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Gracé J, Connor D, Bester L, Rogan C, Parsi K. Polymerisation of cyanoacrylates: The effect of sclero-embolic and contrast agents. Phlebology 2024; 39:114-124. [PMID: 37944534 DOI: 10.1177/02683555231214343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
OBJECTIVES The objective is to investigate the interaction of sclero-embolic and contrast agents with the polymerisation of medical grade n-butyl-cyanoacrylates. METHODS An in vitro spectrophotometric absorbance method was developed to detect changes in light transmission to measure n-BCA polymerisation. The initiation and the rate-of-polymerisation of mixtures of n-BCA with sclero-embolic and contrast agents were investigated. RESULTS Initiation of polymerisation: VENABLOCK™ and HISTOACRYL® were the fastest agents to polymerise, while VENASEAL™ was the slowest. Rate of polymerisation: Hypertonic saline inhibited the polymerisation of all n-BCAs, while hypertonic glucose prolonged the polymerisation rate. ETHANOL and detergent sclerosants had no effect. Contrast agents OMNIPAQUE™ and ULTRAVIST® initiated and prolonged the polymerisation of n-BCA, but in contrast, LIPIODOL® failed to initiate the process. CONCLUSIONS The commercially available medical cyanoacrylates differ in their polymerisation rates. These polymerisation rates are further affected when these products are used in conjunction with other compounds, such as sclero-embolic and contrast agents.
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Affiliation(s)
- Joseph Gracé
- Department of Dermatology, Phlebology and Fluid Mechanics Research Laboratory, St Vincent's Centre for Applied Medical Research (AMR), St. Vincent's Hospital, Sydney, NSW, Australia
- Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - David Connor
- Department of Dermatology, Phlebology and Fluid Mechanics Research Laboratory, St Vincent's Centre for Applied Medical Research (AMR), St. Vincent's Hospital, Sydney, NSW, Australia
- Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | | | | | - Kurosh Parsi
- Department of Dermatology, Phlebology and Fluid Mechanics Research Laboratory, St Vincent's Centre for Applied Medical Research (AMR), St. Vincent's Hospital, Sydney, NSW, Australia
- Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
- St Vincent's Hospital, Sydney, NSW, Australia
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Bindon K, Qi S, Kassara S, Nicolotti L, Jouin A, Beer M. Apple Pomace Compositional Data Highlighting the Proportional Contribution of Polymeric Procyanidins. Molecules 2023; 28:5494. [PMID: 37513366 PMCID: PMC10384618 DOI: 10.3390/molecules28145494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/23/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Recent years have seen an increase in research focusing on the amelioration of apple pomace waste for use in the food and nutraceutical industries. Much of this work has concentrated on the characterisation of the polyphenol composition of apple pomace materials to determine their role in conferring nutritional and health benefits. Although apples contain substantial quantities of polymeric procyanidins (condensed tannins), this class of compounds has received limited attention in apple research. This study quantified the polymeric procyanidins in apple pomace extracts using a rapid, methyl-cellulose precipitation (MCP) approach for the first time. In addition, a non-targeted metabolomics approach was applied to determine the most abundant phenolic classes present. Polymeric procyanidins were found to be the most abundant type of polyphenol in apple pomace extracts and were generally oligomeric in nature. Multivariate statistical analysis revealed that the ferric-reducing antioxidant power (FRAP) was most strongly correlated with the polymeric procyanidin concentration. Noting that polymeric procyanidins may not cross the cell layer to exert antioxidant activity in vivo, their presence in apple pomace extracts may therefore overestimate the FRAP. This work highlights the importance of polymeric procyanidins in the phenolic diversity of apple pomaces, and it is proposed that in future studies, rapid MCP assays may be used for their quantification.
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Affiliation(s)
- Keren Bindon
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Glen Osmond, Adelaide, SA 5064, Australia
| | - Song Qi
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Glen Osmond, Adelaide, SA 5064, Australia
| | - Stella Kassara
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Glen Osmond, Adelaide, SA 5064, Australia
| | - Luca Nicolotti
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Glen Osmond, Adelaide, SA 5064, Australia
- Metabolomics Australia (SA Node), Glen Osmond, Adelaide, SA 5064, Australia
| | - Alicia Jouin
- The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Glen Osmond, Adelaide, SA 5064, Australia
- Institute of Vine and Wine Science, The University of Bordeaux, 210 Chemin de Leysotte, 33882 Villenave d'Ornon, France
| | - Maggie Beer
- The Maggie Beer Foundation, SAHMRI, Adelaide, SA 5001, Australia
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Bailey CG, Nothling MD, Fillbrook LL, Vo Y, Beves JE, McCamey DR, Stenzel MH. Polydopamine as a visible-light photosensitiser for photoinitiated polymerisation. Angew Chem Int Ed Engl 2023; 62:e202301678. [PMID: 36914561 DOI: 10.1002/anie.202301678] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 03/16/2023]
Abstract
Polydopamine (PDA) is a synthetic model for melanin and has a wide range of opto-electronic properties that underpin its utility in applied and biological settings, from broadband light absorbance to possessing stable free radical species. Here, we show that PDA free radicals are photo-responsive under visible light irradiation, enabling PDA to serve as a photo-redox catalyst. Steady-state and transient electron spin resonance spectroscopy reveals a reversible amplification in semiquinone radical population within PDA under visible irradiation. This photo-response modifies the redox potential of PDA and supports sensitisation of exogenous species via photoinduced electron transfer (PET). We demonstrate the utility of this discovery by employing PDA nanoparticles to photosensitise a common diaryliodonium photoinitiator and initiate free-radical polymerisation (FRP) of vinylic monomers. In situ1H nuclear magnetic resonance spectroscopy reveals an interplay between PDA-driven photosensitising and radical quenching during FRP under blue, green, and red light. This work provides crucial insights into the photoactive free radical properties of melanin-like materials and reveals a promising new application for polydopamine as a photosensitiser.
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Affiliation(s)
| | | | | | - Yen Vo
- University of New South Wales, School of Chemistry, AUSTRALIA
| | | | - Dane R McCamey
- University of New South Wales, School of Physics, AUSTRALIA
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Narsingyani RG, Patel SM, Sood RA, Bhimani KK, Makwana SV, Savani RR. Attached Oral Mucosal Wound Closure using Blue Glue - A Prospective Clinical Study. Ann Maxillofac Surg 2023; 13:31-36. [PMID: 37711540 PMCID: PMC10499272 DOI: 10.4103/ams.ams_2_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/28/2023] [Accepted: 06/02/2023] [Indexed: 09/16/2023] Open
Abstract
Introduction Traditionally, sutures have been widely used to close intraoral wounds. Various alternatives have been developed amongst which newer tissue adhesives such as N-butyl-2-cyanoacrylate having accepted clinical properties are gaining popularity. The primary purpose of the present study is to evaluate the efficacy of N-butyl-2-cyanoacrylate for intraoral attached mucosal wound closure following alveoloplasty. Materials and Methods In this prospective split-mouth study, 25 patients requiring alveoloplasty in either maxillary or mandibular arch bilaterally with a total of 50 sites were divided into two equal groups, namely silk suture (Group 1) and cyanoacrylate (Group 2). Each patient was evaluated on the first, third, seventh, 14th and 21st post-operative days. Parameters evaluated were time taken to close incision and to achieve haemostasis, pain, oedema, post-operative wound healing, patient discomfort and possible complications. Results Time taken to close incision, time taken to achieve haemostasis, post-operative pain and oedema were found to be less in Group 2. Wound healing too was found to be better in Group 2. There was one case of adhesive peel off on the first post-operative day which was managed by reapplying the tissue adhesive. The incidence of wound dehiscence and wound infection was observed more in Group 1 on the third post-operative day. Suture breakage (16%) and adhesive dislodgement (8%) were reported on the seventh post-operative day. Discussion The use of cyanoacrylates' inherent benefits, such as improved wound seal off in attached mucosa, quick polymerisation and bacteriostatic characteristics can be beneficial when performing minor oral surgical procedures on elderly, young and mentally challenged patients.
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Affiliation(s)
- Roma Gopaldas Narsingyani
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
| | - Shital Mayank Patel
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
| | - Ramita Atul Sood
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
| | - Kruna K. Bhimani
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
| | - Sanjaykumar V. Makwana
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
| | - Rajan R. Savani
- Department of Oral and Maxillofacial Surgery, AMC Dental College and Hospital, Gujarat University, Ahmedabad, Gujarat, India
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Marovic D, Par M, Tauböck TT, Haugen HJ, Negovetic Mandic V, Wüthrich D, Burrer P, Zheng K, Attin T, Tarle Z, Boccaccini AR. Impact of Copper-Doped Mesoporous Bioactive Glass Nanospheres on the Polymerisation Kinetics and Shrinkage Stress of Dental Resin Composites. Int J Mol Sci 2022; 23:ijms23158195. [PMID: 35897771 PMCID: PMC9332616 DOI: 10.3390/ijms23158195] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 12/24/2022] Open
Abstract
We embedded copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) with antibacterial and ion-releasing properties into experimental dental composites and investigated the effect of Cu-MBGN on the polymerisation properties. We prepared seven composites with a BisGMA/TEGDMA (60/40) matrix and 65 wt.% total filler content, added Cu-MBGN or a combination of Cu-MBGN and silanised silica to the silanised barium glass base, and examined nine parameters: light transmittance, degree of conversion (DC), maximum polymerisation rate (Rmax), time to reach Rmax, linear shrinkage, shrinkage stress (PSS), maximum PSS rate, time to reach maximum PSS rate, and depth of cure. Cu-MBGN without silica accelerated polymerisation, reduced light transmission, and had the highest DC (58.8 ± 0.9%) and Rmax (9.8 ± 0.2%/s), but lower shrinkage (3 ± 0.05%) and similar PSS (0.89 ± 0.07 MPa) versus the inert reference (0.83 ± 0.13 MPa). Combined Cu-MBGN and silica slowed the Rmax and achieved a similar DC but resulted in higher shrinkage. However, using a combined 5 wt.% Cu-MBGN and silica, the PSS resembled that of the inert reference. The synergistic action of 5 wt.% Cu-MBGN and silanised silica in combination with silanised barium glass resulted in a material with the highest likelihood for dental applications in future.
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Affiliation(s)
- Danijela Marovic
- Department of Endodontics and Restorative Dentistry, University of Zagreb, 10000 Zagreb, Croatia; (V.N.M.); (Z.T.)
- Correspondence: (D.M.); (M.P.); Tel.: +385-14899203 (D.M. & M.P.)
| | - Matej Par
- Department of Endodontics and Restorative Dentistry, University of Zagreb, 10000 Zagreb, Croatia; (V.N.M.); (Z.T.)
- Correspondence: (D.M.); (M.P.); Tel.: +385-14899203 (D.M. & M.P.)
| | - Tobias T. Tauböck
- Department of Conservative and Preventive Dentistry, Centre for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland; (T.T.T.); (D.W.); (P.B.); (T.A.)
| | - Håvard J. Haugen
- Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, 0317 Oslo, Norway;
| | - Visnja Negovetic Mandic
- Department of Endodontics and Restorative Dentistry, University of Zagreb, 10000 Zagreb, Croatia; (V.N.M.); (Z.T.)
| | - Damian Wüthrich
- Department of Conservative and Preventive Dentistry, Centre for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland; (T.T.T.); (D.W.); (P.B.); (T.A.)
| | - Phoebe Burrer
- Department of Conservative and Preventive Dentistry, Centre for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland; (T.T.T.); (D.W.); (P.B.); (T.A.)
| | - Kai Zheng
- Engineering Research Center of Stomatological Translational Medicine, Nanjing Medical University, Nanjing 210029, China;
| | - Thomas Attin
- Department of Conservative and Preventive Dentistry, Centre for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland; (T.T.T.); (D.W.); (P.B.); (T.A.)
| | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, University of Zagreb, 10000 Zagreb, Croatia; (V.N.M.); (Z.T.)
| | - Aldo R. Boccaccini
- Department of Materials Science and Engineering, Institute of Biomaterials, University of Erlangen-Nuremberg, 91058 Erlangen, Germany;
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Abstract
Molecular imprinting technology defines the creation of molecularly imprinted polymer (MIP) molecules in which template molecules can place in a key-lock relationship through shape, diameter, and functional groups. Although molecular imprinting technology has been employed in different fields, its applications in drug delivery systems (DDSs) have gained momentum recently. The high loading efficiency, high stability, and controlled drug release are the primary advantages of MIPs. Here, the main components, preparation methods, and characterisation tests of MIPs are summarised, and their applications in DDSs administered by different routes are evaluated in detail. The review offers a perspective on molecular imprinting technology and applications of MIPs in drug delivery by surveying the literature approximately 1998-2021 together with the outlined prospects.
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Affiliation(s)
- Nilufer Yuksel
- Department of Pharmaceutical Technology, Ankara University, Ankara, Turkey
| | - Sevgi Tektas
- Department of Pharmaceutical Technology, Ankara University, Ankara, Turkey
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Wang WJ, Grymak A, Waddell JN, Choi JJE. The effect of light curing intensity on bulk-fill composite resins: heat generation and chemomechanical properties. Biomater Investig Dent 2021; 8:137-151. [PMID: 34622209 PMCID: PMC8491722 DOI: 10.1080/26415275.2021.1979981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Objectives The aim of this study was to assess the effect of light curing intensity and wavelength spectrum on heat generation and chemomechanical properties of bulk-fill composites. Methods Four bulk-fill restorative materials (Filtek bulk-fill, Tetric PowerFill bulk-fill, Beautifil Bulk restorative and Admira Fusion X-tra were used in this study. A total of 100 cylindrical specimens of each composite (n = 25/group) were prepared, then cured using monowave light curing unit (LCU) with a single light intensity of 1470 mW/cm2, and polywave LCU with three different light intensities (1200,2100, 3050mW/cm2). The temperature change during polymerisation was measured by five K-type thermocouples placed in each 1 mm layer from top to bottom. Hardness and degree of conversion of composites at each level were evaluated. Results were statistically analysed. Results The use of polywave LCU resulted in statistically higher peak temperatures ranging between 31.4-63.5 °C compared to the temperature generated by monowave LCU ranging between 29.5-60 °C (p < .05). Curing using polywave LCU with the highest light intensity of 3050 mW/cm2 caused the highest peak temperature irrespective of the composite types. There was no significant difference in hardness with different light curing intensities and curing times, regardless of the bulk-fill resin materials (p > .05). A positive correlation was also found between the hardness and the DoC of the four bulk-fill composites. Conclusion The change in temperature during polymerisation of bulk-fill composites were found to be proportional to the increase in light curing intensity. Mechanical properties of the bulk-fill composites were dependent on the composition and the type of photoinitiators.
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Affiliation(s)
- Wendy Jingwen Wang
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Anastasiia Grymak
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - John Neil Waddell
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Joanne Jung Eun Choi
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Dundić A, Rajić Brzović V, Vlajnić G, Kalibović Govorko D, Medvedec Mikić I. A measurement of irradiance of light-curing units in dental offices in three Croatian cities. Med Glas (Zenica) 2021; 18:505-509. [PMID: 34308622 DOI: 10.17392/1323-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/12/2021] [Accepted: 03/10/2021] [Indexed: 06/13/2023]
Abstract
Aim To determine irradiance of light-curing units (LCUs) in dental offices in three Croatian cities and to compare irradiance values with the age and model of LCUs. Methods Private and public dental offices in three most prominent cities in Croatia (Rijeka, Split and Zagreb) were included in this study. In total, 195 LCUs were tested, using radiometer Ivoclar Bluephase Meter 2 for irradiance (mW/cm2 ). The minimum acceptable value was set at 400 mW/cm2 . The age, model and difference between declared and measured irradiance of the LCUs were also determined. Of the total of 195 LCUs, 190 (98%) were LED (light-emitting diode) and 5 (2%) were QTH (quartz-tungsten - halogen). Results The mean age of tested LCUs was 4.43±3.4 years; the oldest was in Rijeka, 5.2±3.8 years. The overall mean irradiance for all three cities was 806.4 mW/cm2 (p=0.0004). Of all LCUs, 11.3% were considered clinically unacceptable with irradiance of less than 400 mW/cm2 . Of all tested LCUs 42% (p=0.0005) had a 30% lower value of irradiance than the manufacturer of the LCU declared. In 73% tested LCUs, there was a matching between measured and declared irradiance. The age and model of LCUs had the most significant impact on irradiance. Conclusion The most commonly used LCU included in dental offices was LED. Mean irradiance was good enough to secure adequate polymerization of resin-based materials. Irradiance decreases with usage time of LCU.
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Affiliation(s)
- Ante Dundić
- Medical Care Facility A2 Dental, Trogir, Croatia
| | - Valentina Rajić Brzović
- Department of Endodontics and Restorative Stomatology, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | | | - Danijela Kalibović Govorko
- Department of Orthodontics, Study Programme of Dental Medicine, School of Medicine, University of Split, Split, Croatia
- University Hospital of Split, Split, Croatia
| | - Ivana Medvedec Mikić
- University Hospital of Split, Split, Croatia
- Department of Endodontics and Restorative Dental Medicine, Study Programme of Dental Medicine, School of Medicine, University of Split, Split, Croatia
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Balhaddad AA, Marghalani AA, Raderman MA, Miginsky E, Massey W, Strassler H, Anne Melo M. Hands-on training based on quantifying radiant exposure improves how dental students cure composites: Skill retention at 2-year follow-up. Eur J Dent Educ 2021; 25:582-591. [PMID: 33220151 DOI: 10.1111/eje.12635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 05/27/2023]
Abstract
INTRODUCTION The durability and longevity of composite restoration are much dependent on the accurate delivery of the energy required to polymerise the material. This study aimed to investigate the extent to which undergraduate dental students acquire and retain light-curing skills following hands-on training. MATERIALS AND METHODS Hands-on training comprises faculty tutoring for critical aspects of the light-curing procedure, such as distance and angulation of the light-curing tip. Assessments of the students' ability to deliver a specified radiant exposure to class III and I simulated RBCs using a dental simulator (MARC-PS® ) at three different time points after the training. Data were analysed using repeated measure ANOVA. RESULTS Immediately after the training, students' performance on curing was improved (p < .05). Overall, the radiant exposure increased after training, but the students lost some of the benefits with time. For curing in the anterior section (anterior sensor-class III), the mean radiant exposure values increased by approximately 20% after the training. After 2 years, the values were 15% greater than baseline values. For curing in the posterior section (posterior sensor-class I), the mean radiant exposure values increased by approximately 150% after the training. A significant decrease (p < .05) was observed; however, the radiant exposure values were still 82% greater than the baseline after 2 years. CONCLUSION A hands-on training dedicated to light-curing procedures facilitated acquisition and retention up to a 2-year follow-up of skill on how light cure composite inside the mouth. The training was more relevant for curing in posterior areas, where orientation can significantly impact light-curing. A hands-on training where the radiant exposure can be measure gave objective measurement metrics to guide the curing performance. This approach is an effective means of teaching practical skills to dental students.
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Affiliation(s)
- Abdulrahman A Balhaddad
- Dental Biomedical Science PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Abdullah A Marghalani
- Department of Preventive Dentistry, Faculty of Dentistry, Um Al-Qura University, Makkah, Saudi Arabia
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Michael A Raderman
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Elaine Miginsky
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Ward Massey
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Howard Strassler
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Mary Anne Melo
- Dental Biomedical Science PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
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Wonanke ADD, Bennett P, Caldwell L, Addicoat MA. Role of Host-Guest Interaction in Understanding Polymerisation in Metal-Organic Frameworks. Front Chem 2021; 9:716294. [PMID: 34368085 PMCID: PMC8333864 DOI: 10.3389/fchem.2021.716294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Metal-organic frameworks, MOFs, offer an effective template for polymerisation of polymers with precisely controlled structures within the sub-nanometre scales. However, synthetic difficulties such as monomer infiltration, detailed understanding of polymerisation mechanisms within the MOF nanochannels and the mechanism for removing the MOF template post polymerisation have prevented wide scale implementation of polymerisation in MOFs. This is partly due to the significant lack in understanding of the energetic and atomic-scale intermolecular interactions between the monomers and the MOFs. Consequently in this study, we explore the interaction of varied concentration of styrene, and 3,4-ethylenedioxythiophene (EDOT), at the surface and in the nanochannel of Zn2(1,4-ndc)2 (dabco), where 1,4-ndc = 1,4-naphthalenedicarboxylate and dabco = 1,4-diazabicyclo[2.2.2]octane. Our results showed that the interactions between monomers are stronger in the nanochannels than at the surfaces of the MOF. Moreover, the MOF-monomer interactions are strongest in the nanochannels and increase with the number of monomers. However, as the number of monomers increases, the monomers turn to bind more strongly at the surface leading to a potential agglomeration of the monomers at the surface.
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Affiliation(s)
- A D Dinga Wonanke
- Department of Chemistry and Forensics, Nottingham Trent University, Nottingham, United Kingdom
| | - Poppy Bennett
- Department of Chemistry and Forensics, Nottingham Trent University, Nottingham, United Kingdom
| | - Lewis Caldwell
- Department of Chemistry and Forensics, Nottingham Trent University, Nottingham, United Kingdom
| | - Matthew A Addicoat
- Department of Chemistry and Forensics, Nottingham Trent University, Nottingham, United Kingdom
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Demir B, Perli G, Chan KY, Duchet-Rumeau J, Livi S. Molecular-Level Investigation of Cycloaliphatic Epoxidised Ionic Liquids as a New Generation of Monomers for Versatile Poly(Ionic Liquids). Polymers (Basel) 2021; 13:polym13091512. [PMID: 34067227 PMCID: PMC8125863 DOI: 10.3390/polym13091512] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 11/16/2022] Open
Abstract
Recently, a new generation of polymerised ionic liquids with high thermal stability and good mechanical performances has been designed through novel and versatile cycloaliphatic epoxy-functionalised ionic liquids (CEILs). From these first promising results and unexplored chemical structures in terms of final properties of the PILs, a computational approach based on molecular dynamics simulations has been developed to generate polymer models and predict the thermo–mechanical properties (e.g., glass transition temperature and Young’s modulus) of experimentally investigated CEILs for producing multi-functional polymer materials. Here, a completely reproducible and reliable computational protocol is provided to design, test and tune poly(ionic liquids) based on epoxidised ionic liquid monomers for future multi-functional thermoset polymers.
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Affiliation(s)
- Baris Demir
- Centre for Theoretical and Computational Molecular Science, The Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
- Correspondence:
| | - Gabriel Perli
- Ingénierie des Matériaux Polymères, Université de Lyon, CNRS, UMR 5223, INSA Lyon, F-69621 Villeurbanne, France; (G.P.); (J.D.-R.); (S.L.)
| | - Kit-Ying Chan
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China;
| | - Jannick Duchet-Rumeau
- Ingénierie des Matériaux Polymères, Université de Lyon, CNRS, UMR 5223, INSA Lyon, F-69621 Villeurbanne, France; (G.P.); (J.D.-R.); (S.L.)
| | - Sébastien Livi
- Ingénierie des Matériaux Polymères, Université de Lyon, CNRS, UMR 5223, INSA Lyon, F-69621 Villeurbanne, France; (G.P.); (J.D.-R.); (S.L.)
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Wen Q, Tang A, Chen C, Liu Y, Xiao C, Tan J, Li D. Impact of Backbone Amide Substitution at the Meta- and Para-Positions on the Gas Barrier Properties of Polyimide. Materials (Basel) 2021; 14:2097. [PMID: 33919262 DOI: 10.3390/ma14092097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 11/16/2022]
Abstract
This study designed and synthesised a meta-amide-substituted dianiline monomer (m-DABA) as a stereoisomer of DABA, a previously investigated para-amide-substituted dianiline monomer. This new monomer was polymerised with pyromellitic dianhydride (PMDA) to prepare a polyimide film (m-DABPI) in a process similar to that employed in a previous study. The relationship between the substitution positions on the monomer and the gas barrier properties of the polyimide film was investigated via molecular simulation, wide-angle X-ray diffraction (WXRD), and positron annihilation lifetime spectroscopy (PALS) to gain deeper insights into the gas barrier mechanism. The results showed that compared with the para-substituted DABPI, the m-DABPI exhibited better gas barrier properties, with a water vapour transmission rate (WVTR) and an oxygen transmission rate (OTR) as low as 2.8 g·m−2·d−1 and 3.3 cm3·m−2·d−1, respectively. This was because the meta-linked polyimide molecular chains were more tightly packed, leading to a smaller free volume and lower molecular chain mobility. These properties are not conducive to the permeation of small molecules into the film; thus, the gas barrier properties were improved. The findings have significant implications for the structural design of high-barrier materials and could promote the development of flexible display technology.
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Ronzoni R, Heyer‐Chauhan N, Fra A, Pearce AC, Rüdiger M, Miranda E, Irving JA, Lomas DA. The molecular species responsible for α 1 -antitrypsin deficiency are suppressed by a small molecule chaperone. FEBS J 2021; 288:2222-2237. [PMID: 33058391 PMCID: PMC8436759 DOI: 10.1111/febs.15597] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/28/2020] [Accepted: 10/12/2020] [Indexed: 12/16/2022]
Abstract
The formation of ordered Z (Glu342Lys) α1 -antitrypsin polymers in hepatocytes is central to liver disease in α1 -antitrypsin deficiency. In vitro experiments have identified an intermediate conformational state (M*) that precedes polymer formation, but this has yet to be identified in vivo. Moreover, the mechanism of polymer formation and their fate in cells have been incompletely characterised. We have used cell models of disease in conjunction with conformation-selective monoclonal antibodies and a small molecule inhibitor of polymerisation to define the dynamics of polymer formation, accumulation and secretion. Pulse-chase experiments demonstrate that Z α1 -antitrypsin accumulates as short-chain polymers that partition with soluble cellular components and are partially secreted by cells. These precede the formation of larger, insoluble polymers with a longer half-life (10.9 ± 1.7 h and 20.9 ± 7.4 h for soluble and insoluble polymers, respectively). The M* intermediate (or a by-product thereof) was identified in the cells by a conformation-specific monoclonal antibody. This was completely abrogated by treatment with the small molecule, which also blocked the formation of intracellular polymers. These data allow us to conclude that the M* conformation is central to polymerisation of Z α1 -antitrypsin in vivo; preventing its accumulation represents a tractable approach for pharmacological treatment of this condition; polymers are partially secreted; and polymers exist as two distinct populations in cells whose different dynamics have likely consequences for the aetiology of the disease.
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Affiliation(s)
| | | | - Annamaria Fra
- Department of Molecular and Translational MedicineUniversity of BresciaItaly
| | | | | | - Elena Miranda
- Department of Biology and Biotechnologies‘Charles Darwin’ and Pasteur Institute – Cenci‐Bolognetti FoundationSapienza University of RomeItaly
| | - James A. Irving
- UCL RespiratoryDivision of MedicineUniversity College LondonUK
| | - David A. Lomas
- UCL RespiratoryDivision of MedicineUniversity College LondonUK
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14
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Anke F, Boye S, Spannenberg A, Lederer A, Heller D, Beweries T. Dehydro polymerisation of Methylamine Borane and an N-Substituted Primary Amine Borane Using a PNP Fe Catalyst. Chemistry 2020; 26:7889-7899. [PMID: 32118328 PMCID: PMC7383739 DOI: 10.1002/chem.202000809] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Indexed: 01/30/2023]
Abstract
Dehydropolymerisation of methylamine borane (H3 B⋅NMeH2 ) using the well-known iron amido complex [(PNP)Fe(H)(CO)] (PNP=N(CH2 CH2 PiPr2 )2 ) (1) gives poly(aminoborane)s by a chain-growth mechanism. In toluene, rapid dehydrogenation of H3 B⋅NMeH2 following first-order behaviour as a limiting case of a more general underlying Michaelis-Menten kinetics is observed, forming aminoborane H2 B=NMeH, which selectively couples to give high-molecular-weight poly(aminoborane)s (H2 BNMeH)n and only traces of borazine (HBNMe)3 by depolymerisation after full conversion. Based on a series of comparative experiments using structurally related Fe catalysts and dimethylamine borane (H3 B⋅NMe2 H) polymer formation is proposed to occur by nucleophilic chain growth as reported earlier computationally and experimentally. A silyl functionalised primary borane H3 B⋅N(CH2 SiMe3 )H2 was studied in homo- and co-dehydropolymerisation reactions to give the first examples for Si containing poly(aminoborane)s.
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Affiliation(s)
- Felix Anke
- Leibniz-Institut für Katalyse e.V.Albert-Einstein-Str. 29a18059RostockGermany
| | - Susanne Boye
- Leibniz-Institut für Polymerforschung DresdenHohe Str. 601069DresdenGermany
| | - Anke Spannenberg
- Leibniz-Institut für Katalyse e.V.Albert-Einstein-Str. 29a18059RostockGermany
| | - Albena Lederer
- Leibniz-Institut für Polymerforschung DresdenHohe Str. 601069DresdenGermany
- Technische Universität Dresden01062DresdenGermany
| | - Detlef Heller
- Leibniz-Institut für Katalyse e.V.Albert-Einstein-Str. 29a18059RostockGermany
| | - Torsten Beweries
- Leibniz-Institut für Katalyse e.V.Albert-Einstein-Str. 29a18059RostockGermany
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15
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Cangul S, Adiguzel O, Tekin S. Comparison of Cytotoxicity of Four Different Adhesive Materials Before and After Polymerisation. Oral Health Prev Dent 2020; 18:43-52. [PMID: 32051970 DOI: 10.3290/j.ohpd.a43940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
INTRODUCTION The aim of this study was to make a quantitative comparison of the cytotoxic potentials of four different polymerised and unpolymerised self-etching adhesives which were newly used clinically. MATERIALS AND METHODS Cytotoxic effects of both polymerised and unpolymerised forms of all test adhesives were evaluated against L929 cell line using the MTT test. The activity for unpolymerised adhesives was assessed in different doses and incubation times manner. On the other hand, cytotoxicity of the polymerised adhesives prepared at different extraction times were evaluated as dependent on incubation times. Two-Way Variance Analysis and Bonferroni post-test was used for statistical evaluation. RESULTS There were statistically significant differences between the groups (p < 0.05). In general, it was shown that unpolymerised and polymerised forms of each of the test compounds exhibited a time-dependent cytotoxic effect. However, the effect on polymerised forms was found to be independent of the duration of the extraction, while the effect on the unpolymerised forms increased dose-dependently. It was also determined that the most cytotoxic material in the unpolymerised form was Dentsply and in the polymerised form was Tokuyama. CONCLUSIONS Dentsply should be preferred over Tokuyama to be able to provide clinically long-lasting restorations.
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16
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Barszcz M, Taciak M, Tuśnio A, Święch E, Skomiał J. Dose-dependent effects of two inulin types differing in chain length on the small intestinal morphology, contractility and proinflammatory cytokine gene expression in piglets. Arch Anim Nutr 2019; 74:107-120. [PMID: 31852279 DOI: 10.1080/1745039x.2019.1697140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Inulin is a linear fructose polymer which may affect small intestinal physiology. The effects of dietary level of two inulin types on morphology, contractility and proinflammatory cytokine gene expression in the small intestine of piglets were investigated. Fifty six piglets were divided into seven groups fed diets without inulin addition or with 1%, 2% or 3% of inulin with an average degree of polymerisation of 10 (IN10) or 23 (IN23). All diets were offered from day 10 of life for 40 d. Feeding IN10 diets did not affect villous height to crypt depth ratio in the duodenum, while in the jejunum the 2% IN10 diet increased it as compared to other groups. Jejunal muscle contractions induced by electrical field stimulation were impaired by the 2% and 3% IN10 diets. The ileal expression of interleukin-12p40 was decreased by the 2% IN10 diet. There was no effect of IN23 level on villous height to crypt depth ratio in any segment of the small intestine as well as on jejunal motility. The 2% and 3% IN23 diets decreased the jejunal expression of tumour necrosis factor-α. In conclusion, IN10 is more active in the small intestine than IN23. At the 2% dietary level, it increases absorptive area in the jejunum, but may slightly impair smooth muscle contractions.
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Affiliation(s)
- Marcin Barszcz
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Marcin Taciak
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Anna Tuśnio
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Ewa Święch
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Jacek Skomiał
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
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Vaccari M, Castro FD. Non-conventional stabilisation/solidification treatment of industrial wastes with residual powdered paints. Waste Manag Res 2019; 37:1012-1024. [PMID: 31328693 DOI: 10.1177/0734242x19860178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Stabilisation/solidification technologies are widely used for rendering industrial wastes inert. In this study, residual powdered paints were applied to treat different types of industrial wastes by stabilisation/solidification: Fumes from steel-making process, sludge from coagulation/flocculation treatments and powders from brushing and polishing metallic objects. Stabilisation/solidification trials were performed both under static conditions and in motion. It was observed that the residual paints could polymerise well in 60 min at 120 °C. The addition of water during the treatment resulted in highly porous and friable materials and, therefore, is not recommended. The mixture between wastes and paint influenced polymerisation. Specific heating conditions needed to be tested for each waste, varying from 80 °C to 150 °C. Significant reduction on leachability after treatment could be reached in most cases. Reduction on chlorides release up to 92.0% were achieved. Contents of other elements on the leachates, such as copper, molybdenum, nickel, zinc and dissolved organic carbon, could also be reduced in percentages up to 96.9%, 97.6%, 98.8%, 95.7% and 96.9%, respectively. For some types of wastes, however, especially those containing high contents of copper and mineral oils, the treatment was ineffective. Polymerisation in motion apparently improved binding capacity, but tests with increased content of paints are recommended to reduce the release of dissolved organic carbon.
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Affiliation(s)
- Mentore Vaccari
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Brescia, Italy
| | - Francine Duarte Castro
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Brescia, Italy
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18
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Lowe CJ, DiMartini ET, Mirmajlesi KR, Gormley AJ, Shreiber DI. Free radical-mediated targeting and immobilization of coupled payloads. J Drug Target 2019; 27:1025-1034. [PMID: 30782037 DOI: 10.1080/1061186x.2019.1584807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Targeted drug delivery is a promising approach to enhance the accumulation of therapies in diseased tissues while limiting off-site effects. Ligand-receptor interactions are traditionally identified to deliver therapies, and although specific, this can be costly and often suffers from limited sensitivity. An emerging approach is to target intermediary species that modulate disease progression. Here, we propose novel methods of targeting therapies by using native free radicals as a homing signal. Elevated concentrations of free radicals are a characteristic comorbidity of many different diseases. In polymer chemistry, free radicals are frequently used to initiate crosslinking reactions. We proposed that free radicals elevated in injury sites are capable of inducing crosslinking of acrylate groups on polymer chains. Coupling payloads to the polymer then allow for specific targeting of therapies to areas with elevated free radicals. We demonstrate in vitro proof-of-principle of this approach. Reactive oxygen species (ROS) initiated crosslinking of acrylated PEGs, which immobilized a fluorescent payload within tissue mimics. The cross-linking efficiency and immobilization potential varied with the polymer chain length, suggesting that a tuneable platform can be achieved. Together these results provide promising proof-of-concept for using free radicals to specifically target and sustain nearly endless payloads to disease sites.
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Affiliation(s)
- Christopher J Lowe
- a Department of Biomedical Engineering, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - Emily T DiMartini
- a Department of Biomedical Engineering, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - Keana R Mirmajlesi
- a Department of Biomedical Engineering, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - Adam J Gormley
- a Department of Biomedical Engineering, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - David I Shreiber
- a Department of Biomedical Engineering, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
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Savoca MP, Tonoli E, Atobatele AG, Verderio EAM. Biocatalysis by Transglutaminases: A Review of Biotechnological Applications. Micromachines (Basel) 2018; 9:E562. [PMID: 30715061 DOI: 10.3390/mi9110562] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/23/2018] [Indexed: 02/08/2023]
Abstract
The biocatalytic activity of transglutaminases (TGs) leads to the synthesis of new covalent isopeptide bonds (crosslinks) between peptide-bound glutamine and lysine residues, but also the transamidation of primary amines to glutamine residues, which ultimately can result into protein polymerisation. Operating with a cysteine/histidine/aspartic acid (Cys/His/Asp) catalytic triad, TGs induce the post-translational modification of proteins at both physiological and pathological conditions (e.g., accumulation of matrices in tissue fibrosis). Because of the disparate biotechnological applications, this large family of protein-remodelling enzymes have stimulated an escalation of interest. In the past 50 years, both mammalian and microbial TGs polymerising activity has been exploited in the food industry for the improvement of aliments' quality, texture, and nutritive value, other than to enhance the food appearance and increased marketability. At the same time, the ability of TGs to crosslink extracellular matrix proteins, like collagen, as well as synthetic biopolymers, has led to multiple applications in biomedicine, such as the production of biocompatible scaffolds and hydrogels for tissue engineering and drug delivery, or DNA-protein bio-conjugation and antibody functionalisation. Here, we summarise the most recent advances in the field, focusing on the utilisation of TGs-mediated protein multimerisation in biotechnological and bioengineering applications.
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20
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Plaza DD, Strobel V, Heer PKKS, Sellars AB, Hoong S, Clark AJ, Lapkin AA. Direct valorisation of waste cocoa butter triglycerides via catalytic epoxidation, ring-opening and polymerisation. J Chem Technol Biotechnol 2017; 92:2254-2266. [PMID: 28919656 PMCID: PMC5575473 DOI: 10.1002/jctb.5292] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Development of circular economy requires significant advances in the technologies for valorisation of waste, as waste becomes new feedstock. Food waste is a particularly important feedstock, containing large variation of complex chemical functionality. Although most food waste sources are complex mixtures, waste from food processing, no longer suitable for the human food chain, may also represent relatively clean materials. One such material requiring valorisation is cocoa butter. RESULTS Epoxidation of a triglyceride from a food waste source, processing waste cocoa butter, into the corresponding triglyceride epoxide was carried out using a modified Ishii-Venturello catalyst in batch and continuous flow reactors. The batch reactor achieved higher yields due to the significant decomposition of hydrogen peroxide in the laminar flow tubular reactor. Integral and differential models describing the reaction and the phase transfer kinetics were developed for the epoxidation of cocoa butter and the model parameters were estimated. Ring-opening of the epoxidised cocoa butter was undertaken to provide polyols of varying molecular weight (Mw = 2000-84 000 Da), hydroxyl value (27-60 mg KOH g-1) and acid value (1-173 mg KOH g-1), using either aqueous ortho-phosphoric acid (H 3 PO 4) or boron trifluoride diethyl etherate (BF 3·OEt2)-mediated oligomerisation in bulk, using hexane or tetrahydrofuran (THF) as solvents. The thermal and tensile properties of the polyurethanes obtained from the reaction of these polyols with 4,4'-methylene diphenyl diisocyanate (MDI) are described. CONCLUSION The paper presents a complete valorisation scheme for a food manufacturing industry waste stream, starting from the initial chemical transformation, developing a process model for the design of a scaled-up process, and leading to synthesis of the final product, in this case a polymer. This work describes aspects of optimisation of the conversion route, focusing on clean synthesis and also demonstrates the interdisciplinary nature of the development projects, requiring input from different areas of chemistry, process modelling and process design. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
| | - Vinzent Strobel
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeUK
- Aachener Verfahrenstechnik – Process Systems EngineeringRWTH Aachen UniversityAachenGermany
| | | | | | | | | | - Alexei A Lapkin
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeUK
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21
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Liu Y, Hu Q, Zhang F, Tuck C, Irvine D, Hague R, He Y, Simonelli M, Rance GA, Smith EF, Wildman RD. Additive Manufacture of Three Dimensional Nanocomposite Based Objects through Multiphoton Fabrication. Polymers (Basel) 2016; 8:polym8090325. [PMID: 30974598 PMCID: PMC6431936 DOI: 10.3390/polym8090325] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/27/2016] [Accepted: 08/04/2016] [Indexed: 11/16/2022] Open
Abstract
Three-dimensional structures prepared from a gold-polymer composite formulation have been fabricated using multiphoton lithography. In this process, gold nanoparticles were simultaneously formed through photoreduction whilst polymerisation of two possible monomers was promoted. The monomers, trimethylopropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) were mixed with a gold salt, but it was found that the addition of a ruthenium(II) complex enhanced both the geometrical uniformity and integrity of the polymerised/reduced material, enabling the first production of 3D gold-polymer structures by single step multiphoton lithography.
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Affiliation(s)
- Yaan Liu
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Qin Hu
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Fan Zhang
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Christopher Tuck
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Derek Irvine
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Richard Hague
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Yinfeng He
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Marco Simonelli
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Graham A Rance
- Nanoscale and Microscale Research Centre, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Emily F Smith
- Nanoscale and Microscale Research Centre, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Ricky D Wildman
- Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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Whyte CS, Chernysh IN, Domingues MM, Connell S, Weisel JW, Ariens RAS, Mutch NJ. Polyphosphate delays fibrin polymerisation and alters the mechanical properties of the fibrin network. Thromb Haemost 2016; 116:897-903. [PMID: 27610454 PMCID: PMC5228039 DOI: 10.1160/th16-01-0062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 08/07/2016] [Indexed: 12/23/2022]
Abstract
Polyphosphate (polyP) binds to fibrin(ogen) and alters fibrin structure, generating a heterogeneous network composed of ‘knots’ interspersed by large pores. Here we show platelet-derived polyP elicits similar structural changes in fibrin and examine the mechanism by which polyP alters fibrin structure. Polymerisation of fibrinogen with thrombin and CaCl2 was studied using spinning disk confocal (SDC) microscopy. PolyP delayed fibrin polymerisation generating shorter protofibrils emanating from a nucleus-type structure. Consistent with this, cascade blue-polyP accumulated in fibrin ‘knots’. Protofibril formation was visualized by atomic force microscopy (AFM) ± polyP. In the presence of polyP abundant monomers of longer length were visualised by AFM, suggesting that polyP binds to monomeric fibrin. Shorter oligomers form in the presence of polyP, consistent with the stunted protofibrils visualised by SDC microscopy. We examined whether these structural changes induced by polyP alter fibrin’s viscoelastic properties by rheometry. PolyP reduced the stiffness (G’) and ability of the fibrin network to deform plastically G’’, but to different extents. Consequently, the relative plastic component (loss tangent (G’’/G’)) was 61 % higher implying that networks containing polyP are less stiff and more plastic. Local rheological measurements, performed using magnetic tweezers, indicate that the fibrin dense knots are stiffer and more plastic, reflecting the heterogeneity of the network. Our data show that polyP impedes fibrin polymerisation, stunting protofibril growth producing ‘knotted’ regions, which are rich in fibrin and polyP. Consequently, the mechanical properties of the fibrin network are altered resulting in clots with overall reduced stiffness and increased ability to deform plastically.
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Affiliation(s)
| | | | | | | | | | | | - Nicola J Mutch
- Dr Nicola J. Mutch, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, AB25 2ZD, UK, Tel.: +44 1224 437492, E-mail:
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Khan MJH, Hussain MA, Mujtaba IM. Developed Hybrid Model for Propylene Polymerisation at Optimum Reaction Conditions. Polymers (Basel) 2016; 8:E47. [PMID: 30979141 PMCID: PMC6432575 DOI: 10.3390/polym8020047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/20/2016] [Accepted: 01/28/2016] [Indexed: 11/16/2022] Open
Abstract
A statistical model combined with CFD (computational fluid dynamic) method was used to explain the detailed phenomena of the process parameters, and a series of experiments were carried out for propylene polymerisation by varying the feed gas composition, reaction initiation temperature, and system pressure, in a fluidised bed catalytic reactor. The propylene polymerisation rate per pass was considered the response to the analysis. Response surface methodology (RSM), with a full factorial central composite experimental design, was applied to develop the model. In this study, analysis of variance (ANOVA) indicated an acceptable value for the coefficient of determination and a suitable estimation of a second-order regression model. For better justification, results were also described through a three-dimensional (3D) response surface and a related two-dimensional (2D) contour plot. These 3D and 2D response analyses provided significant and easy to understand findings on the effect of all the considered process variables on expected findings. To diagnose the model adequacy, the mathematical relationship between the process variables and the extent of polymer conversion was established through the combination of CFD with statistical tools. All the tests showed that the model is an excellent fit with the experimental validation. The maximum extent of polymer conversion per pass was 5.98% at the set time period and with consistent catalyst and co-catalyst feed rates. The optimum conditions for maximum polymerisation was found at reaction temperature (RT) 75 °C, system pressure (SP) 25 bar, and 75% monomer concentration (MC). The hydrogen percentage was kept fixed at all times. The coefficient of correlation for reaction temperature, system pressure, and monomer concentration ratio, was found to be 0.932. Thus, the experimental results and model predicted values were a reliable fit at optimum process conditions. Detailed and adaptable CFD results were capable of giving a clear idea of the bed dynamics at optimum process conditions.
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Affiliation(s)
- Mohammad Jakir Hossain Khan
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Mohd Azlan Hussain
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
- UM Power Energy Dedicated Advanced Centre (UMPEDAC).
| | - Iqbal Mohammed Mujtaba
- Chemical Engineering Division, School of Engineering, University of Bradford, Bradford BD7 1DP, UK.
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Abstract
Mercury is one of the most toxic pollutants, with high capacity of accumulation in living organism, causing important human health problems. Therefore, the mercury removal from water is an important research goal. In a previous work, an extractant agent [di(2-ethylhexyl)phosphoric acid] was microencapsulated in poly(styrene-co-divinylbenzene) by means of suspension polymerisation using toluene as diluent. In this study, this recipe has been modified changing the toluene by heptane and extended to four additional extractants (trioctylamine, trioctylmethylammonium chloride [TOMAC], tributyl phosphate and trioctylphosphine oxide). The polluting potential of the waste liquid from the process was measured by total organic carbon and chemical oxygen demand analyses. The morphology, particle size and distribution were studied by scanning electron microscopy and low angle laser light scattering. The amount of extractant agent into the microcapsules and the microencapsulation efficiency were determined by thermogravimetric analysis and the mercury removal capacity by equilibrium studies. Microcapsules containing TOMAC demonstrated to be the best material for the mercury removal and retention.
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Affiliation(s)
- Ángela Alcázar
- a Department of Chemical Engineering , Institute of Chemical and Environmental Technology, University of Castilla-La Mancha , Ciudad Real , Spain
| | - Manuel Carmona
- a Department of Chemical Engineering , Institute of Chemical and Environmental Technology, University of Castilla-La Mancha , Ciudad Real , Spain
| | - Ana M Borreguero
- a Department of Chemical Engineering , Institute of Chemical and Environmental Technology, University of Castilla-La Mancha , Ciudad Real , Spain
| | - Antonio de Lucas
- a Department of Chemical Engineering , Institute of Chemical and Environmental Technology, University of Castilla-La Mancha , Ciudad Real , Spain
| | - Juan F Rodríguez
- a Department of Chemical Engineering , Institute of Chemical and Environmental Technology, University of Castilla-La Mancha , Ciudad Real , Spain
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25
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Mazzei P, Fusco L, Piccolo A. Acetone-induced polymerisation of 3-aminopropyltrimethoxysilane (APTMS) as revealed by NMR spectroscopy. Magn Reson Chem 2014; 52:383-388. [PMID: 24757082 DOI: 10.1002/mrc.4076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/20/2014] [Accepted: 03/27/2014] [Indexed: 06/03/2023]
Abstract
We followed the reactivity of acetone with 3-aminopropyltrimethoxysilane, a potential organosilane coupling agent, by (1)H, (13)C and (29)Si NMR spectroscopy. Selective 1D and 2D-edited NMR experiments significantly contributed to simplify the spectral complexity of reaction solution and elucidated molecular structures within progressive reaction phases. The course of the 3-aminopropyltrimethoxysilane reaction with acetone was shown by a progressive decrease of both reactants, and a concomitant appearance of water and methanol, due to formation of imine and hydrolysis of alkoxysilane groups, respectively. The occurrence of multiple siloxane linkages in a progressively larger cross-linked macromolecular structure was revealed by DOSY-NMR experiments and new signals in (29)Si-NMR spectra at different reaction times. The NMR approach described here may be applied to investigate the reactivity of other γ-aminopropylalkoxysilanes and contribute to define procedures for the preparation of silica-based materials.
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Affiliation(s)
- Pierluigi Mazzei
- Centro Interdipartimentale per la Risonanza Magnetica Nucleare, Università di Napoli Federico II, Via Università 100, 80055, Portici, Italy
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26
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Lane J, Martin T, Weeks HP, Jiang WG. Structure and role of WASP and WAVE in Rho GTPase signalling in cancer. Cancer Genomics Proteomics 2014; 11:155-165. [PMID: 24969695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
A major factor controlling the metastatic nature of cancer cells is their motility. Alterations in the signalling pathways controlling its regulation can lead to tumor cell invasion and metastasis. Directional motility involves protrusion of the cell's leading edge, via formation of filopodia and lamellipodia, adhesion to the substrate followed by tail retraction and de-adhesion. Rho GTPase binding proteins function as activators of the actin cytoskeleton and are key players in the transendothelial migration of cancer cells. Activation of the specific GTPases Rho, Rac1 and Cdc42 results in formation of actin stress fibres, membrane ruffles, lamellipodia and filopodia respectively and in cortical actin assembly. Pathways through which Rho GTPases elicit these effects are through direct interaction with members of the Wiskott-Alrich Syndrome Protein (WASP) family which stimulates structures such as lamellipodia and filopodia. The present review explores the role and function of Rho GTPases, WASP and WAVE in cancer metastasis.
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Affiliation(s)
- Jane Lane
- Cardiff University-Peking University Cancer Institute, Henry Wellcome Building, Cardiff University School of Medicine, Heath Park, Cardiff, U.K
| | - Tracey Martin
- Cardiff University-Peking University Cancer Institute, Henry Wellcome Building, Cardiff University School of Medicine, Heath Park, Cardiff, U.K
| | - Hoi Ping Weeks
- Cardiff University-Peking University Cancer Institute, Henry Wellcome Building, Cardiff University School of Medicine, Heath Park, Cardiff, U.K
| | - Wen Guo Jiang
- Cardiff University-Peking University Cancer Institute, Henry Wellcome Building, Cardiff University School of Medicine, Heath Park, Cardiff, U.K
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27
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Wieland MB, Slater AG, Mangham B, Champness NR, Beton PH. Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films. Beilstein J Nanotechnol 2014; 5:394-401. [PMID: 24778965 PMCID: PMC3999765 DOI: 10.3762/bjnano.5.46] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 03/10/2014] [Indexed: 06/03/2023]
Abstract
We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS). This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins.
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Affiliation(s)
- Maria B Wieland
- School of Physics & Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Anna G Slater
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
- Present address: Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK
| | - Barry Mangham
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Neil R Champness
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter H Beton
- School of Physics & Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
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Hancock SL, Mahon MF, Jones MD. Monomeric Ti(IV) homopiperazine complexes and their exploitation for the ring opening polymerisation of rac-lactide. Chem Cent J 2013; 7:135. [PMID: 23915921 PMCID: PMC3750606 DOI: 10.1186/1752-153x-7-135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/29/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The area of biodegradable/sustainable polymers is one of increasing importance in the 21st Century due to their positive environmental characteristics. Lewis acidic metal centres are currently one of the most popular choices for the initiator for the polymerisation. Thus, in this paper we report the synthesis and characterisation of a series of monometallic homopiperazine Ti(IV) complexes where we have systematically varied the sterics of the phenol moieties. RESULTS When the ortho substituent of the ligand is either a Me, tBu or amyl then the β-cis isomer is isolated exclusively in the solid-state. Nevertheless, in solution multiple isomers are clearly observed from analysis of the NMR spectra. However, when the ortho substituent is an H-atom then the trans-isomer is formed in the solid-state and solely in solution. The complexes have been screened for the polymerisation of rac-lactide in solution and under the industrially preferred melt conditions. Narrow molecular weight material (PDI 1.07 - 1.23) is formed under melt conditions with controlled molecular weights. CONCLUSIONS Six new Ti(IV) complexes are presented which are highly active for the polymerisation. In all cases atactic polymer is prepared with predictable molecular weight control. This shows the potential applicability of Ti(IV) to initiate the polymerisations.
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Affiliation(s)
- Stuart L Hancock
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Mary F Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Matthew D Jones
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Mpiana PT, Ngbolua KNN, Bokota MT, Kasonga TK, Atibu EK, Tshibangu DST, Mudogo V. In vitro effects of anthocyanin extracts from Justicia secunda Vahl on the solubility of haemoglobin S and membrane stability of sickle erythrocytes. Blood Transfus 2010; 8:248-54. [PMID: 20967165 PMCID: PMC2957489 DOI: 10.2450/2009.0120-09] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 09/02/2009] [Indexed: 11/21/2022]
Abstract
BACKGROUND Sickle cell disease or drepanocytosis is caused by the polymerisation of abnormal haemoglobin S when oxygen tension decreases. This lead to the changes in the shape of red blood cells and anaemia. It has also been postulated that the red cells of patients with sickle cell disease contain a higher than normal concentration of calcium ions. These ions are bound to membrane proteins resulting in dehydration and loss of red blood cell deformability and cell-to-cell adherence. Anthocyanins extracted from some Congolese plants used in traditional medicine against sickle cell disease have recently been shown to have anti-sickling activity in vitro. Justicia secunda is a plant used in Congo by Jehovah's Witnesses, well known for their refusal of blood transfusions, against anaemia. MATERIALS AND METHODS Emmel, Itano and osmotic fragility tests were used to test the effect of anthocyanin extracts from Justicia secunda leaves on haemoglobin S solubility and sickle cell membrane stability. RESULTS Anthocyanins from Justicia secunda were found to possess anti-sickling activity. Treated SS red blood cells recovered a normal, classical biconcave form with a radius of 3.3±0.3 μm, similar to that of normal erythrocytes. The solubility of deoxyhaemoglobin S increased and the osmotic fragility of drepanocytes decreased upon treatment with anthocyanin extracts. CONCLUSION These findings suggest that anthocyanin extracts play a role in both stabilising the red blood cell membrane and inhibiting polymerisation of haemoglobin S. This provides a possible molecular basis for earlier reports on the anti-sickling properties of anthocyanins from some Congolese plants and their use in the management of sickle cell disease by Congolese traditional healers.
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Affiliation(s)
- Pius T. Mpiana
- Department of Chemistry, Faculty of Sciences B.P. 190, University of Kinshasa, Kinshasa XI
| | | | - Matthieu T. Bokota
- Department of Chemistry, Faculty of Sciences, University of Kisangani, Kisangani
| | - Teddy K. Kasonga
- Department of Biology and Applied Techniques, Gombe Teaching Institute, Kinshasa, D.R.Congo
| | - Emmanuel K. Atibu
- Department of Chemistry, Faculty of Sciences B.P. 190, University of Kinshasa, Kinshasa XI
| | - Damien S. T. Tshibangu
- Department of Chemistry, Faculty of Sciences B.P. 190, University of Kinshasa, Kinshasa XI
| | - Virima Mudogo
- Department of Chemistry, Faculty of Sciences B.P. 190, University of Kinshasa, Kinshasa XI
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Gooptu B, Miranda E, Nobeli I, Mallya M, Purkiss A, Brown SCL, Summers C, Phillips RL, Lomas DA, Barrett TE. Crystallographic and cellular characterisation of two mechanisms stabilising the native fold of alpha1-antitrypsin: implications for disease and drug design. J Mol Biol 2009; 387:857-68. [PMID: 19232354 PMCID: PMC2723994 DOI: 10.1016/j.jmb.2009.01.069] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 01/31/2009] [Indexed: 11/28/2022]
Abstract
The common Z mutant (Glu342Lys) of alpha(1)-antitrypsin results in the formation of polymers that are retained within hepatocytes. This causes liver disease whilst the plasma deficiency of an important proteinase inhibitor predisposes to emphysema. The Thr114Phe and Gly117Phe mutations border a surface cavity identified as a target for rational drug design. These mutations preserve inhibitory activity but reduce the polymerisation of wild-type native alpha(1)-antitrypsin in vitro and increase secretion in a Xenopus oocyte model of disease. To understand these effects, we have crystallised both mutants and solved their structures. The 2.2 A structure of Thr114Phe alpha(1)-antitrypsin demonstrates that the effects of the mutation are mediated entirely by well-defined partial cavity blockade and allows in silico screening of fragments capable of mimicking the effects of the mutation. The Gly117Phe mutation operates differently, repacking aromatic side chains in the helix F-beta-sheet A interface to induce a half-turn downward shift of the adjacent F helix. We have further characterised the effects of these two mutations in combination with the Z mutation in a eukaryotic cell model of disease. Both mutations increase the secretion of Z alpha(1)-antitrypsin in the native conformation, but the double mutants remain more polymerogenic than the wild-type (M) protein. Taken together, these data support different mechanisms by which the Thr114Phe and Gly117Phe mutations stabilise the native fold of alpha(1)-antitrypsin and increase secretion of monomeric protein in cell models of disease.
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Affiliation(s)
- Bibek Gooptu
- School of Crystallography, Birkbeck College, University of London, London, UK.
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Abstract
Point mutations in members of the serine proteinase inhibitor or serpin superfamily cause them to change shape, polymerise and be deposited in the tissues. This process is best seen in mutants of alpha1-antitrypsin within hepatocytes to cause periodic acid-Schiff (PAS) positive inclusions and cirrhosis. An identical process underlies the PAS positive inclusions of mutants of neuroserpin within neurones to cause a dementia that we have called familial encephalopathy with neuroserpin inclusion bodies (FENIB). In both cases, there is a direct correlation between the molecular instability, the rate of intracellular polymer formation and the severity of disease. This process of polymerisation also explains the failure to secrete mutants of other members of the serpin superfamily--antithrombin, C1 inhibitor and alpha1-antichymotrypsin--to cause thrombosis, angio-oedema and emphysema, respectively. In view of the common mechanism underlying these conditions, we have grouped them together as the serpinopathies.
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Affiliation(s)
- David A Lomas
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research.
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