scholarly journals Design & development of a novel glass polyalkenoate cement for sternal fixation and repair, in the event of median sternotomy surgery

2021 ◽  
Author(s):  
Adel M.F. Alhalawani
Keyword(s):  
Glass Structure ◽  
Open Heart Surgery ◽  
Median Sternotomy ◽  
Magic Angle Spinning ◽  
Size Analysis ◽  
Wound Complications ◽  
Magic Angle ◽  
X Ray ◽  
Sternal Closure ◽  
Mole Percentage

Median sternotomy surgery is the gold standard for cardiac/thoracic procedures such as open-heart surgery. With over one million median sternotomy surgeries performed worldwide every year, sternal wound complications pose a serious risk to the health of affected patients. Various techniques have been used for sternal fixation including wiring, plate-screw systems and cementing. The ideal sternal closure device is the one which has mechanical properties suited to the local environment, biocompatibility, radio-opacity, cost-effectiveness and ease of removal when necessary. None of the techniques that have been utilized for sternal fixation to date address all of these requirements. Glass polyalkenoate cements (GPCs) have a long history of use in restorative and orthodontic dentistry and ear, nose and throat (ENT) surgery but have yet to be indicated for musculoskeletal applications. This dissertation relates to the development of new GPC-based adhesives for use in sternal closure. A series of novel glasses based on the system 48SiO2-(36-X) ZnO-6CaO-8SrO-2P2O5-XTa2O5 with X varying from 0.0 to 8.0 mole percentage were fabricated and characterized. The structural features as a function of Ta2O5 content were investigated by network connectivity (NC) calculations, x-ray diffraction (XRD), particle size analysis (PSA), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and magic angle spinning-nuclear magnetic resonance (MAS-NMR). The thermal properties of the glasses were obtained by performing simultaneous thermal analysis (STA). The effect of glass structure on pH and solubility was also evaluated. The formulated glasses were used to prepare GPC adhesive materials and tested for their suitability for sternal fixation. The data collected has confirmed that substituting up to 0.5 mole percentage of ZnO with Ta2O5 in the glass system under study resulted in the formation of adhesives that are deemed suitable for sternal fixation. The formulated cements, based on the use of glasses containing no greater than 0.5 mole percentage of Ta2O5 have rheology, strength, radiopacity, antibacterial and in-vitro behavior suitable for sternal fixation. To the best knowledge of the candidate, this dissertation is the first to report the use of tantalum-containing GPC-based adhesives for sternal closure. Based on the obtained results, the formulated adhesives can be used in conjunction with sternal cable ties (current standard method) to offer optimal fixation for patients and reduce post-operative complications such as bacterial infection and pain from micro-motion.

scholarly journals Design & development of a novel glass polyalkenoate cement for sternal fixation and repair, in the event of median sternotomy surgery

2021 ◽  
Author(s):  
Adel M.F. Alhalawani
Keyword(s):  
Glass Structure ◽  
Open Heart Surgery ◽  
Median Sternotomy ◽  
Magic Angle Spinning ◽  
Size Analysis ◽  
Wound Complications ◽  
Magic Angle ◽  
X Ray ◽  
Sternal Closure ◽  
Mole Percentage

Median sternotomy surgery is the gold standard for cardiac/thoracic procedures such as open-heart surgery. With over one million median sternotomy surgeries performed worldwide every year, sternal wound complications pose a serious risk to the health of affected patients. Various techniques have been used for sternal fixation including wiring, plate-screw systems and cementing. The ideal sternal closure device is the one which has mechanical properties suited to the local environment, biocompatibility, radio-opacity, cost-effectiveness and ease of removal when necessary. None of the techniques that have been utilized for sternal fixation to date address all of these requirements. Glass polyalkenoate cements (GPCs) have a long history of use in restorative and orthodontic dentistry and ear, nose and throat (ENT) surgery but have yet to be indicated for musculoskeletal applications. This dissertation relates to the development of new GPC-based adhesives for use in sternal closure. A series of novel glasses based on the system 48SiO2-(36-X) ZnO-6CaO-8SrO-2P2O5-XTa2O5 with X varying from 0.0 to 8.0 mole percentage were fabricated and characterized. The structural features as a function of Ta2O5 content were investigated by network connectivity (NC) calculations, x-ray diffraction (XRD), particle size analysis (PSA), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and magic angle spinning-nuclear magnetic resonance (MAS-NMR). The thermal properties of the glasses were obtained by performing simultaneous thermal analysis (STA). The effect of glass structure on pH and solubility was also evaluated. The formulated glasses were used to prepare GPC adhesive materials and tested for their suitability for sternal fixation. The data collected has confirmed that substituting up to 0.5 mole percentage of ZnO with Ta2O5 in the glass system under study resulted in the formation of adhesives that are deemed suitable for sternal fixation. The formulated cements, based on the use of glasses containing no greater than 0.5 mole percentage of Ta2O5 have rheology, strength, radiopacity, antibacterial and in-vitro behavior suitable for sternal fixation. To the best knowledge of the candidate, this dissertation is the first to report the use of tantalum-containing GPC-based adhesives for sternal closure. Based on the obtained results, the formulated adhesives can be used in conjunction with sternal cable ties (current standard method) to offer optimal fixation for patients and reduce post-operative complications such as bacterial infection and pain from micro-motion.

scholarly journals OUTCOMES AND SAFETY OF STERNAL CLOSURE USING NON-ABSORBABLE POLYESTER BRAIDED SUTURE: SINGLE TERTIARY CARE CENTER EXPERIENCE OF 5 YEARS.

2020 ◽  
pp. 1-3
Author(s):  
Manpal Loona ◽  
Rahul Bhushan ◽  
Vaibhav chugh ◽  
Narender S. Jhajhria ◽  
Vijay Grover ◽  
...  
Keyword(s):  
Heart Surgery ◽  
Care Center ◽  
Tertiary Care ◽  
Open Heart Surgery ◽  
Median Sternotomy ◽  
Wound Complications ◽  
Sternal Dehiscence ◽  
Sternal Closure ◽  
Surgical Suture ◽  
Poly Ethylene

Introduction: Median sternotomy is done as regular practice in cardiac surgery, which can lead to morbidity and mortality after sternal closure. Inappropriate sternal closure can lead to sternal dehiscence, sternal wound infection and mediastinitis. Aim: Efficacy and outcomes of sternal closure in adults weighing 2.5 kgs to 50 kgs using non-absorbable polyester braided suture. Methods: Total of 1091 patients underwent standard median sternotomy, weighing between 2.5 kgs to 50 kgs had sternal closure using non absorbable, braided, sterile, surgical suture composed of Poly ethylene terephthalate [polyester]. A retrospective analysis was done to review outcomes and complications related to this sternal closure technique. Results: Nineteen patients developed superficial surgical site infection and sternal sinus were seen in eight patients, whereas one patient had sternal dehiscence during immediate post-operative period. No sternal sutures were broken during the sternal closure and no case of mediastinitis was seen. Follow-up analyses of patients were done for 6 months after open heart surgery. Conclusion: Sternal closure using non-absorbable polyester braided suture is a safe and effective method with very less chances of post sternal wound complications in patients weighing between 2.5 kgs to 50 kgs.

A 13C and 15N nuclear magnetic resonance study of solid ammonium thiocyanate

1987 ◽  
Vol 65 (5) ◽  
pp. 941-946 ◽  
Author(s):  
Ross M. Dickson ◽  
Michael S. McKinnon ◽  
James F. Britten ◽  
Roderick E. Wasylishen
Keyword(s):  
Ammonium Thiocyanate ◽  
Nuclear Magnetic Resonance Study ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
X Ray ◽  
Shielding Constants ◽  
Angle Spinning ◽  
Good Agreement ◽  
C Nmr

The static 13C nmr powder pattern for solid ammonium thiocyanate is analyzed to obtain the 13C chemical shielding anisotropy, 321 ± 7 ppm, and the 13C–14N dipolar splitting, 1295 ± 25 Hz. Slow magic angle spinning 15N nmr experiments are analyzed to obtain a nitrogen chemical shielding anisotropy of 415 ± 15 ppm. The 13C–14N dipolar splitting leads to an effective C—N bond length of 1.19 ± 0.01 Å, in good agreement with the value of 1.176 Å reported from accurate X-ray and neutron crystallographic studies. In solid NH4NCS absolute values of the average shielding constants [Formula: see text] and ct[Formula: see text] are 52 and 34 ppm, respectively. Comparison of calculated and observed [Formula: see text] values indicates that intermolecular interactions decrease the 13C and 15N shielding constants by approximately 10 and 30 ppm, respectively.

scholarly journals High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

2015 ◽  
Vol 112 (46) ◽  
pp. 14156-14161 ◽  
Author(s):  
Seung Bin Baek ◽  
Dohyun Moon ◽  
Robert Graf ◽  
Woo Jong Cho ◽  
Sung Woo Park ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Direct Detection ◽  
Variable Temperature ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dynamic Motion

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use.

scholarly journals Arene guest selectivity and pore flexibility in a metal–organic framework with semi-fluorinated channel walls

2017 ◽  
Vol 375 (2084) ◽  
pp. 20160031 ◽  
Author(s):  
Rebecca Smith ◽  
Iñigo J. Vitórica-Yrezábal ◽  
Adrian Hill ◽  
Lee Brammer
Keyword(s):  
Nmr Spectroscopy ◽  
Metal Organic Framework ◽  
Magic Angle Spinning ◽  
Nitrogen Atmosphere ◽  
Magic Angle ◽  
Ambient Conditions ◽  
Solid State Transformation ◽  
X Ray ◽  
Metal Organic ◽  
Organic Framework

A metal–organic framework (MOF) with one-dimensional channels of approximately hexagonal cross-section [Ag 2 (O 2 CCF 2 CF 2 CO 2 )(TMP)] 1 (TMP =2,3,5,6-tetramethylpyrazine) has been synthesized with MeOH filling the channels in its as-synthesized form as [Ag 2 (O 2 CCF 2 CF 2 CO 2 )(TMP)]· n (MeOH) 1-MeOH ( n  = 1.625 by X-ray crystallography). The two types of ligand connect columns of Ag(I) centres in an alternating manner, both around the channels and along their length, leading to an alternating arrangement of hydrocarbon (C–H) and fluorocarbon (C–F) groups lining the channel walls, with the former groups projecting further into the channel than the latter. MeOH solvent in the channels can be exchanged for a variety of arene guests, ranging from xylenes to tetrafluorobenzene, as confirmed by gas chromatography, 1 H nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis and 13 C cross-polarization magic angle spinning NMR spectroscopy. Alkane and perfluoroalkane guests, however, do not enter the channels. Although exhibiting some stability under a nitrogen atmosphere, sufficient to enable crystal structure determination, the evacuated MOF 1 is unstable for periods of more than minutes under ambient conditions or upon heating, whereupon it undergoes an irreversible solid-state transformation to a non-porous polymorph 2 , which comprises Ag 2 (O 2 CCF 2 CF 2 CO 2 ) coordination layers that are pillared by TMP ligands. This transformation has been followed in situ by powder X-ray diffraction and shown to proceed via a crystalline intermediate. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.

Structural Properties of a Dimeric Phenylcyanamidocopper(I) Complex, [{Cu(PPh3)2(C6H5NCN)}2]

2000 ◽  
Vol 53 (12) ◽  
pp. 971 ◽  
Author(s):  
Eric W. Ainscough ◽  
Andrew M. Brodie ◽  
Peter C. Healy ◽  
Joyce M. Waters
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Structural Properties ◽  
Structure Determination ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
X Ray ◽  
Angle Spinning

The X-ray crystal structure determination of bis[-(phenylcyanamido)bis(triphenylphosphine)copper(I)], [{Cu(PPh3)2(C6H5NCN)}2], (1) is reported. The complex has a centrosymmetric dimeric structure with the phenylcyanamide ligands bridging the copper atoms in a -1,3-fashion. The structure is compared with that of the 4-methylphenylcyanamido complex, [{Cu(PPh3)2(4-MeC6H4NCN)}2] (2), and the differences observed in the Cu–P bond lengths compared with changes in the solid state 31P cross-polarization magic-angle spinning (CPMAS) spectra of the two complexes.

The crystal chemistry of rhodizite: a re-examination

1986 ◽  
Vol 50 (355) ◽  
pp. 163-172 ◽  
Author(s):  
A. Pring ◽  
V. K. Din ◽  
D. A. Jefferson ◽  
J. M. Thomas
Keyword(s):  
Single Crystal ◽  
Crystal Chemistry ◽  
Structure Refinement ◽  
High Resolution Electron Microscopy ◽  
Basic Structure ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Alkali Cations ◽  
X Ray ◽  
Using Data

AbstractThe crystal chemistry of rhodizite was re-examined using data from high-resolution electron microscopy (HREM), magic angle spinning nuclear magnetic resonance (MASNMR), a single crystal X-ray structure refinement, and a new chemical analysis. The analysis calculates to the formula: (K0.46Cs0.36Rb0.06 Na0.02)Σ0.90Al3.99Be4(B11·35Be0.55Li0.02)O28· The distribution of alkali cations was shown to be truly random by HREM images and computer image simulations. The distribution of boron and beryllium was monitored by MASNMR, the spectra for both elements gave only single resonances indicating that all beryllium and boron atoms are located in chemically equivalent sites. The structure of rhodizite was refined by single crystal X-ray diffraction techniques. The mineral is cubic a = 7.318(1) Å, space group P3. A full matrix least-squares refinement using 152 unique observed reflections [F > 3σ(F)] converged to R = 0.0344. The refinement confirmed the basic structure as determined by Taxer and Buerger (1967), 4 beryllium atoms of the unit cell were found to occupy a 4e special position, the remaining 0.5 being randomly distributed with the 11.35 boron atoms over the 12h sites.

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