochemical Properties, Bioactivity, and Biocompatibility of Partially Stabilized Cements

PubMed Central

Chang, Kai-Chun; Chang, Chia-Chieh; Huang, Ying-Chieh; Chen, Min-Hua; Lin, Feng-Huei; Lin, Chun-Pin

2014-01-01

Background/Purpose Mineral Trioxide Aggregate (MTA) was widely used as a root-end filling material and for vital pulp therapy. A significant disadvantage to MTA is the prolonged setting time has limited the application in endodontic treatments. This study examined the physicochemical properties and biological performance of novel partially stabilized cements (PSCs) prepared to address some of the drawbacks of MTA, without causing any change in biological properties. PSC has a great potential as the vital pulp therapy material in dentistry. Methods This study examined three experimental groups consisting of samples that were fabricated using sol-gel processes in C3S/C3A molar ratios of 9/1, 7/3, and 5/5 (denoted as PSC-91, PSC-73, and PSC-55, respectively). The comparison group consisted of MTA samples. The setting times, pH variation, compressive strength, morphology, and phase composition of hydration products and ex vivo bioactivity were evaluated. Moreover, biocompatibility was assessed by using lactate dehydrogenase to determine the cytotoxicity and a cell proliferation (WST-1) assay kit to determine cell viability. Mineralization was evaluated using Alizarin Red S staining. Results Crystalline phases, which were determined using X-ray diffraction analysis, confirmed that the C3A contents of the material powder differed. The initial setting times of PSC-73 and PSC-55 ranged between 15 and 25 min; these values are significantly (p<0.05, ANOVA and post-hoc test) lower than those obtained for MTA (165 min) and PSC-91 (80.5 min). All of the PSCs exhibited ex vivo bioactivity when immersed in simulated body fluid. The biocompatibility results for all of the tested cements were as favorable as those of the negative control, except for PSC-55, which exhibited mild cytotoxicity. Conclusion PSC-91 is a favorable material for vital pulp therapy because it exhibits optimal compressive strength, a short setting time, and high biocompatibility and bioactivity. PMID:25247808

Characterization of measurement artefacts in fluoroptic temperature sensors: implications for laser thermal therapy at 810 nm.

PubMed

Davidson, Sean R H; Vitkin, I Alex; Sherar, Michael D; Whelan, William M

2005-04-01

Fluoroptic sensors are used to measure interstitial temperatures but their utility for monitoring laser interstitial thermal therapy (LITT) is unclear because these sensors exhibit a measurement artefact when exposed to the near-infrared (NIR) treatment light. This study investigates the cause of the artefact to determine whether fluoroptic sensors can provide reliable temperature measurements during LITT. The temperature rise measured by a fluoroptic sensor irradiated in non-absorbing media (air and water) was considered an artefact. Temperature rise was measured as a function of distance from a laser source. Two different sensor designs and several laser powers were investigated. A relationship between fluence rate and measurement artefact in water was determined and coupled with a numerical simulation of LITT in liver to estimate the error in temperature measurements made by fluoroptic sensors in tissue in proximity to the laser source. The effect of ambient light on the performance of sensors capped with a transparent material ("clear-capped sensors") was also investigated. The temperature rise recorded in air by both clear- and black-capped fluoroptic sensors decreased with distance from a laser source in a manner similar to fluence rate. Sensor cap material, laser power, and the thermal properties of the surrounding medium affected the magnitude of the artefact. Numerical simulations indicated that the accuracy of a clear-capped fluoroptic sensor used to monitor a typical LITT treatment in liver is > 1 degrees C provided the sensor is further than approximately 3 mm from the source. It was also shown that clear-capped fluoroptic sensors are affected by ambient light. The measurement artefact experienced by both black-capped and clear-capped fluoroptic sensors irradiated by NIR light scales with fluence rate and is due to direct absorption of the laser light, which results in sensor self-heating. Clear-capped fluoroptic sensors can be used to accurately monitor LITT in tissue but should be shielded from ambient light. Copyright 2005 Wiley-Liss, Inc.

Rigid polyurethane foam – kenaf core composites for structural applications

USDA-ARS?s Scientific Manuscript database

Kenaf (Hibiscus cannabinus L.) is a fast growing summer annual crop with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). The stalks of the kenaf plants contain two distinct fiber types, bast and core fibers. The...

Biorefinery process for production of paper and oligomers from Leucaena leucocephala K360 with or without prior autohydrolysis.

PubMed

Feria, M J; García, J C; Díaz, M J; Fernández, M; López, F

2012-12-01

Lignocellulosic material from Leucaena leucocephala was subjected to a two-stage fractionation process to obtain a valorized effluent containing hemicellulose derivatives and a solid phase for producing cellulose pulp by conventional soda-anthraquinone delignification. This solid phase allows the production of cellulose pulp, under less rigorous conditions from NaOH-AQ process (177 °C, 21%, 120 min) than without pretreatment delignification (185 °C, 25%, 150 min) and better or similar properties in the paper sheets obtained (yield 27.6 and 34.0%, brightness 39.3 and 31.6% ISO, tensile index 7.8 and 10.5 N m/g, burst index 0.43 and 0.29 MPa m(2)/kg with and without previous autohydrolysis) have be found. Also, the first autohydrolysis stage allows up to 46.6% of the initial hemicellulose in the raw material to be extracted as xylooligomers, xylose and furfural into the liquid phase. Copyright © 2012 Elsevier Ltd. All rights reserved.

Isolation and characterization of lignins from wheat straw: Application as binder in lithium batteries.

PubMed

Domínguez-Robles, Juan; Sánchez, Rafael; Díaz-Carrasco, Pilar; Espinosa, Eduardo; García-Domínguez, M T; Rodríguez, Alejandro

2017-11-01

Three different lignin-rich fractions have been used as binder material for electrodes in rechargeable lithium batteries. Lignin samples were obtained through three different pulping processes; kraft, soda and organosolv pulping processes, using wheat straw as raw material. Physico-chemical characterization of three types of lignins was evaluated. Characterization has been performed using Fourier transform infrared spectroscopy (FTIR) and 31 P NMR Spectroscopy to analyse the functional groups; gel permeation chromatography (GPC) for determining molar mass distribution (MWD), and thermogravimetric analysis (TGA) to follow the thermal behaviour. Electrodes containing lignin or poly vinylidene fluoride (PVDF) were tested electrochemically. The three different lignin samples exhibited excellent performance as binder, retaining the specific capacity after 50 cycles at a current density of 100mAg -1 . These results show that lignin could be used as a low-cost and environmental binder, replacing the PVDF polymer in electrodes for energy storage applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Avocado (Persea americana Mill.) phenolics, in vitro antioxidant and antimicrobial activities, and inhibition of lipid and protein oxidation in porcine patties.

PubMed

Rodríguez-Carpena, Javier-Germán; Morcuende, David; Andrade, María-Jesús; Kylli, Petri; Estévez, Mario

2011-05-25

The first aim of the present work (study 1) was to analyze ethyl acetate, 70% acetone, and 70% methanol extracts of the peel, pulp, and seed from two avocado (Persea americana Mill.) varieties, namely, 'Hass' and 'Fuerte', for their phenolic composition and their in vitro antioxidant activity using the CUPRAC, DPPH, and ABTS assays. Their antimicrobial potential was also studied. Peels and seeds had higher amounts of phenolics and a more intense in vitro antioxidant potential than the pulp. Peels and seeds were rich in catechins, procyanidins, and hydroxycinnamic acids, whereas the pulp was particularly rich in hydroxybenzoic and hydroxycinnamic acids and procyanidins. The total phenolic content and antioxidant potential of avocado phenolics was affected by the extracting solvent and avocado variety. The avocado materials also displayed moderate antimicrobial effects against Gram-positive bacteria. Taking a step forward (study 2), extracts (70% acetone) from avocado peels and seeds were tested as inhibitors of oxidative reactions in meat patties. Avocado extracts protected meat lipids and proteins against oxidation with the effect on lipids being dependent on the avocado variety.

Volatile-rich Crater Interior Deposits in the Polar Regions of Mars: Evidence for Ice Cap Advance and Retreat

NASA Technical Reports Server (NTRS)

Russell, Patrick S.; Head, James W.; Hecht, Michael H.

2003-01-01

Many craters on Mars are partially filled by distinctive material emplaced by post-impact processes. This crater fill material is an interior mound which is generally separated from the walls of the crater by a trough that may be continuous along the crater circumference (i.e. a ring-shaped trough), or which may only partially contact the crater walls (i.e. a crescent-shaped trough). The fill deposit is frequently offset from the crater center and may be asymmetric in plan view. Populations of such craters include those in the circum-south polar cap region, in Arabia Terra, associated with the Medusae Fossae Formation, and in the northern lowlands proximal to the north polar cap. We focus on those craters in circumpolar regions and assess their relationship to polar cap advance and retreat, especially the possibility that fill material represents remnants of a formerly larger contiguous cap. Volatile-rich deposits have the property of being modifiable by the local stability of the solid volatile, which is governed by local energy balance. Here we test the hypothesis that asymmetries in volatile fill shape, profile, and center-location within a crater result from asymmetries in local energy balance within the crater, due mainly to variation of solar insolation and radiative effects of the crater walls over the crater interior. Model profiles of crater fill are compared with MOLA topographic profiles to assess this hypothesis. If asymmetry in morphology and location of crater fill are consistent with radiative-dominated asymmetries in energy budget within the crater, then 1) the volatile-rich composition of the fill is supported (this process should not be effective at shaping volcanic or sedimentary deposits), and 2) the dominant factor determining the observed shape of volatile-rich crater fill is the local radiative energy budget (and erosive processes such as eolian deflation are secondary or unnecessary). We also use a geographic and energy model approach to specifically test the idea that material in partially filled craters around the south pole may once have been contiguous to the cap and may have been sustained and modified by radiative processes specific to the crater environment (as opposed to the surrounding plains) as the cap retreated.

The anaerobic digestion of pig carcase with or without sugar beet pulp, as a novel on-farm disposal method.

PubMed

Kirby, Marie E; Theodorou, Michael K; Brizuela, Carole M; Huntington, James A; Powles, Jayne; Wilkinson, Robert G

2018-05-01

Anaerobic digestion was investigated as a potential method for on-farm disposal of fallen stock (pig carcases), degrading the carcase material to produce biogas and digestate. The effects of feedstock (sugar beet pulp or pig carcase material or a 50:50 mix) and organic loading rate (50 g-TS L -1 or 100 g-TS L -1 ), during mesophilic (35 °C) anaerobic digestion were investigated. Anaerobic digestion was achieved for all experimental treatments, however the pig carcase material at the higher organic loading rate produced the second highest methane yield (0.56 Nm 3 kg-VS -1 versus a range of 0.14-0.58 Nm 3 kg-VS -1 for other treatments), with the highest percentage of methane in total biogas (61.6% versus a range of 36.1-55.2% for all other treatments). Satisfactory pathogen reduction is a legislative requirement for disposal of carcase material. Pathogens were quantified throughout the anaerobic digestion process. Enterococcus faecalis concentrations decreased to negligible levels (2.8 log 10 CFU g-TS -1 ), whilst Clostridium perfringens levels remained unaffected by treatment throughout the digestion process (5.3 ± 0.2 log 10 CFU g-TS -1 ). Copyright © 2018 Elsevier Ltd. All rights reserved.

In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites.

PubMed

Baroudi, Kusai; Silikas, Nick; Watts, David C

2009-01-01

The aim of this study was to investigate the pulpal temperature rise induced during the polymerization of flowable and non-flowable composites using light-emitting diode (LED) and halogen (quartz-tungsten-halogen) light-curing units (LCUs). Five flowable and three non-flowable composites were examined. Pulpal temperature changes were recorded over 10 min in a sample primary tooth by a thermocouple. A conventional quartz-tungsten-halogen source and two LEDs, one of which was programmable, were used for light curing the resin composites. Three repetitions per material were made for each LCU. There was a wide range of temperature rises among the materials (P < 0.05). Temperature rises ranged between 1.3 degrees C for Filtek Supreme irradiated by low-power LED and 4.5 degrees C for Grandio Flow irradiated by high-power LED. The highest temperature rises were observed with both the LED high-power and soft-start LCUs. The time to reach the exothermic peak varied significantly between the materials (P < 0.05). Pulpal temperature rise is related to both the radiant energy output from LCUs and the polymerization exotherm of resin composites. A greater potential risk for heat-induced pulp damage might be associated with high-power LED sources. Flowable composites exhibited higher temperature rises than non-flowable materials, because of higher resin contents.

Effect of plantation density on kraft pulp production from red pine (Pinus resinosa Ait.)

Treesearch

J.Y. Zhu; G.C. Myers

2006-01-01

Red pine (Pinus resinosa Ait.) butt logs from 38 year old research plots were used to study the effect of plantation stand density on kraft pulp production. Results indicate that plantation stand density can affect pulp yield, unrefined pulp mean fibre length, and the response of pulp fibre length to pulp refining. However, the effect of plantation stand density on...

Graphoepitaxy by encapsulation

DOEpatents

Geis, M.W.; Smith, H.I.; Antoniadis, D.A.; Flanders, D.C.

1986-01-21

Improvements on the graphoepitaxial process for obtaining epitaxial or preferred orientation films are described wherein a cap of material is formed over the film to be oriented, artificial surface-relief structure may be present in the substrate, the cap, or both, and the film may be heated by irradiation with electromagnetic radiation. 13 figs.

Advising. CAP Job Function.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

This Job Function Book (Advising) is one of the 14 components (see note) of the Career Alert Planning (CAP) program, a set of individualized materials designed to help participants find out about themselves and about the kind of work for which they are suited. In this program, participants become acquainted with occupations that are representative…

DEMONSTRATION OF THE AQUABLOK® SEDIMENT CAPPING TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

AquaBlok^® is an innovative, proprietary clay polymer composite developed by AquaBlok, Ltd. of Toledo, OH, and represents an alternative to traditional sediment capping materials such as sand. It is designed to swell and form a continuous and highly impermeable isolatio...

The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography

PubMed Central

2012-01-01

Background Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. Results Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth ≤5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth ≤5 years. A segmented pulp system was found in 72% of the investigated teeth. Segmentation into separate mesial and distal pulp compartments was most commonly present. Pulp horn 4 coalesced either with the mesial pulp horns 1 and 3 or with the distal pulp horns 2 and 5. Conclusions Details of the pulpar anatomy of equine cheek teeth are provided, supporting the continuous advancement in endodontic therapy. Numerous individual configurations of the pulp system were obtained in maxillary cheek teeth, but much less variability was seen in mandibular cheek teeth. PMID:23006500

Osteogenesis and angiogenesis properties of dental pulp cell on novel injectable tricalcium phosphate cement by silica doped.

PubMed

Su, Ying-Fang; Lin, Chi-Chang; Huang, Tsui-Hsien; Chou, Ming-Yung; Yang, Jaw-Ji; Shie, Ming-You

2014-09-01

β-Tricalcium phosphate (β-TCP) is an osteoconductive material in clinical. In this study, we have doped silica (Si) into β-TCP and enhanced its bioactive and osteostimulative properties. To check its effectiveness, a series of Si-doped with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of the diametral tensile strength, ions released and weight loss of cements was considered after immersion. In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on Si-doped β-TCP cements. The results showed that setting time and injectability of the Si-doped β-TCP cements were decreased as the Si content was increased. At the end of the immersion point, weight losses of 30.1%, 36.9%, 48.1%, and 55.3% were observed for the cement doping 0%, 10%, 20%, and 30% Si into β-TCP cements, respectively. In vitro cell experiments show that the Si-rich cements promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the Si-doped in the cement is more than 20%, the amount of cells and osteogenesis protein of hDPCs was stimulated by Si released from Si-doped β-TCP cements. The degradation of β-TCP and osteogenesis of Si gives a strong reason to believe that these Si-doped β-TCP cements may prove to be promising bone repair materials. Copyright © 2014 Elsevier B.V. All rights reserved.

JACKETED URANIUM SLUG

DOEpatents

Ohlinger, L.A.; Cooper, C.M.

1958-10-01

Fuel elements for nuclear reactors are described. Eacb fuel element is comprised of a solid cylindrical slug containing fissionable material enclosed within a fluid tight jacket of neutron permeable material such as aluminum. The jacket is provided with a flexible end cap and with a sealing member having a substantially fluid-tight fit within the jacket in tight abutment with the end cap and the end of the slug. A fluid passage is provided between the end of the slug and the cap whereby leakage fiuid is principally directed to the end of the slug. In this manner, any reaction between the fissionable material and fiuid which may take place occurs more rapidly at the end of the slug than along the sides between the slug and the jacket, thereby causing longitudinal expansion of the fuel element prior to radial expansion. The longitudinal expansion can be readily detected and the fuel element removed from the coolant tube before radial expansion causes it to become jammed in the tube.

Simultaneous Decolorization and Biohydrogen Production from Xylose by Klebsiella oxytoca GS-4-08 in the Presence of Azo Dyes with Sulfonate and Carboxyl Groups

PubMed Central

Cao, Ming-yue; Wang, Peng-tao; Wang, Shi; Yue, Ying-rong; Yuan, Wen-duo; Qiao, Wei-chuan; Wang, Fei

2017-01-01

ABSTRACT Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture of Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter−1 of xylose as the substrate, a maximum xylose utilization rate (URxyl) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H2 mol of xylose−1, respectively, were obtained. Biohydrogen kinetics and electron equivalent (e− equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes. IMPORTANCE The pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such as lignin, whose reclamation is considered economically crucial and environmentally friendly. Furthermore, azo dyes are usually added in order to fabricate anticounterfeiting paper, which further increases the complexity of the pulp and paper wastewater. This work may offer a better understanding of biohydrogen production from xylose in the presence of azo dyes and provide a promising energy-recycling method for treating pulp and paper wastewater, especially for those containing azo dyes. PMID:28283518

Dental Pulp Testing: A Review

PubMed Central

Chen, Eugene; Abbott, Paul V.

2009-01-01

Dental pulp testing is a useful and essential diagnostic aid in endodontics. Pulp sensibility tests include thermal and electric tests, which extrapolate pulp health from sensory response. Whilst pulp sensibility tests are the most commonly used in clinical practice, they are not without limitations and shortcomings. Pulp vitality tests attempt to examine the presence of pulp blood flow, as this is viewed as a better measure of true health than sensibility. Laser Doppler flowmetry and pulse oximetry are examples of vitality tests. Whilst the prospect is promising, there are still many practical issues that need to be addressed before vitality tests can replace sensibility tests as the standard clinical pulp diagnostic test. With all pulp tests, the results need to be carefully interpreted and closely scrutinised as false results can lead to misdiagnosis which can then lead to incorrect, inappropriate, or unnecessary treatment. PMID:20339575

40 CFR 430.45 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Dissolving Sulfite Subcategory... dissolving sulfite pulp facilities where nitration grade pulp is produced] Pollutant or pollutant property Kg... dissolving sulfite pulp facilities where viscose grade pulp is produced] Pollutant or pollutant property Kg...

40 CFR 430.75 - New source performance standards (NSPS).

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Mechanical Pulp Subcategory § 430.75 New source performance standards (NSPS). (a) The following applies to mechanical pulp...-mechanical process; mechanical pulp facilities where the integrated production of pulp and coarse paper...

Ethanol determination in frozen fruit pulps: an application of quantitative nuclear magnetic resonance.

PubMed

da Silva Nunes, Wilian; de Oliveira, Caroline Silva; Alcantara, Glaucia Braz

2016-04-01

This study reports the chemical composition of five types of industrial frozen fruit pulps (acerola, cashew, grape, passion fruit and pineapple fruit pulps) and compares them with homemade pulps at two different stages of ripening. The fruit pulps were characterized by analyzing their metabolic profiles and determining their ethanol content using quantitative Nuclear Magnetic Resonance (qNMR). In addition, principal component analysis (PCA) was applied to extract more information from the NMR data. We detected ethanol in all industrial and homemade pulps; and acetic acid in cashew, grape and passion fruit industrial and homemade pulps. The ethanol content in some industrial pulps is above the level recommended by regulatory agencies and is near the levels of some post-ripened homemade pulps. This study demonstrates that qNMR can be used to rapidly detect ethanol content in frozen fruit pulps and food derivatives. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Production of colony-stimulating factor in human dental pulp fibroblasts.

PubMed

Sawa, Y; Horie, Y; Yamaoka, Y; Ebata, N; Kim, T; Yoshida, S

2003-02-01

Class II major histocompatilibity complex (MHC)-expressing cells are usually distributed in dental pulp, and it was postulated that the colony-stimulating factor (CSF) derived from dental pulp fibroblasts contributes to the migration of class II MHC-expressing cells into pulp tissue. This study aimed to investigate the CSF production of human dental pulp fibroblasts. In pulp tissue sections, granulocyte (G)-CSF was detected from normal teeth, while G-CSF, macrophage (M)-CSF, and granulocyte-macrophage (GM)-CSF were detected from teeth with dentinal caries. In cultured dental pulp fibroblasts, G-CSF was detected by immunostaining, immunoprecipitation, and ELISA, and mRNAs of G-CSF, M-CSF, and GM-CSF were detected by RT-PCR. The dental pulp fibroblasts cultured with TNF-alpha were found to increase the G-CSF expression and to produce M-CSF and GM-CSF. These findings suggest that dental pulp fibroblasts usually produce G-CSF. In the presence of TNF-alpha, dental pulp fibroblast express M-CSF and GM-CSF.

Crank shaft support assembly

DOEpatents

Natkin, Robert J.; Oltmans, Bret; Allison, John E.; Heater, Thomas J.; Hines, Joy Adair; Tappen, Grant K.; Peiskammer, Dietmar

2007-10-23

A crank shaft support assembly for increasing stiffness and reducing thermal mismatch distortion in a crank shaft bore of an engine comprising different materials. A cylinder block comprises a first material and at least two crank journal inserts are insert-molded into respective crank journal regions of the cylinder block and comprise a second material having greater stiffness and a lower thermal coefficient of expansion that the first material. At least two bearing caps are bolted to the respective crank journal inserts and define, along with the crank journal inserts, at least two crank shaft support rings defining a crank shaft bore coaxially aligned with a crank shaft axis. The bearing caps comprise a material having higher stiffness and a lower thermal coefficient of expansion than the first material and are supported on the respective crank journal inserts independently of any direct connection to the cylinder block.

Histopathologic changes in dental pulp of teeth with chronic periodontitis.

PubMed

Aguiar, Telma R; Tristao, Gilson C; Mandarino, Denize; Zarranz, Laila; Ferreira, Vinicius F; Barboza, Eliane P

2014-05-01

The aim of this study was to evaluate the histopathologic changes in dental pulp of teeth with chronic advanced periodontitis. In 22 patients, 30 teeth were selected for inclusion. Patients had received no periodontal treatment. No teeth had caries, abrasion, attrition, erosion, trauma, or restoration. Radiographically, all teeth showed bone-support destruction to the apex. Thermal and cavity tests were used to evaluate pulp vitality. After tooth extractions, crowns were separated from roots at the cementoenamel junction. Both the crowns and the roots were prepared for histopathologic analyses. Radicular pulp was analyzed considering both coronal and apical halves. In 100 percent of the cases, coronal pulp exhibited soft connective tissue. In the coronal half of radicular pulp, soft connective tissue was present in 60 percent of the cases, fibrosis in 30 percent, and fibrosis associated with dystrophic calcification in 10 percent. In the apical half of radicular pulp, 6.6 percent of the cases demonstrated fibrosis; 23 percent exhibited fibrosis associated with pulp atrophy and secondary dentin; and 63.3 percent showed fibrosis, pulp atrophy, secondary dentin, and diffuse calcification. Radicular pulp of teeth with chronic periodontitis presents characteristics compatible with pulp changes resulting from pulp aging. In such cases, endodontic treatment is not indicated to enhance periodontal treatment results.

Dental pulp neurophysiology: part 2. Current diagnostic tests to assess pulp vitality.

PubMed

Abd-Elmeguid, Ashraf; Yu, Donald C

2009-03-01

In this second part of our 2-part review, we discuss recent research about pulp tests that determine the vitality of the tooth and clinically accepted pulp testers. A pain response to hot, cold or an electric pulp tester indicates the vitality of only a tooth's pulpal sensory supply; the response does not give any idea about the state of the pulp. Although the sensitivity of these tests is high, when false-positive and false-negative results occur, they may affect the treatment of the tooth. A tooth falsely diagnosed as nonvital with an electric pulp tester may undergo an unnecessary root canal, whereas one falsely diagnosed as vital may be left untreated, causing the necrotic tissue to destroy the supporting tissues (resorption). The vascular supply is more important to the determination of the health of the pulp than the sensory supply. Pulp death is caused by cessation of blood flow and may result in a necrotic pulp, even though the pulpal sensory supply may still be viable. The pulp can be healed only if the circulating blood flow is healthy. Although still under investigation, diagnostic devices that examine pulpal blood flow, such as the pulse oximeter and laser Doppler flowmetry, show promising results for the assessment of pulp vitality.

Optically pumped lasing and electroluminescence of formamidinium perovskite semiconductors prepared by the cast-capping method

NASA Astrophysics Data System (ADS)

Sasaki, Fumio; Nguyen, Van-Cao; Yanagi, Hisao

2018-03-01

Optically pumped lasing and electroluminescence (EL) have been observed in solution-processed perovskite semiconducting materials of formamidinium lead bromide, CH(NH2)2PbBr3. Microcavities with flat surfaces and sharp edges have been easily obtained by the simple solution process called the “cast-capping method”. The crystals show clear multimode lasing of Fabry-Pérot cavities. The mode intervals are well explained by the optical constants with large dispersions of the materials. We have also fabricated EL devices and obtained clear EL in a single layer of the materials, but the EL intensity has been quenched rapidly.

Environmental performance of straw-based pulp making: A life cycle perspective.

PubMed

Sun, Mingxing; Wang, Yutao; Shi, Lei

2018-03-01

Agricultural straw-based pulp making plays a vital role in pulp and paper industry, especially in forest deficient countries such as China. However, the environmental performance of straw-based pulp has scarcely been studied. A life cycle assessment on wheat straw-based pulp making in China was conducted to fill of the gaps in comprehensive environmental assessments of agricultural straw-based pulp making. On average, the global warming potential (GWP), GWP excluding biogenic carbon, acidification potential and eutrophication potential of wheat straw based pulp making are 2299kg CO 2 -eq, 4550kg CO 2 -eq, 16.43kg SO 2 -eq and 2.56kg Phosphate-eq respectively. The dominant factors contributing to environmental impacts are coal consumption, electricity consumption, and chemical (NaOH, ClO 2 ) input. Chemical input decrease and energy recovery increase reduce the total environmental impacts dramatically. Compared with wood-based and recycled pulp making, wheat straw-based pulp making has higher environmental impacts, which are mainly due to higher energy and chemical requirements. However, the environmental impacts of wheat straw-based pulp making are lower than hemp and flax based pulp making from previous studies. It is also noteworthy that biogenic carbon emission is significant in bio industries. If carbon sequestration is taken into account in pulp making industry, wheat straw-based pulp making is a net emitter rather than a net absorber of carbon dioxide. Since wheat straw-based pulp making provides an alternative for agricultural residue management, its evaluation framework should be expanded to further reveal its environmental benefits. Copyright © 2017 Elsevier B.V. All rights reserved.

Chromophores in lignin-free cellulosic materials belong to three compound classes. Chromophores in cellulosics, XII

USDA-ARS?s Scientific Manuscript database

The CRI (chromophore release and identification) method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extrem...

Recycled Fiber Properties as Affected by Contaminants and Removal Processes.

DTIC Science & Technology

Five materials were applied to either a kraft pulp furnish or to a kraft paper and were removed by conventional removal processes. Uncontaminated... kraft paper subjected to the same removal processes determined that the process, not the contaminant, was responsible for changes in sheet properties

40 CFR 430.45 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Dissolving Sulfite... biocides: Subpart D [NSPS for dissolving sulfite pulp facilities where nitration grade pulp is produced... all times. Subpart D [NSPS for dissolving sulfite pulp facilities where viscose grade pulp is produced...

40 CFR 430.70 - Applicability; description of the mechanical pulp subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... mechanical pulp subcategory. 430.70 Section 430.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Mechanical Pulp Subcategory § 430.70 Applicability; description of the mechanical pulp subcategory. The... groundwood chemi-mechanical mills; the production of pulp and paper at groundwood mills through the...

SOME ASPECTS OF THE CHEMISTRY OF POLYSULFIDE PULPING,

DTIC Science & Technology

Kraft pulping with the addition of polysulfide, i.e. polysulfide pulping, is one of the few methods available which can be used to increase the yield...and change the properties of kraft pulp. The chemistry of aqueous polysulfide solutions and the concurrent reactions occurring in polysulfide pulping

Lead sorption-desorption from organic residues.

PubMed

Duarte Zaragoza, Victor M; Carrillo, Rogelio; Gutierrez Castorena, Carmen M

2011-01-01

Sorption and desorption are mechanisms involved in the reduction of metal mobility and bioavailability in organic materials. Metal release from substrates is controlled by desorption. The capacity of coffee husk and pulp residues, vermicompost and cow manure to adsorb Pb2+ was evaluated. The mechanisms involved in the sorption process were also studied. Organic materials retained high concentrations of lead (up to 36,000 mg L(-1)); however, the mechanisms of sorption varied according to the characteristics of each material: degree of decomposition, pH, cation exchange capacity and percentage of organic matter. Vermicompost and manure removed 98% of the Pb from solution. Lead precipitated in manure and vermicompost, forming lead oxide (PbO) and lead ferrite (PbFe4O7). Adsorption isotherms did not fit to the typical Freundlich and Langmuir equations. Not only specific and non-specific adsorption was observed, but also precipitation and coprecipitation. Lead desorption from vermicompost and cow manure was less than 2%. For remediation of Pb-polluted sites, the application of vermicompost and manure is recommended in places with alkaline soils because Pb precipitation can be induced, whereas coffee pulp residue is recommended for acidic soils where Pb is adsorbed.

Results and Outlook of The Aluminum Capture Experiment (AlCap)

NASA Astrophysics Data System (ADS)

Quirk, John R.; Miller, James; ALCap Collaboration Collaboration

2016-03-01

Observation of neutrinoless muon-to-electron conversion in the presence of a nucleus would be unambiguous evidence of physics Beyond the Standard Model. Two experiments, COMET at J-PARC and Mu2e at Fermilab, will search for this process in the coming decade. Barring discovery, these experiments will provide upper-limits on this branching ratio up to 10,000 times better than previously published. COMET/Mu2e developed a joint venture, the AlCap Experiment, to measure particle emission spectra from muonic interactions in a number of materials. As a major source of background hits in COMET/Mu2e detectors, AlCap sought to measure the charged particle and neutron spectra following nuclear capture on the candidate target materials aluminum and titanium. Additionally, COMET/Mu2e are exploring normalization schemes via AlCap's measurement of the photon spectra following both atomic and nuclear capture. Over the course of 2013 and 2015, AlCap performed three runs at the Paul Scherrer Institut in Switzerland. The first acquired preliminary data for all spectra, the second run collected only neutron and photon data, and the third primarily charged particle data. Preliminary analyses of the first two runs, already impactful for COMET/Mu2e, is presented along with a summary of the third.

40 CFR 430.73 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mechanical Pulp Subcategory § 430.73 Effluent limitations guidelines representing the degree of effluent...) The following applies to: mechanical pulp facilities where the integrated production of pulp and coarse paper, molded pulp products, and newsprint at groundwood mills occurs; and mechanical pulp...

Human dental pulp stem cells with highly angiogenic and neurogenic potential for possible use in pulp regeneration.

PubMed

Nakashima, Misako; Iohara, Koichiro; Sugiyama, Masahiko

2009-01-01

Dental caries is a common public health problem, causing early loss of dental pulp and resultant tooth loss. Dental pulp has important functions to sustain teeth providing nutrient and oxygen supply, innervation, reactionary/reparative dentin formation and immune response. Regeneration of pulp is an unmet need in endodontic therapy, and angiogenesis/vasculogenesis and neurogenesis are critical for pulp regeneration. Permanent and deciduous pulp tissue is easily available from teeth after extraction without ethical issues and has potential for clinical use. In this review, we introduce some stem cell subfractions, CD31(-)/CD146(-) SP cells and CD105(+) cells with high angiogenic and neurogenic potential, derived from human adult dental pulp tissue. Potential utility of these cells is addressed as a source of cells for treatment of cerebral and limb ischemia and pulp inflammation complete with angiogenesis and vasculogenesis.

Pulp and apical tissue response to deep caries in immature teeth: A histologic and histobacteriologic study.

PubMed

Ricucci, Domenico; Siqueira, José F; Loghin, Simona; Lin, Louis M

2017-01-01

Descriptions of the pathologic changes in the pulp and associated apical structures of human immature teeth in response to deep caries are lacking in the literature. This article describes the histologic events associated with the radicular pulp and the apical tissues of human immature teeth following pulp inflammation and necrosis. Twelve immature teeth with destructive caries lesions were obtained from 8 patients. Two intact immature teeth served as controls. Teeth were extracted for reasons not related to this study and immediately processed for histopathologic and histobacteriologic analyses. Serial sections were examined for the pulp conditions and classified as reversible or irreversible pulp inflammation, or pulp necrosis. Other histologic parameters were also evaluated. In the 3 cases with reversible pulp inflammation, tissue in the pulp chamber showed mild to moderate inflammation and tertiary dentin formation related to tubules involved in the caries process. Overall, the radicular pulp tissue, apical papilla and Hertwig's epithelial root sheath (HERS) exhibited characteristics of normality. In the 3 cases with irreversible pulp inflammation, the pulps were exposed and severe inflammation occurred in the pulp chamber, with minor areas of necrosis and infection. Large areas of the canal walls were free from odontoblasts and lined by an atubular mineralized tissue. The apical papilla showed extremely reduced cellularity or lack of cells and HERS was discontinuous or absent. In the 6 cases with pulp necrosis, the coronal and radicular pulp tissue was necrotic and colonized by bacterial biofilms. The apical papilla could not be discerned, except for one case. HERS was absent in the necrotic cases. While immature teeth with reversible pulpitis showed histologic features almost similar to normal teeth in the canal and in the apical region, those with irreversible pulpitis and necrosis exhibited significant alterations not only in the radicular pulp but also in the apical tissues, including the apical papilla and HERS. Alterations in the radicular pulp and apical tissues help explain the outcome of current regenerative/reparative therapies and should be taken into account when devising more predictable therapeutic protocols for teeth with incomplete root formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Materials Data on CaP2Xe5F22 (SG:33) by Materials Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristin Persson

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Materials Data on K3CaP2HO8 (SG:12) by Materials Project

DOE Data Explorer

Kristin Persson

2014-07-09

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Materials Data on CaP2(H2O3)3 (SG:2) by Materials Project

DOE Data Explorer

Kristin Persson

2014-07-09

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Materials Data on CaP3H10NO12 (SG:18) by Materials Project

DOE Data Explorer

Kristin Persson

2014-07-09

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Effect of capping layer on interlayer coupling in synthetic spin valves

NASA Astrophysics Data System (ADS)

Li, Kebin; Qiu, Jinjun; Han, Guchang; Guo, Zaibing; Zheng, Yuankai; Wu, Yihong; Li, Jinshan

2005-01-01

The magnetic and transport properties of high quality synthetic spin-valves with the structure of Ta/NiFe/IrMn/CoFe/Ru/CoFe/NOL/CoFe/Cu/CoFe/CL were studied by using magnetoresistance measurements. Here Ti, Hf, and Al are used as the capping layer. It is found that both the thickness and materials properties of the capping layers can affect the interlayer coupling field. The interlayer coupling field oscillates weakly with respect to the thickness of the Ti and Hf capping layers. Extremely strong ferromagnetic coupling has been observed when the thickness of the Al capping layer is in a certain range where resonant exchange coupling takes place. The strength of the interlayer coupling is inversely proportional to the square of the thickness of the spacer. It is a typical characteristic of quantum size effect.

Biologic Potential of Calcium Phosphate Biopowders Produced via Decomposition Combustion Synthesis

PubMed Central

Vollmer, N.; King, K.B.; Ayers, R.

2015-01-01

The aim of this research was to evaluate the biologic potential of calcium phosphate (CaP) biopowders produced with a novel reaction synthesis system. Decomposition combustion synthesis (DCS) is a modified combustion synthesis method capable of producing CaP powders for use in bone tissue engineering applications. During DCS, the stoichiometric ratio of reactant salt to fuel was adjusted to alter product chemistry and morphology. In vitro testing methods were utilized to determine the effects of controlling product composition on cytotoxicity, proliferation, biocompatibility and biomineralization. In vitro, human fetal osteoblasts (ATCC, CRL-11372) cultured with CaP powder displayed a flattened morphology, and uniformly encompassed the CaP particulates. Matrix vesicles containing calcium and phosphorous budded from the osteoblast cells. CaP powders produced via DCS are a source of biologically active, synthetic, bone graft substitute materials PMID:26034341

Assessment of oxygen saturation in dental pulp of permanent teeth with periodontal disease.

PubMed

Giovanella, Larissa Bergesch; Barletta, Fernando Branco; Felippe, Wilson Tadeu; Bruno, Kely Firmino; de Alencar, Ana Helena Gonçalves; Estrela, Carlos

2014-12-01

In individuals with periodontal disease, dental pulp status should be determined before a treatment plan is made. Pulse oximeters are promising diagnostic tools to evaluate pulp vascularization. This study used pulse oximetry to determine the level of oxygen saturation in dental pulp of intact permanent teeth with periodontal attachment loss (PAL) and gingival recession (GR) and to evaluate the correlation between periodontal disease and level of oxygen saturation in the pulp. This study included 67 anterior teeth of 35 patients; all teeth showed intact crowns, PAL, a periodontal pocket (PP), and GR. The teeth underwent periodontal examination, cold and electric pulp testing, and pulse oximetry measurements. The Pearson correlation coefficient and a linear regression coefficient were calculated to evaluate the degree of correlation between periodontal disease markers (PAL, PP, and GR) and the level of oxygen saturation in dental pulp. These tests also evaluated possible associations between oxygen saturation and cold and electric pulp testing. PAL, PP, and GR had negative correlations with oxygen saturation in dental pulp. Conversely, no statistically significant association was found between oxygen saturation in dental pulp and the response to electric sensibility testing. Oxygen saturation was lower in the pulp of permanent teeth with PAL, PP, and GR, indicating that periodontal disease correlates with the level of oxygen saturation in the pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Uremia Induces Dental Pulp Ossification but Reciprocally Inhibits Adjacent Alveolar Bone Osteogenesis.

PubMed

Yang, Chih-Yu; Chang, Zee-Fen; Chau, Yat-Pang; Chen, Ann; Lee, Oscar Kuang-Sheng; Yang, An-Hang

2015-11-01

Uremic patients are predisposed to atrophy of the alveolar bone and narrowing of the dental pulp chamber. Such pulp chamber changes have only been diagnosed radiologically; however, this has not been supported by any pathological evidence. We used a uremic rat model with secondary hyperparathyroidism induced by 5/6 nephrectomy surgery and high-phosphate diet to examine the dental pulp and adjacent alveolar bone pathology. In addition, we collected pulp tissues for real-time PCR. We found an opposite histopathological presentation of the ossified dental pulp and the osteomalacic adjacent alveolar bone. Furthermore, pulp cells with positive staining for Thy-1, a surrogate stem cell marker, were significantly reduced in the pulp of uremic rats compared to the controls, indicating a paucity of stem cells. This was further evidenced by the reduced pulp expression of dickkopf-1 (Dkk-1), a Wnt/β-catenin signaling inhibitor produced by mesenchymal stem cells. In contrast, expressions of receptor activator of nuclear factor κB ligand (RANKL) and RANK in uremic pulp were up-regulated, probably to counteract the ossifying process of uremic pulp. In conclusion, uremic pulp ossifications were associated with a paucity of stem cells and dysregulated Dkk-1 and RANKL signaling systems, further shifting the imbalance toward osteogenesis. Strategies to counteract such an imbalance may offer a potential therapeutic target to improve dental health in uremic patients, which warrants further interventional studies.

KSC-03PD-2981

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. In the Orbiter Processing Facility, packing material is placed over the nose cap that was removed from Atlantis. The reinforced carbon-carbon (RCC) nose cap is being sent to the original manufacturing company, Vought in Ft. Worth, Texas, a subsidiary of Lockheed Martin, to undergo non- destructive testing such as CAT scan and thermography.

Calcium phosphate-titanium composites for articulating surfaces of load-bearing implants.

PubMed

Bandyopadhyay, Amit; Dittrick, Stanley; Gualtieri, Thomas; Wu, Jeffrey; Bose, Susmita

2016-04-01

Calcium phosphate (CaP)-titanium (Ti) composites were processed using a commercial laser engineered net shaping (LENS™) machine to increase wear resistance of articulating surfaces of load-bearing implants. Such composites could be used to cover the surface of titanium implants and potentially increase the lifetime of a joint replacement. It was hypothesized that adding calcium phosphate to commercially pure titanium (CP-Ti) and Ti6Al4V alloy via laser processing would decrease the material loss when subjected to wear. This added protection would be due to the in situ formation of a CaP tribofilm. Different amounts of CaP were mixed by weight with pure Ti and Ti6Al4V powders. The mixed powders were then made into cylindrical samples using a commercial LENS™-750 system. Microstructures were observed and it was found the CaP had integrated into the titanium metal matrix. Compression test revealed that CaP significantly increased the 0.2% offset yield strength as well as the ultimate compressive strength of CP-Ti. It was found that the addition of CaP to pure titanium reduced the material loss and increased wear resistance. This was due to the formation of CaP tribofilm on the articulating surface. The in situ formed tribofilm also lowered the coefficient of friction and acted as a solid lubricant between the two interacting metal surfaces. Overall, CaP addition to Ti and its alloy Ti6Al4V show an effective way to minimize wear induced damage due to the formation of in situ tribofilm at the articulating surface, a strategy that can be utilized in various biomedical devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accuracy verification and identification of matrix effects. The College of American Pathologists' Protocol.

PubMed

Eckfeldt, J H; Copeland, K R

1993-04-01

Proficiency testing using stabilized control materials has been used for decades as a means of monitoring and improving performance in the clinical laboratory. Often, the commonly used proficiency testing materials exhibit "matrix effects" that cause them to behave differently from fresh human specimens in certain clinical analytic systems. Because proficiency testing is the primary method in which regulatory agencies have chosen to evaluate clinical laboratory performance, the College of American Pathologists (CAP) has proposed guidelines for investigating the influence of matrix effects on their Survey results. The purpose of this investigation was to determine the feasibility, usefulness, and potential problems associated with this CAP Matrix Effect Analytical Protocol, in which fresh patient specimens and CAP proficiency specimens are analyzed simultaneously by a field method and a definitive, reference, or other comparative method. The optimal outcome would be that both the fresh human and CAP Survey specimens agree closely with the comparative method result. However, this was not always the case. Using several different analytic configurations, we were able to demonstrate matrix and calibration biases for several of the analytes investigated.

Novel bleaching of thermomechanical pulp for improved paper properties

Treesearch

Marguerite S. Sykes; John H. Klungness; Freya Tan

2002-01-01

Production of mechanical pulp is expected to increase significantly to meet the growing global demand for paper. Mechanical pulping uses wood resources more efficiently with less negative impact on the environment than does chemical pulping. However, several problems related to mechanical pulping need to be resolved: high energy consumption, low paper strength...

40 CFR 430.72 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mechanical Pulp Subcategory § 430.72 Effluent limitations representing the degree of effluent reduction... limitations for mechanical pulp facilities where pulp and paper at groundwood chemi-mechanical mills are... times. Subpart G [BPT effluent limitations for mechanical pulp facilities where pulp and paper at...

Potential uses for peroxymonosulfate in pulping and bleaching

Treesearch

Edward L. Springer

1992-01-01

Practical and cost-effective uses for peroxymonosulfate can be developed in pulping and bleaching. Peroxymonosulfate pulping produces strong pulps, has lower capital requirements, and is less environmentally troublesome compared with current pulping processes. The cost of oxidant may, however, be somewhat too high for practical use. We discuss means for reducing the...

40 CFR 430.80 - Applicability; description of the non-wood chemical pulp subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-wood chemical pulp subcategory. 430.80 Section 430.80 Protection of Environment ENVIRONMENTAL... CATEGORY Non-Wood Chemical Pulp Subcategory § 430.80 Applicability; description of the non-wood chemical... production of pulp and paper at non-wood chemical pulp mills. This subcategory includes, but is not limited...

40 CFR 430.80 - Applicability; description of the non-wood chemical pulp subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-wood chemical pulp subcategory. 430.80 Section 430.80 Protection of Environment ENVIRONMENTAL... CATEGORY Non-Wood Chemical Pulp Subcategory § 430.80 Applicability; description of the non-wood chemical... production of pulp and paper at non-wood chemical pulp mills. This subcategory includes, but is not limited...

High pH-Sensitive TRPA1 Activation in Odontoblasts Regulates Mineralization.

PubMed

Kimura, M; Sase, T; Higashikawa, A; Sato, M; Sato, T; Tazaki, M; Shibukawa, Y

2016-08-01

Calcium hydroxide and mineral trioxide aggregate are widely used for indirect and direct pulp capping and root canal filling. Their dissociation into Ca(2+) and OH(-) in dental pulp creates an alkaline environment, which activates reparative/reactionary dentinogenesis. However, the mechanisms by which odontoblasts detect the pH of the extracellular environment remain unclear. We examined the alkali-sensitive intracellular Ca(2+) signaling pathway in rat odontoblasts. In the presence or absence of extracellular Ca(2+), application of alkaline solution increased intracellular Ca(2+) concentration, or [Ca(2+)]i Alkaline solution-induced [Ca(2+)]i increases depended on extracellular pH (8.5 to 10.5) in both the absence and the presence of extracellular Ca(2+) The amplitude was smaller in the absence than in the presence of extracellular Ca(2+) Each increase in [Ca(2+)]i, activated by pH 7.5, 8.5, or 9.5, depended on extracellular Ca(2+) concentration; the equilibrium binding constant for extracellular Ca(2+) concentration decreased as extracellular pH increased (1.04 mM at pH 7.5 to 0.11 mM at pH 9.5). Repeated applications of alkaline solution did not have a desensitizing effect on alkali-induced [Ca(2+)]i increases and inward currents. In the presence of extracellular Ca(2+), alkaline solution-induced [Ca(2+)]i increases were suppressed by application of an antagonist of transient receptor potential ankyrin subfamily member 1 (TRPA1) channels. Ca(2+) exclusion efficiency during alkaline solution-induced [Ca(2+)]i increases was reduced by a Na(+)-Ca(2+) exchanger antagonist. Alizarin red and von Kossa staining revealed increased mineralization levels under repeated high pH stimulation, whereas the TRPA1 antagonist strongly reduced this effect. These findings indicate that alkaline stimuli-such as the alkaline environment inside dental pulp treated with calcium hydroxide or mineral trioxide aggregate-activate Ca(2+) mobilization via Ca(2+) influx mediated by TRPA1 channels and intracellular Ca(2+) release in odontoblasts. High pH-sensing mechanisms in odontoblasts are important for activating dentinogenesis induced by an alkaline environment. © International & American Associations for Dental Research 2016.

COLLAPSED ABNORMAL POLLEN1 Gene Encoding the Arabinokinase-Like Protein Is Involved in Pollen Development in Rice1[C][W][OA

PubMed Central

Ueda, Kenji; Yoshimura, Fumiaki; Miyao, Akio; Hirochika, Hirohiko; Nonomura, Ken-Ichi; Wabiko, Hiroetsu

2013-01-01

We isolated a pollen-defective mutant, collapsed abnormal pollen1 (cap1), from Tos17 insertional mutant lines of rice (Oryza sativa). The cap1 heterozygous plant produced equal numbers of normal and collapsed abnormal grains. The abnormal pollen grains lacked almost all cytoplasmic materials, nuclei, and intine cell walls and did not germinate. Genetic analysis of crosses revealed that the cap1 mutation did not affect female reproduction or vegetative growth. CAP1 encodes a protein consisting of 996 amino acids that showed high similarity to Arabidopsis (Arabidopsis thaliana) l-arabinokinase, which catalyzes the conversion of l-arabinose to l-arabinose 1-phosphate. A wild-type genomic DNA segment containing CAP1 restored mutants to normal pollen grains. During rice pollen development, CAP1 was preferentially expressed in anthers at the bicellular pollen stage, and the effects of the cap1 mutation were mainly detected at this stage. Based on the metabolic pathway of l-arabinose, cap1 pollen phenotype may have been caused by toxic accumulation of l-arabinose or by inhibition of cell wall metabolism due to the lack of UDP-l-arabinose derived from l-arabinose 1-phosphate. The expression pattern of CAP1 was very similar to that of another Arabidopsis homolog that showed 71% amino acid identity with CAP1. Our results suggested that CAP1 and related genes are critical for pollen development in both monocotyledonous and dicotyledonous plants. PMID:23629836

A Histopathological Comparison of Pulpal Response to Chitra-CPC and Formocresol used as Pulpotomy Agents in Primary Teeth: A Clinical Trial

PubMed Central

Thomas, Bijimol

2012-01-01

ABSTRACT Preventive measures have helped to minimize the occurrence of dental caries. However, premature loss of primary teeth on account of dental caries still remains a common problem among children. The pulpotomy technique has been the choice for treating vital primary and young permanent teeth with carious, mechanical and traumatic pulp exposures. The ideal pulpotomy medicament should be bioinductive or at least biocompatible, bactericidal and harmless to the pulp and surrounding structures. It should also promote healing of the radicular pulp and prevent bacterial microleakage with the least interference in the physiological process of root resorption. Since the best criteria for judging the effectiveness of a medicament when used for vital pulp therapy is the response that it produces in the pulp. The purpose of the present study was to evaluate and compare the response of human pulp tissue to recently developed Indian material, Sree Chitra-Calcium Phosphate Cement (Chitra-CPC) and formocresol, used as pulpotomy agent in deciduous teeth. Chitra-CPC has been compared with formocresol, taking into account that formocresol is still considered the gold standard in primary tooth pulpotomy. The study was conducted among 10 children in the age group of 8 to 12 years focusing on 20 noncarious primary canines indicated for serial extraction. Each patient received two different pulpotomy procedures—one in each of the primary canines using formocresol and the other with Chitra-CPC as pulpotomy agents. After 70 days, the teeth were extracted and subjected to histological examination. The results did not reveal statistically significant difference between the two groups. But Chitra-CPC gave more favorable results, in respect of pulpal inflammation, dentin bridge formation, quality of dentin bridge and connective tissue in dentin bridge. How to cite this article: Ratnakumari N, Thomas B. A Histopathological Comparison of Pulpal Response to Chitra- CPC and Formocresol used as Pulpotomy Agents in Primary Teeth: A Clinical Trial. Int J Clin Pediatr Dent 2012;5(1):6-13. PMID:25206127

Relationship between lignin structure and delignification degree in Pinus pinaster kraft pulps.

PubMed

Baptista, C; Robert, D; Duarte, A P

2008-05-01

This study examines the structure of residual and dissolved lignins from Pinus pinaster pulps obtained at different degrees of delignification by laboratory conventional kraft pulping. The cooking H factor was varied from 85 to 8049. The residual and dissolved lignin samples were characterised by elemental analysis, residual carbohydrate content, permanganate oxidation and 13C NMR spectroscopy. The reflectance factor of the pulps was also determined in order to tentatively correlate the delignification degree and residual lignin structure with the pulp colour. The obtained results confirmed that the delignification degree increases the condensation of the lignin structure, which might have an influence upon the observed increased pulp colour. The lack of selectivity of kraft pulping process in the case of more delignified pulps was also shown.

Space fabrication: Graphite composite truss welding and cap forming subsystems

NASA Technical Reports Server (NTRS)

Jenkins, L. M.; Browning, D. L.

1980-01-01

An automated beam builder for the fabrication of space structures is described. The beam builder forms a triangular truss 1.3 meters on a side. Flat strips of preconsolidated graphite fiber fabric in a polysulfone matrix are coiled in a storage canister. Heaters raise the material to forming temperature then the structural cap section is formed by a series of rollers. After cooling, cross members and diagonal tension cords are ultrasonically welded in place to complete the truss. The stability of fabricated structures and composite materials is also examined.

Analysis of the rate of maturogenesis of a traumatized Cvek's stage 3 anterior tooth treated with platelet-rich fibrin as a regenerative tool using three-dimensional cone-beam computed tomography: an original case report.

PubMed

Solomon, Raji Viola; Faizuddin, Umrana; Guniganti, Sushma Shravani; Waghray, Shefali

2015-01-01

Regenerative endodontic procedures are biologically based procedures which deal with the regeneration of pulp-like tissue, more idealistically the pulp-dentin complex. The regeneration of this pulp-dentin complex in an infected necrotic tooth with an open apex is possible only when the canal is effectively disinfected. Though there are various procedures for treating open apex ranging from Ca(OH) 2 apexification, mineral trioxide aggregate apexification and surgical approach, regeneration of tissues has always taken superior hand over the repair of tissues. The mechanics behind the regenerative endodontic procedures is that despite the tooth being necrotic, some pulp tissue can survive apically which under favorable conditions proliferate to aid in the process of regeneration. In the past 2 decades, an increased understanding of the physiological roles of platelets in wound healing and after tissue injury has led to the idea of using platelets as therapeutic tools in the field regenerative endodontics. In the present case report with an open apex, high sterilization protocol is followed using triple antibiotic paste as intra-canal medicament, followed which platelet rich fibrin is used as the regenerative material of choice. Over an 18-month follow-up period, clinically patient is asymptomatic and radiographically there is complete regression of the periapical lesion and initiation of the root end closure.

Immunohistochemical study of dental pulp applied with 4-META/MMA-TBB adhesive resin after pulpotomy.

PubMed

Nakamura, M; Inoue, T; Shimono, M

2000-08-01

The purpose of this study was to investigate nerve regeneration and proliferative activity in amputated pulp tissue after the application of 4-META/MMA-TBB adhesive resin (4-META resin). Calcium hydroxide was used as a control material. At 3 days, fibroblast-like cells were positive for proliferating cell nuclear antigen (PCNA) in both 4-META resin- and calcium hydroxide-treated groups and were located mainly within 0.5 mm from the cut surface. Only a few fragmented neurofilament protein (NFP)-positive nerve fibers were observed in this area. At 7 and 14 days, the number of PCNA-positive cells had gradually decreased and regenerated NFP-positive nerve fibers were observed close to the cut surface of the pulp in both groups. At 21 days in the experimental group, several PCNA-positive cells were still found in the area 0.5 mm from the cut surface, and NFP-positive nerve fibers were detected about 0.15-;0.2 mm from the cut surface. In contrast, a dentin bridge was produced under the necrotic layer at 21 days in the control group. PCNA-positive cells were not found underneath the dentin bridge, but NFP-positive nerve fibers had regenerated close to it. These results suggest that although cell differentiation and nerve regeneration are delayed, wound healing occurred even after the application of 4-META resin to exposed pulp surface the same as calcium hydroxide application. Copyright 2000 John Wiley & Sons, Inc.

Biobleaching of wheat straw-rich soda pulp with alkalophilic laccase from gamma-proteobacterium JB: optimization of process parameters using response surface methodology.

PubMed

Singh, Gursharan; Ahuja, Naveen; Batish, Mona; Capalash, Neena; Sharma, Prince

2008-11-01

An alkalophilic laccase from gamma-proteobacterium JB was applied to wheat straw-rich soda pulp to check its bleaching potential by using response surface methodology based on central composite design. The design was employed by selecting laccase units, ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) concentration and pH as model factors. The results of second order factorial design experiments showed that all three independent variables had significant effect on brightness and kappa number of laccase-treated pulp. Optimum conditions for biobleaching of pulp with laccase preparation (specific activity, 65 nkat mg(-1) protein) were 20 nkat g(-1) of pulp, 2mM ABTS and pH 8.0 which enhanced brightness by 5.89% and reduced kappa number by 21.1% within 4h of incubation at 55 degrees C, without further alkaline extraction of pulp. Tear index (8%) and burst index (18%) also improved for laccase-treated pulp as compared to control raw pulp. Treatment of chemically (CEH1H2) bleached pulp with laccase showed significant effect on release of chromophores, hydrophobic and reducing compounds. Laccase-prebleaching of raw pulp reduced the use of hypochlorite by 10% to achieve brightness of resultant hand sheets similar to the fully chemically bleached pulp.

78 FR 47205 - National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-05

... material, isolation and capping of non- hazardous materials, installation of fencing, posting of warning... on the site, No excavations causing erosion, No excavation below base material of the road bed (State...

Triton Southern Hemisphere

NASA Image and Video Library

1998-06-08

This polar projection from NASA Voyager 2 of Triton southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds. http://photojournal.jpl.nasa.gov/catalog/PIA00423

Chemical approach for controlling nadimide cure temperature and rate

NASA Technical Reports Server (NTRS)

Lauver, R. W. (Inventor)

1984-01-01

Polyimide resins suitable for use as composite matrix materials are formed by copolymerization of maleic and norbornenyl endcapped monomers and oligomers. The copolymers can be cured at temperatures under about 300 C by controlling the available concentration of the maleic capped reactant. This control can be achieved by adding sufficient amounts of said maleic reactant, or by chemical modification of either copolymer, so as to either increase Diels-Alder retrogression of the norbornenyl capped reactant and/or holding initiation and polymerization to a rate compatible with the availability of the maleic capped reactant.

21 CFR 872.1720 - Pulp tester.

Code of Federal Regulations, 2011 CFR

2011-04-01

... DENTAL DEVICES Diagnostic Devices § 872.1720 Pulp tester. (a) Identification. A pulp tester is an AC or... current transmitted by an electrode to stimulate the nerve tissue in the dental pulp. (b) Classification...

21 CFR 872.1720 - Pulp tester.

Code of Federal Regulations, 2014 CFR

2014-04-01

... DENTAL DEVICES Diagnostic Devices § 872.1720 Pulp tester. (a) Identification. A pulp tester is an AC or... current transmitted by an electrode to stimulate the nerve tissue in the dental pulp. (b) Classification...

Idiopathic dental pulp calcifications in a tertiary care setting in South India.

PubMed

Satheeshkumar, P S; Mohan, Minu P; Saji, Sweta; Sadanandan, Sudheesh; George, Giju

2013-01-01

Dental pulp calcifications are unique and represent the dental pulp regenerative process. Dental pulp calcifications are sometimes routine findings in oral radiographs and may later serve as an important diagnostic criterion for a hidden aspect of systemic illness. The purpose of this study was to assess the patterns and prevalence of idiopathic dental pulp calcifications in a tertiary care setting in South India. A total of 227 patients were included in the study fulfilling the inclusion criteria. Age range of the study population was from 15 to 70 years. Teeth were examined under digital panoramic radiograph. The presence or absence of pulp stones was recorded. The presence of pulp stone were categorized according to the types classified as Type I, Type IA, Type II, Type IIA, Type II B, and Type III. The frequency of occurrence of pulp stones with sex, tooth type, dental arches, and types were compared with the types of calcification. Total no. of patients with pulpal calcification were 227 [females 133 (58.59%) and males 94 (41.40%)]. The most common type between both sexes was Type I (48%). Total no. of teeth with calcification was 697; maxilla (48%), mandible (52%). The prevalence of pulp stone was found to be higher in the molars in both the arches. Most no. of pulp stones are reported at the third and fourth decade of life. Idiopathic dental pulp calcifications are incidental radiographic findings of the pulp tissue and also may be an indicator of underlying disease.

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

Polyoxometalates in oxidative delignification of chemical pulps: effect on lignin

Treesearch

Biljana Bujanovic; Sally Ralph; Richard Reiner; Kolby Hirth; Rajai Atalla

2010-01-01

Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping), the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin from the pulp without a negative effect on the cellulose; for this reason, delignification...

Laccase modification of the physical properties of bark and pulp of loblolly pine and spruce pulp

Treesearch

William Kenealy; John Klungness; Mandla Tshabalala; Eric Horn; Masood Akhtar; Roland Gleisner; Gisela Buschle-Diller

2004-01-01

Pine bark, pine pulp, and spruce pulp were reacted with laccase in the presence of phenolic laccase substrates to modify the fiber surface properties. The acid-base and dispersive characteristics of these modified steam-treated thermomechanical loblolly pine pulps were determined by inverse gas chromatography. Different combinations of substrates with laccase modified...

Determining the minimum conditions for soda-anthraquinone pulping of kenaf bast, core, and whole stalk fibers

Treesearch

James S. Han; Thomas A. Rymsza

1999-01-01

Chemical pulping of kenaf fiber is comparatively new. In this study, bast, core, and whole stalk kenaf fibers were pulped using a soda-AQ pulping process and various pulping conditions. Handsheets were evaluated for density, Canadian standard freeness, brightness, opacity, smoothness, and tensile, burst, and tear indexes and strength. The results indicate that...

46 CFR 148.325 - Wood chips; wood pellets; wood pulp pellets.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Wood chips; wood pellets; wood pulp pellets. 148.325... § 148.325 Wood chips; wood pellets; wood pulp pellets. (a) This part applies to wood chips and wood pulp... cargo hold. (b) No person may enter a cargo hold containing wood chips, wood pellets, or wood pulp...

Chapter 6: Prehydrolysis Pulping with Fermentation Coproducts

Treesearch

T.H. Wegner; C.J. Houtman; A.W. Rudie; B.L. Illman; P.J. Ince; E.M. Bilek; T.W. Jeffries

2013-01-01

Although the term “integrateed biorefinery” is new, the concept has long been familiar to the pulp and paper industry, where processes include biomass boilers providing combined heat and power, and byproducts of pulping include turpentine, fatty acids and resin acids. In the dominant kraft (or sulfate) pulping process, dissolved lignin and chemicals from the pulp...

Age-related Changes in the Alkaline Phosphatase Activity of Healthy and Inflamed Human Dental Pulp.

PubMed

Aslantas, Eda E; Buzoglu, Hatice Dogan; Karapinar, Senem Pinar; Cehreli, Zafer C; Muftuoglu, Sevda; Atilla, Pergin; Aksoy, Yasemin

2016-01-01

Alkaline phosphatase (ALP) plays an important role in inducing mineralization events in the dental pulp. This study investigated and compared the ALP levels in healthy and inflamed pulp in young and old human pulp. Tissue samples were collected from young (<30 years) and old (>60 years) donors. In both age groups, healthy human pulp (n = 18) were collected from extracted wisdom teeth. For reversible and irreversible pulpitis, pulp samples (n = 18 each) were obtained during endodontic treatment. ALP activity was assessed by spectrophotometry and immunhistochemistry. Regardless of age, reversible pulpitis group samples showed a slight elevation in ALP activity compared with normal healthy pulp. In elderly patients, ALP expression with irreversible pulpitis was significantly higher than those with a healthy pulp (P < .05). In the hyperemic state, both the young and old pulp shows a slight increase in ALP activity, whereas in irreversible pulpitis, only the old pulp shows significantly elevated ALP levels. Such an increase may trigger calcification events, which may eventually cause difficulties in endodontic treatment procedures in elderly individuals. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Failure Analysis of Cracked FS-85 Tubing and ASTAR-811C End Caps

DOE Office of Scientific and Technical Information (OSTI.GOV)

ME Petrichek

2006-02-09

Failure analyses were performed on cracked FS-85 tubing and ASTAR-811C and caps which had been fabricated as components of biaxial creep specimens meant to support materials testing for the NR Space program. During the failure analyses of cracked FS-85 tubing, it was determined that the failure potentially could be due to two effects: possible copper contamination from the EDM (electro-discharge machined) recast layer and/or an insufficient solution anneal. to prevent similar failures in the future, a more formal analysis should be done after each processing step to ensure the quality of the material before further processing. During machining of themore » ASTAR-811FC rod to form end caps for biaxial creep specimens, linear defects were observed along the center portion of the end caps. These defects were only found in material that was processed from the top portion of the ingot. The linear defects were attributed to a probable residual ingot pipe that was not removed from the ingot. During the subsequent processing of the ingot to rod, the processing temperatures were not high enough to allow self healing of the ingot's residual pipe defect. To prevent this from occurring in the future, it is necessary to ensure that complete removal of the as-melted ingot pipe is verified by suitable non-destructive evaluation (NDE).« less

Electron Beam-Induced Deposition for Atom Probe Tomography Specimen Capping Layers.

PubMed

Diercks, David R; Gorman, Brian P; Mulders, Johannes J L

2017-04-01

Six precursors were evaluated for use as in situ electron beam-induced deposition capping layers in the preparation of atom probe tomography specimens with a focus on near-surface features where some of the deposition is retained at the specimen apex. Specimens were prepared by deposition of each precursor onto silicon posts and shaped into sub-70-nm radii needles using a focused ion beam. The utility of the depositions was assessed using several criteria including composition and uniformity, evaporation behavior and evaporation fields, and depth of Ga+ ion penetration. Atom probe analyses through depositions of methyl cyclopentadienyl platinum trimethyl, palladium hexafluoroacetylacetonate, and dimethyl-gold-acetylacetonate [Me2Au(acac)] were all found to result in tip fracture at voltages exceeding 3 kV. Examination of the deposition using Me2Au(acac) plus flowing O2 was inconclusive due to evaporation of surface silicon from below the deposition under all analysis conditions. Dicobalt octacarbonyl [Co2(CO)8] and diiron nonacarbonyl [Fe2(CO)9] depositions were found to be effective as in situ capping materials for the silicon specimens. Their very different evaporation fields [36 V/nm for Co2(CO)8 and 21 V/nm for Fe2(CO)9] provide options for achieving reasonably close matching of the evaporation field between the capping material and many materials of interest.

Liquid Crystalline Thermosets from Ester, Ester-imide, and Ester-amide Oligomers

NASA Technical Reports Server (NTRS)

Dingemans, Theodorus J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)

2009-01-01

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystaloligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oli-gomers are stable forup to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oigomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.

Testing of the cytotoxic effects of sulfate pulp mill waste waters.

PubMed

Cernáková, M; Golis, E

1994-01-01

The effect of 22 technological waste water samples and of some standards was tested on bacteria, fungi, chlorococcal algae, flagellata, plant cells, cells of Tubifex tubifex, hamster cells V79 and the fish Lebistes reticulatus. Of these 22 samples, some inhibition of cell life processes was displayed by the black liquor formed in the production of paper pulp and viscose pulp, by the waste solution produced during the preparation of bleaching agents for paper pulp and viscose pulp, and by the residual liquor after hypochlorite treatment of paper pulp.

Method for rapidly determining a pulp kappa number using spectrophotometry

DOEpatents

Chai, Xin-Sheng; Zhu, Jun Yong

2002-01-01

A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.