Design Rules for Enhanced Interfacial Shear Response in Functionalized Carbon Fiber Epoxy Composites

Carbon-fiber reinforced composites are ideal light-weighting candidates to replace traditional engineering materials. The mechanical performance of these composites results from a complex interplay of influences operating over several length and time scales. The mechanical performance may therefore be limited by many factors, one of which being the modest interfacial adhesion between the carbon fiber and the polymer. Chemical modification of the fiber, via surface grafting of molecules, is one possible strategy to enhance interactions across the fiber-polymer interface. To achieve systematic improvements in these modified materials, the ability to manipulate and monitor the molecular structure of the polymer interphase and the surface grafted molecules in the composite is essential, but challenging to accomplish from a purely experimental perspective. Alternatively, molecular simulations can bridge this knowledge gap by providing molecular-scale insights into the optimal design of these surface-grafted molecules to deliver superior mechanical properties. Here we use molecular dynamics simulations to predict the interfacial shear response of a typical epoxy/carbon-fiber composite for both pristine fiber and a range of surface graftings. We allow for the dynamic curing of the epoxy in the presence of the functionalized surface, including cross-link formation between the grafted molecules and the polymer matrix. Our predictions agree with recently reported experimental data for these systems and reveal the molecular-scale origins of the enhanced interfacial shear response arising from functionalization. In addition to the presence of interfacial covalent bonds, we find that the interfacial structural complexity, resulting from the presence of the grafted molecules, and a concomitant spatial homogeneity of the interphase polymer density are beneficial factors in conferring high interfacial shear stress. Our approach paves the way for computational screening processes to design, test, and rapidly identify viable surface modifications in silico, which would enable rapid systematic progress in optimizing the match between the carbon fiber treatment and the desired thermoset polymer matrix.

Angular deformity development after the distal tibial physeal fractures

Several clinical and radiological factors can be prognostic in the development of angular deformity following physeal injuries of the distal tibia. One of the radiological parameters, premature physeal closure (PPC), can be detected during postoperative follow-ups. Aim of our study was to identify the prognostic factors in development of angular deformity and its relationship with PPC. One hundred and four patients treated due to physeal injuries of the distal tibia were included in our study. Patients were divided into three groups based on Salter-Harris (SH) classification. The intergroup relationships between sex, age, the amount of energy sustained during injury, premature physeal closure, the amount of residual gap, and deformity were analyzed. Angular deformity developed in 25% (3/12) of SH Type 2, in 60% (9/15) of Type 3 and 30% (3/10) of Type 4 patients with PPC. A residual displacement of more than 2 mm, age and premature physeal closure were specified as significant risk factors for development of angular deformity. 2 mm limit for residual displacement and findings of premature physeal closure in the radiological evaluations during follow-ups are prognostic factors in avoiding malalignment of the distal tibia.

LEVEL OF EVIDENCE

Level 3.

Correction: Determination of Kamlet-Taft parameters for selected solvate ionic liquids

Correction for 'Determination of Kamlet-Taft parameters for selected solvate ionic liquids' by Daniel J. Eyckens et al., Phys. Chem. Chem. Phys., 2016, 18, 13153-13157.

A robust and reproducible procedure for cross-linking thermoset polymers using molecular simulation

Molecular simulation can provide valuable guidance in establishing clear links between structure and function to enable the design of new polymer-based materials. However, molecular simulation of thermoset polymers in particular, such as epoxies, present specific challenges, chiefly in the credible preparation of polymerised samples. Despite this need, a comprehensive, reproducible and robust process for accomplishing this using molecular simulation is still lacking. Here, we introduce a clear and reproducible cross-linking protocol to reliably generate three dimensional epoxy cross-linked polymer structures for use in molecular simulations. This protocol is sufficiently detailed to allow complete reproduction of our results, and is applicable to any general thermoset polymer. Amongst our developments, key features include a reproducible procedure for calculation of partial atomic charges, a reliable process for generating and validating an equilibrated liquid precursor mixture, and establishment of a novel, robust and reproducible protocol for generating the three-dimensional cross-linked solid polymer. We use these structures as input to subsequent molecular dynamics simulations to calculate a range thermo-mechanical properties, which compare favourably with experimental data. Our general protocol provides a benchmark for the process of simulating epoxy polymers, and can be readily translated to prepare and model epoxy samples that are dynamically cross-linked in the presence of surfaces and nanostructures.

Reproductive performance after hysteroscopic metroplasty in infertile women: complete versus partial uterine septum

OBJECTIVE

To investigate the impact of hysteroscopic metroplasty on pregnancy outcome in women with complete or incomplete uterine septum (US) accompanying infertility.

MATERIALS AND METHODS

Seventy-three patients who had hysteroscopic metroplasty for complete and incomplete US with primary and secondary infertility were reviewed. Obstetric outcomes (number of pregnancies, live births, and miscarriages) up to 36 months follow up period were investigated.

RESULTS

Twenty-five patients in complete US and 28 patients in incomplete US became pregnant in 36 months follow up. Postoperative miscarriage rate was significantly lower in patients with complete US (p = 0.0001,p = 0.0001, respectively). The mean gestational week at the time of birth and mean birth weight of the in- fants were significantly lower in patients with complete US compared to the incomplete US cases (p = 0.026, p = 0.049, respectively). Postoperative pregnancy rate was significantly lower in incomplete US patients with primary infertility compared with secondary in- fertility (p = 0.037).

CONCLUSION

Hysteroscopic metroplasty improves fertility and pregnancy performance. This improvement is more prominent in patients with complete US, and incomplete US patients with secondary infertility.

Determination of Kamlet–Taft parameters for selected solvate ionic liquids

The normalised polarity ENT and Kamlet–Taft parameters of recently described solvate ionic liquids, composed of lithium bis(trifluoromethyl)sulfonimide (LiTFSI) in tri- (G3TFSI) or tetraglyme (G4TFSI) have been determined and compared to the parent glyme (G3 and G4).

Production cross–section calculations of medical 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment

In this study, production cross–section calculations of 32P, 117Sn, 153Sm and 186,188Re radionuclides used in bone pain palliation treatment produced by 30Si(d,γ)32P, 118Sn(γ,n)117Sn, 116Sn(n,γ)117Sn, 150Nd(α,n)153Sm, 154Sm(n,2n)153Sm, 152Sm(n,γ)153Sm, 186W(d,2n)186Re, 187Re(γ,n)186Re, 185Re(n,γ)186Re and 187Re(n,γ)188Re reactions have been investigated in the different incident energy range of 0.003–34 MeV. Two-component exciton and generalised superfluid models of the TALYS 1.6 and exciton and generalised superfluid models of the EMPIRE 3.1 computer codes have been used to pre-equilibrium (PEQ) reaction calculations. The calculated production cross–section results have been compared with available experimental results existing in the experimental nuclear reaction database (EXFOR). Except the 118Sn(γ,n)117Sn, 150Nd(α,n)153Sm and 185Re(n,γ)186Re reactions, the two-component exciton model calculations of TALYS 1.6 code exhibit generally good agreement with the experimental measurements for all reactions used in this present study.

Reattachment of dehydrated tooth fragments: two case reports

Anterior crown fractures are the most common type of injury in dental trauma. The ideal treatment is to reattach the fragments as quickly as possible following intraoral and radiographic examination, but sometimes delayed treatment appointments are necessary because of uninformed patients/parents or multidisciplinary cases included endodontically and periodontically. Delayed reattachment may lead to unesthetic results because of the dehydration of fragments. The purpose of this study was to present 1-year follow-ups of reattachment of dehydrated fragments using dentin bondings and flowable composites in two different cases. The color of the dehydrated fragments was natural in the control appointments and 1-year follow-ups show harmonious integration of color, form and texture after the reattachment of the original piece of tooth. Restoration of the tooth by reattaching the original fragment is the best way of treatment in esthetic, conservative and economic point of view.

A multi-functional fluorescent scaffold as a multi-colour probe: design and application in targeted cell imaging

A new scaffold material based on a novel targeting strategy has been developed, benefiting from recent progress in the development of tailor-made fluorescent bioprobes for cellular imaging and opening a new viewpoint for further improvements in in vitro and in vivo imaging.

The relationship between ischemia modified albumin and oxidative stress parameters in patients with cardiac syndrome X

BACKGROUND

The objective of this study was to evaluate the serum levels of ischemia modified albumin and oxidative stress parameters in patients with cardiac syndrome X.

METHODS

A total of 61 patients, composed of 32 consecutive patients (24 female, 8 male, average age: 47.63 +/- 9.49 years) diagnosed with cardiac syndrome X by coronary angiography (initially performed following the identification of ischemia by exercise stress test or myocardial perfusion scintigraphy) and a control group of 29 consecutive patients (15 female, 14 male, average age: 49.59 +/- 11.68 years) with similar features without cardiac syndrome X were included in the study. The levels of the ischemia modified albumin (IMA), ferric reducing antioxidant power (FRAP), prooxidant-antioxidant balance (PAB), and advanced protein oxidation products (AOPP) were determined by colorimetric methods.

RESULTS

Patients have significantly higher PAB, AOPP, and IMA levels in the patient group than in the control group (p < 0.01, p < 0.001, and p < 0.02, respectively). Also, serum triglyceride (p < 0.005) and hs-CRP (p < 0.0001) levels were significantly higher in the patient group (p < 0.01, p < 0.001, and p < 0.02, respectively). We found that there was a significant correlation between hs-CRP, plasma PAB (r: 0.258; p < 0.05), AOPP (r: 0.459; p < 0.001), and triglyceride levels (r: 0.404; p < 0.01). Plasma AOPP levels were also significantly positive correlated with triglyceride levels (r: 0.463; p < 0.001). In addition, during the correlation analysis performed on the patient group, a positive correlation was observed between the levels of IMA with the levels of plasma PAB and plasma AOPP (r: 0,994; p < 0.01 and r: 0.857; p < 0.05, respectively) In a multiple linear regression analysis, AOPP levels were significantly related with hs-CRP and triglyceride (R2: 0.380, p < 0.0001 and p < 0.05). Simple linear regression analysis was performed between plasma PAB (as dependent variable) and hs-CRP levels. Plasma PAB levels were related with hs-CRP (R2: 0.258, p < 0.05). Using the receiver-operator characteristic (ROC) curve, the best cut-off values for predicting cardiac syndrome X of PAD, AOPP, IMA, and hs-CRP levels were 88.1 arbitrary units, 68.5 kloramin T micromol/L, 7.17 U/mL, and 1.09 mg/dL, respectively.

CONCLUSIONS

Based on the results of our study, the increase in oxidative stress during cardiac syndrome X appears to be related to elevated levels of IMA. Treatment modalities that decrease oxidative stress might be beneficial for the treatment of cardiac syndrome X.

Gold nanoparticle loaded phytosomal systems: synthesis, characterization and in vitro investigations

A novel liposomal formulation was synthesized by encapsulating both gold nanoparticles (AuNPs) andCalendula officinalisextract as AuNP-phytosomes and AuNP-phytosomes were characterized and used atin vitroinvestigations.

Folic acid modified clay/polymer nanocomposites for selective cell adhesion

A promising material, a folic acid modified poly(epsilon-caprolactone)/clay nanocomposite that allows selective cell adhesion and proliferation, was synthesized and characterized as a cell culture and biosensing platform.

Correlation of myocardial performance index assessed by different echocardiographic methods in patients with acute myocard infarction receiving different reperfusion treatment

AIM

Myocardial performance index (MPI) is a well known prognostic parameter in acute myocardial infarction (AMI) patients, which has been used to assess global cardiac functions. In this study, we aimed to evaluate the corelation between the MPI levels obtained by PW doppler and Tissue doppler ultrasonography with reperfusion in AMI patients.

METHODS

Fifty-four consecutive acute ST elevatation myocardial infarction patients, 26 treated with primary percutaneous coronary intervention (PCI) and 28 with thrombolytic therapy (TT); and 15 consecutive healthy controls were included in the study. MPI levels were measured with pulsed-wave (PW) doppler and tissue Doppler ultrasonography in all patients. The isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT) and ejection time (ET) values used to measure MPI levels were determined. Corelation between the time intervals obtained with both methods were evaluated. MPI variations were evaluated in patients treated with PCI and TT. A significant corelation was observed in MPI levels obtained with PW doppler and tissue doppler ultrasonography (P<0.001) as well as between IRT, ICT and ET values (for all parameters; P<0.001). No significant corelation was observed between the MPI levels obtained with PW doppler and tissue doppler ultrasonography in patients treated with primary PTCA and TT (P=0.128, P=0.991, respectively). A significant corelation was observed between the MPI values obtained by PW doppler and tissue doppler ultrasonography with reperfusion interval (P=0.002, P<0.001, respectively).

CONCLUSION

As a result, tissue Doppler ultrasonography may be used as an alternative to PW doppler to evaluate MPI, which is a well known prognostic factor in AMI. No relation has been observed between MPI values in early phases of AMI with reperfusion pattern, while a connection has been observed between MPI and reperfusion interval.