Assessment of composition changes in demineralization and remineralization of human dentin using Raman spectroscopy/Beurteilung der Veränderungen in der Zusammensetzung von humanem Dentin durch Demineralisation und Remineralisation mittels Raman-Spektroskopie

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Zhenlin Zhan ◽  
Xianzeng Zhang ◽  
Wenqing Guo ◽  
Shusen Xie
Keyword(s):  
Raman Spectroscopy ◽  
Citric Acid ◽  
Whole Process ◽  
Before And After ◽  
Human Dentin ◽  
Acid Etch ◽  
Inorganic Constituents ◽  
Composition Changes ◽  
Chinese Subjects ◽  
Etch Time

AbstractTo evaluate the whole process of demineralization and remineralization in human dentin using Raman spectroscopy (RS).Human molars from Chinese subjects were cut into tooth sections and painted with an acid-resistant varnish leaving one dentin surface exposed. The tooth sections were immersed in 0.3% citric acid to simulate the oral natural demineralization and were randomly divided into three groups with a sample size of n=12 each: 10 min (I), 20 min (II), and 40 min (III), according to the acid etch time. Then all the samples were submitted to a remineralizing solution for 5 days. The Raman spectra were measured before and after each treatment.The result showed that although there was no new constituent formed in the whole process, the peak intensities of inorganic constituents decreased with the increase of acid etch time, while the trend of the organic constituents were the opposite. After remineralization, the peak intensities of inorganic constituents increased again.In conclusion, using RS it would be possible to efficiently monitor the demineralization and remineralization status of human dentin.

scholarly journals Demineralization, Collagen Modification and Remineralization Degree of Human Dentin after EDTA and Citric Acid Treatments

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Maria Gandolfi ◽  
Paola Taddei ◽  
Anna Pondrelli ◽  
Fausto Zamparini ◽  
Carlo Prati ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Environmental Scanning Electron Microscopy ◽  
Chelating Agent ◽  
Environmental Scanning ◽  
X Ray ◽  
Before And After ◽  
Human Dentin ◽  
Mineral Components ◽  
Mineralization Degree

The aim of the study was to investigate the effects of several decalcifying agents used as irrigant solutions in endodontic treatment on collagen and mineral components of dentin. Coronal dentin discs from five caries-free human third molars with a smear layer were treated for one minute with a chelating solution (1% Ethylenediaminetetraacetic acid (EDTA), 10% EDTA, 17% EDTA, 10% citric acid). Mineralization degree (Ca/N and P/N atomic ratios, IR Iapatite/Iamide II and I1410(carbonate)/I554(phosphate) spectroscopic ratios) and possible collagen rearrangements (collagen infrared (IR) amide II e III shifts) were evaluated by environmental scanning electron microscopy (ESEM)/energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy before and after treatment (T0) and after ageing (T24h and T2m) in simulated body fluid (SBF). At T0, analysis showed that the highest demineralizing effect was achieved using a 10% citric acid solution and 10% EDTA, while the smallest effect was observed when using 17% EDTA. No significant collagen modifications were detected upon treatment with 1% EDTA, while subtle changes were observed after the other treatments. At T24h or T2m, analyses showed the highest remineralization values for 1% EDTA and the lowest for 10% citric acid, mainly at T2m. The samples treated with 17% EDTA showed slight collagen rearrangements upon remineralization. In conclusion, the highest demineralizing effect was observed for 10% EDTA and 10% citric acid. Collagen rearrangement was found for all the treatments except for 1% EDTA. The highest remineralization capability in SBF values was recorded for 1% EDTA and the lowest for 10% citric acid. A slight collagen rearrangement upon remineralization was still present in 17% EDTA-treated samples. Clinical use as a chelating agent in the endodontic therapy of citric acid and concentrated EDTA solutions should be reconsidered.

scholarly journals Established an eco-friendly cotton fabric treating process with enhancing anti-wrinkle performance

2021 ◽  
Vol 16 ◽  
pp. 155892502110034
Author(s):  
Xiongfang Luo ◽  
Pei Cheng ◽  
Wencong Wang ◽  
Jiajia Fu ◽  
Weidong Gao
Keyword(s):  
Tensile Strength ◽  
Citric Acid ◽  
Cotton Fabric ◽  
Crosslinking Agent ◽  
Cost Effective ◽  
Waterborne Polyurethane ◽  
Cotton Fabrics ◽  
Wrinkle Resistance ◽  
Before And After ◽  
Strength Retention

This study establishes an eco-friendly anti-wrinkle treating process for cotton fabric. Sodium hydroxide-liquid ammonia pretreatment followed by 6% (w/w) PU100 adding citric acid pad-cure-dry finishing. In this process, citric acid (CA) was used as the fundamental crosslinking agent during finishing because it is a non-formaldehyde based, cost-effective and well wrinkle resistance agent. Environmental-friendly waterborne polyurethane (WPU) was used as an additive to add to the CA finishing solution. Six commercial WPUs were systematically investigated. Fabric properties like wrinkle resistance, tensile strength retention, whiteness, durable press, softness, and wettability were well investigated. Fourier transform infrared spectra and X-ray diffraction spectra were also measured and discussed before and after adding waterborne polyurethane. Tentative mechanism of the interaction among the WPU, CA, and modified cotton fabrics is provided. The effect of cotton fabric pretreatment on fabric performance was also investigated. After the eco-process’s treatment, the fabric wrinkle resistant angle was upgraded to 271 ± 7°, tensile strength retention was maintained at 66.77% ± 3.50% and CIE whiteness was elevated to 52.13 ± 3.21, which are much better than the traditional CA anti-wrinkle finishing based on mercerized cotton fabrics. This study provides useful information for textile researchers and engineers.

scholarly journals Body Composition Changes in Gastric Cancer Patients during Preoperative FLOT Therapy: Preliminary Results of an Italian Cohort Study

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 960
Author(s):  
Emanuele Rinninella ◽  
Antonia Strippoli ◽  
Marco Cintoni ◽  
Pauline Raoul ◽  
Raffaella Vivolo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Body Composition ◽  
Tumor Regression ◽  
Evaluation Criteria ◽  
Tumor Regression Grade ◽  
Skeletal Muscle Index ◽  
Before And After ◽  
Gastric Cancer Patients ◽  
The Impact ◽  
Composition Changes

Background: The impact of the new chemotherapy, fluorouracil plus leucovorin, oxaliplatin, and docetaxel (FLOT) on body composition in gastric cancer (GC) patients remains unknown. We assessed body composition changes of GC patients receiving the FLOT regimen and their impact on treatment outcomes. Methods: Preoperative pre- and post-FLOT computed tomography (CT) scans of advanced GC patients were studied. Lumbar skeletal muscle index (SMI) and adipose indices were calculated before and after FLOT. Results: A total of 26 patients were identified between April 2019 and January 2020. Nineteen patients were sarcopenic at diagnosis. The mean BMI decreased (from 24.4 ± 3.7 to 22.6 ± 3.1; p < 0.0001) as well as the SMI (from 48.74 ± 9.76 to 46.52 ± 9.98; p = 0.009) and visceral adipose index (VAI) (from 49.04 ± 31.06 to 41.99 ± 23.91; p = 0.004) during preoperative FLOT therapy. BMI, SMI, and VAI variations were not associated with toxicity, Response Evaluation Criteria in Solid Tumors (RECIST), response, delay and completion of perioperative FLOT chemotherapy, and the execution of gastrectomy; a decrease of SMI ≥ 5% was associated with a higher Mandard tumor regression grade (p = 0.01). Conclusions: Almost three-quarters (73.1%) of GC patients were sarcopenic at diagnosis. Preoperative FLOT was associated with a further reduction in SMI, BMI, and VAI. These changes were not associated with short-term outcomes.

scholarly journals Assessment of Bacteriological Quality of Sheep Carcasses, Effect Level of 2.5% Citric Acid Spray on Bacterial Contamination of Meat, and Hygiene Practices of Workers in a Selected Abattoir in Debrezeit Town, Central Ethiopia

2021 ◽  
Vol 15 ◽  
pp. 117863022110375
Author(s):  
Derebew Aynewa ◽  
Zemichael Gizaw ◽  
Aklilu Feleke Haile
Keyword(s):  
Citric Acid ◽  
Bacterial Contamination ◽  
Total Coliform ◽  
Aerobic Bacteria ◽  
Bacteriological Quality ◽  
Before And After ◽  
Effect Level ◽  
The Mean ◽  
Structured Questionnaire

Background: Meat safety is important for public health. As part of the meat chain abattoirs are required to give attention to meat hygiene and safety in order to minimize hazards. Therefore, the current study was conducted to evaluate the bacteriological quality of sheep carcasses, knowledge and hygienic practices of workers in a selected abattoir and to determine the effect level of 2.5% citric acid spray on total coliforms and aerobic bacteria load of raw sheep carcasses surfaces. Methods: A cross-sectional study design with structured questionnaire and observational checklists observation were used. A systematic random sampling technique was employed. A total of 50 sample swabs (25 swabs before citric acid spray and 25 after citric acid spray) were randomly taken from brisket, flank and rump of sheep’s carcasses. Swabs were moistened with buffered peptone water (BPW) and samples were taken by rubbing 100 cm2 (10 cm × 10 cm) area delineated by sterile aluminum template. In addition, we administered a structured questionnaire and an observational checklists to assess knowledge and hygienic practices of workers. Bacteriological quality of sheep carcasses were analyzed using the methods described by the US bacteriological analytical manual. Results: The mean count for aerobic bacteria of the sheep carcasses before and after citric acid spray were 7.2log10 CFU/ml and 6.4log10 CFU/ml, respectively. The test results also showed that 21 (84%) and 15 (60%) of the swab samples were positive before and after spraying citric acid, respectively. The mean counts for coliform bacterial of the sheep carcasses before and after citric acid spray were 3.5log10 CFU/ml and 2.9log10 CFU/ml, respectively. The mean total aerobic and coliform counts before and after citric acid spray were significantly different ( P < .05). Regarding the hygiene condition of workers, all the respondents reported that they always washed their hands with soap before and after entering the slaughtering room and 23 (53.5%) of the workers reported that they used hot water. Thirty-one (72.1%) of the workers reported that they do not used soap to wash hands after visiting toilet. Thirty-five (81.4%) of the production workers did not wear mouth mask while handling and distribute meat/carcass. On the other hand, all of the workers wore capes, gowns and boots at the time of the observation and only 18 (18.6%) of the production workers wore gloves at the time of the survey. Conclusion: The current study revealed that significant proportion of sheep carcasses were positive for total aerobic bacteria and total coliform. Moreover, the study also showed that spraying of sheep carcasses with 2.5% citric acid significantly reduced the total coliform and aerobic counts. However, we did not assessed how much spray results to this effect. Therefore, we recommended further studies to determine how much spray of 2.5% citric acid significantly reduce bacterial contamination of sheep carcasses. In addition, the abattoir has to follow the food hazard analysis critical control point (HACCP) system to minimize meat contamination during harvesting and processing. The abattoir has to also implement strict operation laws to improve hygiene conditions of the workers. In addition, the abattoir can minimize meat contamination using 2.5% citric acid as a decontaminant.

scholarly journals In Vitro Study on the Effect of a New Bioactive Desensitizer on Dentin Tubule Sealing and Bonding

2020 ◽  
Vol 11 (2) ◽  
pp. 38
Author(s):  
Minh N. Luong ◽  
Laurie Huang ◽  
Daniel C. N. Chan ◽  
Alireza Sadr
Keyword(s):  
Bond Strength ◽  
In Vitro Study ◽  
Vitro Study ◽  
Acid Pretreatment ◽  
Universal Adhesive ◽  
Cross Sectional ◽  
Before And After ◽  
Human Dentin ◽  
Microshear Bond Strength

Bioactive mineral-based dentin desensitizers that can quickly and effectively seal dentinal tubules and promote dentin mineralization are desired. This in vitro study evaluated a novel nanohydroxyapatite-based desensitizer, Predicta (PBD, Parkell), and its effect on bond strength of dental adhesives. Human dentin discs (2-mm thick) were subjected to 0.5 M EDTA to remove the smear layer and expose tubules, treated with PBD, and processed for surface and cross-sectional SEM examination before and after immersion in simulated body fluid (SBF) for four weeks (ISO 23317-2014). The effects of two dental desensitizers on the microshear bond strength of a universal adhesive and a two-step self-etch system were compared. SEM showed coverage and penetration of nanoparticles in wide tubules on the PBD-treated dentin at the baseline. After four weeks in SBF, untreated dentin showed amorphous mineral deposits while PBD-treated dentin disclosed a highly mineralized structure integrated with dentin. Desensitizers significantly reduced microshear bond strength test (MSBS) of adhesives by 15–20% on average, depending on the bonding protocol. In conclusion, PBD demonstrated effective immediate tubules sealing capability and promoted mineral crystal growth over dentin and into the tubules during SBF-storage. For bonding to desensitizer-treated dentin, a two-step self-etching adhesive or universal bond with phosphoric acid pretreatment are recommended.

Ac-impedance and Raman spectroscopy study of the electrochemical behaviour of pure aluminium in citric acid media

2001 ◽  
Vol 46 (12) ◽  
pp. 1871-1878 ◽  
Author(s):  
I.V Aoki ◽  
M.-C Bernard ◽  
S.I.Cordoba de Torresi ◽  
C Deslouis ◽  
H.G de Melo ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Citric Acid ◽  
Electrochemical Behaviour ◽  
Ac Impedance ◽  
Pure Aluminium ◽  
Spectroscopy Study ◽  
Acid Media

Influence of Temperature on Ductile-Fragile Behavior

2014 ◽  
Vol 802 ◽  
pp. 383-387
Author(s):  
C.A. Silva ◽  
R.C.R. Nascimento ◽  
M.S. Martins ◽  
M.C.S. Freitas
Keyword(s):  
Fracture Mode ◽  
Impact Energy ◽  
Impact Test ◽  
Evaluation Criteria ◽  
Test Body ◽  
Gravitational Potential Energy ◽  
Machine Component ◽  
Whole Process ◽  
Before And After ◽  
The Impact

The article to be presented will cover the whole process done in a fracture test for impact, taking into account the thermal treatment of the sample to be studied. The main objective of this article is to observe, verify, analyze and understand how the temperature difference of several samples influences the type and appearance of the fracture. The impact test have a great importance in industry, is through this that you can verify that the material is ideal for application in the production of equipment and vehicles that operate in high or low temperatures. The evaluation criteria of this trial are the energy absorbed by the sample, and the percentage of its characteristic lateral extension, and the percentage of fracture, ductile or fragile, and corresponding to a ductile fracture mode, in which the test at higher temperatures, the impact energy is relatively large, and fragile fracture mode, being one that as the temperature decreased, the impact energy will suffer decline. The most important result of the impact test is the measure of the energy absorbed by the test body to deform and break, measured by the variance of the gravitational potential energy of the hammer (machine component of the impact test) before and after impact. Therefore, providing the conclusion that the smaller the energy absorbed by the sample, more fragile it is depending on the temperature applied.

scholarly journals Carbon Dioxide Reforming of Methane over Ni Supported SiO2: Influence of the Preparation Method on the Resulting Structural Properties and Catalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 795 ◽  
Author(s):  
Hua-Ping Ren ◽  
Shao-Peng Tian ◽  
Si-Yi Ding ◽  
Gui-Qiu Huang ◽  
Min Zhu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Catalytic Activity ◽  
Citric Acid ◽  
Preparation Method ◽  
Complexing Agents ◽  
Impregnation Method ◽  
Carbon Dioxide Reforming ◽  
Highly Active ◽  
Before And After

Ni-C/SiO2 and Ni-G/SiO2 catalysts were prepared by a complexed-impregnation method using citric acid and glycine as complexing agents, respectively. Ni/SiO2 was also prepared by the conventional incipient impregnation method. All the catalysts were comparatively tested for carbon dioxide reforming of methane (CDR) at P = 1.0 atm, T = 750 °C, CO2/CH4 = 1.0, and GHSV = 60,000 mL·g−1·h−1. The results showed that Ni-C/SiO2 and Ni-G/SiO2 exhibited better CDR performance, especially regarding stability, than Ni/SiO2. The conversions of CH4 and CO2 were kept constant above 82% and 87% after 20 h of reaction over Ni-C/SiO2 and Ni-G/SiO2 while they were decreased from 81% and 88% to 56% and 59%, respectively, over the Ni/SiO2. The characterization results of the catalysts before and after the reaction showed that the particle size and the distribution of Ni, as well as the interactions between Ni and the support were significantly influenced by the preparation method. As a result, an excellent resistance to the coking deposition and the anti-sintering of Ni was obtained over the Ni-C/SiO2 and Ni-G/SiO2, leading to a highly active and stable CDR performance.

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