The Influence of Indirect Bonding Technique on Adhesion of Orthodontic Brackets and Post-Debonding Enamel Integrity-An In Vitro Study

The increasing demand for orthodontic treatments due to the high prevalence of malocclusion has inspired clinicians and material scientists to investigate innovative, more effective, and precise bonding methods with reduced chairside time. This study aimed at comparing the shear bond strength (SBS) of metal and ceramic brackets bonded to enamel using the indirect bonding technique (IDB). Victory Series metal brackets (Metal-OPC, Metal-APC) and Clarity™ Advanced ceramic brackets (Ceramic-OPC) (3M Unitek, Monrovia, CA, USA) were bonded indirectly to extracted human premolars through the etch-and-rinse technique. A qualitative assessment of the enamel surface using microscopic methods was performed, and the amount of residual adhesive was reported as per the adhesive remnant index (ARI). Moreover, the bracket surface was evaluated with SEM-EDS. The highest SBS mean values were observed in the Ceramic-OPC group (16.33 ± 2.01 MPa), while the lowest ones were obtained with the Metal-OPC group (11.51 ± 1.40 MPa). The differences between the Metal-AOPC vs. Metal-APC groups (p = 0.0002) and the Metal-OPC vs. Ceramic-OPC groups (p = 0.0000) were statistically significant. Although the Ceramic-OPC brackets bonded indirectly to the enamel surface achieved the highest SBS, the enamel damage was significantly higher compared to that of the other groups. Thus, considering the relatively high bond SBS and favourable debonding pattern, Metal-APC brackets bonded indirectly may represent the best choice.

Shear Bond Strength of Metal and Ceramic Brackets Depending on Etching Protocol in Direct Bonding Technique

Successful orthodontic therapy, apart from a proper treatment plan, depends on optimal bracket-enamel adhesion. Among numerous factors affecting adhesion, the type of bracket and preparation of the tooth's surface are crucial. The aim of this study was to compare the shear bond strength (SBS) of metal and ceramic brackets to the enamel's surface using direct bonding. Forty extracted human premolars were divided into four groups according to the etching method (etch-and-rinse and self-etch) and bracket type. The SBS and adhesive remnant index (ARI) were determined. The ceramic brackets achieved the highest SBS values both in the self-etch (SE) and etch-and-rinse (ER) protocols. Higher SBS values for ceramic and metallic brackets were found in the ER protocol. In all tested groups, the achieved SBS value was satisfactory to withstand orthodontic and occlusal forces. There was no significant difference in the ARI score between study groups (p = 0.71). The fracture occurred between the bracket base and adhesive material in both types of brackets, which decreased the risk of enamel damage during debonding.

Systematic Comparison of Ligament Reconstruction With Tendon Interposition and Suture-Button Suspensionplasty for Trapeziometacarpal Osteoarthritis

Ligament reconstruction tendon interposition (LRTI) and suture-button suspensionplasty (SBS) are both common treatment options for trapeziometacarpal osteoarthritis. The primary purpose of this systematic review was to compare the subjective improvement in patient-reported outcomes in regard to disability for patients undergoing LRTI and SBS for trapeziometacarpal osteoarthritis. A secondary purpose was to compare the subjective improvement, objective outcome scores, and complication rates following both procedures. We performed a systematic review using PubMed, Scopus, and Embase to compare the clinical outcomes of LRTI and SBS. Inclusion criteria were level I-IV evidence articles reporting postoperative Disabilities of the Arm, Shoulder, and Hand (DASH) or QuickDASH scores. Study methodological quality, risk of bias, and recommendation strength were assessed. This systematic review included 31 studies for final analysis with 1289 thumbs undergoing LRTI (25 studies) and 113 thumbs undergoing SBS (6 studies). Both procedures demonstrated similar improvement in DASH and/or QuickDASH scores, while key pinch and grip strength inconsistently improved following both procedures. Complication rate was similar between the 2 procedures; LRTI 12% and SBS 13%. Although both LRTI and SBS seem to provide improved short-term patient-reported functional improvement and objective strength, there was significant heterogeneity within the included studies, and those studies discussing SBS were of lower quality evidence than those of LRTI. Thus, to truly delineate whether a difference exists between these 2 techniques for the treatment of first carpometacarpal joint arthritis, larger prospectively designed studies of high-quality evidence are necessary.

Study on Thermal Stability and Fatigue Properties of SBS/CNT-Modified Asphalt Sealant

Carbon nanotubes (CNTs) and styrene-butadiene-styrene (SBS) are used as reinforcing modifiers in asphalt sealants due to their excellent properties, which can effectively improve the internal structure of the sealant and enhance its mechanical properties. Based on this background, two SBS/CNT-modified asphalt sealants were identified and selected by the orthogonal experimental method and compared with two commercially available sealants. The softening point, flow value, multi-temperature frequency scan test, and multiple stress creep recovery test were used to study the high-temperature rheological properties and aging resistance of four types of sealants. The overall evaluation shows that the proportion of the sealant compound's preparation material is 1% by weight of CNT doping, 5% by weight of SBS doping, and 5% by weight of furfural-extracted-oil doping. The results show that the addition of SBS and CNTs more significantly improves the fatigue resistance of the sealants. With the CAM model, C1.0S5F5 reflects a better relaxation property, which better avoids secondary cracking after the construction of the sealant. With the Burgers model, C1.0S5F5 shows excellent deformation resistance under heavy traffic conditions. In summary, conventional performance indicators, such as the softening point and flow value of SBS/CNT-modified asphalt sealants, can meet the specification requirements and show good high-temperature stability and anti-aging properties compared to commercially available sealants.

The Shear Bond Strength of Resin-Based Luting Cement to Zirconia Ceramics after Different Surface Treatments

Due to its unique properties, zirconia is increasingly being used in dentistry, but surface preparation for bonding is difficult because of its polycrystalline structure. This study aimed to determine the effect of a new etching technique (Zircos-E) on Ceramill Zi (Amann Girrbach). The effect of etching and the use of primers (Monobond Plus and MKZ Primer) on the bond strength of zirconia with resin cement (NX3) was assessed. Shear bond strength was evaluated after storage in water for 24 h and after thermal aging (5000 thermocycling at 5 °C/55 °C). A scanning electron microscope (Hitachi S-4700) was used to evaluate the surface structure before and after the Zircos-E system. The roughness parameters were assessed using an SJ-410 profilometer. The etched zirconia surface is more homogeneous over the entire surface, but some localized forms of erosion exist. The etching of zirconia ceramics caused changes in the surface structure of zirconia and a significant increase in the shear bond strength between zirconia and resin cement. The use of primers positively affects the adhesion between resin cement and zirconia. Aging with thermocycler significantly reduced the shear bond strength, with one exception-sandblasted samples with MKZ Primer. Standard ceramic surface preparation, involving only alumina sandblasting, does not provide a satisfactory bond. The use of etching with the Zircos-E system and primers had a positive effect on the strength of the zirconium-resin cement connection.

Expression, Purification and Characterization of Functional Teduglutide Using GST Fusion System in Prokaryotic Cells

Purpose

Teduglutide is the first and only FDA-approved drug for long-term treatment of short bowel syndrome (SBS). The current study aimed to present an approach for production of teduglutide using recombinant DNA technology.

Methods

The coding gene for teduglutide was cloned into pGEX-2T vector, where coding sequence for factor Xa cleavage site was added between GST and teduglutide coding genes. The GST-teduglutide protein was overexpressed in E. coli BL21 (DE3) strain and affinity purified using glutathione sepharose affinity column.

Results

On-column proteolytic activity of factor Xa followed by size exclusion chromatography resulted in the pure teduglutide. Circular dichroism (CD) spectropolarimetry showed that the produced teduglutide folds into mainly α-helical structure (>50%), as expected. In mass spectroscopy analysis, the fragments of teduglutide resulted by cyanogen bromide cleavage as well as those expected theoretically due to mass fragmentation were identified. The functionality of the produced peptide was evaluated by measuring its proliferative effect on Caco2 intestinal epithelial cells, and the results indicated that produced teduglutide induces cell proliferation by 19±0.30 and 33±7.82 % at 1.21 and 3.64 µM concentrations, respectively, compared to untreated cells.

Conclusion

Teduglutide was successfully expressed and purified and its functionality and structural integrity were confirmed by in vitro experiments. We believe that the experimental-scale method presented in the current study can be useful for pilot-scale and also industrial-scale production of teduglutide.

Durability of Polymer-Modified Asphalt Mixture with Wasted Tire Powder and Epoxy Resin under Tropical Climate Curing Conditions

The quality of pavements in tropical climates is negatively affected by the frequent wet and dry cycles during the rainy season, as well as by issues related to overloading from heavy trucks and traffic congestion. Contributing to this deterioration are factors such as acid rainwater, heavy traffic oils, and municipal debris. In light of these challenges, this study aims to assess the viability of a polymer-modified asphalt concrete mixture. This study investigates the feasibility of a polymer-modified asphalt concrete mixture with the addition of 6% crumb rubber powder from waste car tires and 3% epoxy resin to counter the harsh conditions of tropical climate weather. The study involved subjecting test specimens to five to 10 cycles of contaminated water (100% rainwater + 10% used oil from trucks), curing for 12 h, and air drying in a chamber of 50 °C for 12 h to simulate critical curing conditions. The specimens underwent fundamental laboratory performance tests such as the indirect tensile strength test, dynamic modulus test, four points bending test, and Cantabro test, as well as the double load condition in the Hamburg wheel tracking test to determine the effectiveness of the proposed polymer-modified material in actual conditions. The test results confirmed that the simulated curing cycles had a critical impact on the durability of the specimens, with the greater curing cycles leading to a significant drop in the strength of the material. For example, the TSR ratio of the control mixture dropped from 90% to 83% and 76% after five and 10 curing cycles, respectively. Meanwhile, the modified mixture showed a decrease from 93% to 88% and 85% under the same conditions. The test results revealed that the effectiveness of the modified mixture outperformed the conventional condition in all tests, with a more prominent impact observed under overload conditions. Under double conditions in the Hamburg wheel tracking test and a curing condition of 10 cycles, the maximum deformation of the control mixture sharply increased from 6.91 to 22.7 mm, whereas the modified mixture increased from 5.21 to 12.4 mm. Overall, the test results confirm the durability of the polymer-modified asphalt concrete mixture under harsh tropical climate conditions, promoting its application for sustainable pavements, especially in Southeast Asian countries.

Parental Knowledge and Awareness about Shaken Baby Syndrome in Jeddah, Saudi Arabia: A Cross-Sectional Study

BACKGROUND

Despite the serious consequences of shaken baby syndrome (SBS), previous studies revealed a low level of knowledge among Saudi parents.

METHODS

This is a cross-sectional study. An electronic questionnaire was distributed through social media platforms to parents of pediatric age group children in Jeddah, Saudi Arabia. A total of 524 responses were received. Data about participants' demographics, knowledge, attitude, and practice regarding SBS were collected through convenient random sampling.

RESULTS

A total of 524 responses were received; 30.7% of the participants were familiar with SBS. The Internet and the social media platforms were the most common sources of information. There was no statistically significant correlation between knowledge levels and participants' sociodemographic factors; only 32.3% of individuals had good knowledge. Of them, 84% had a positive attitude towards learning more about SBS, and 40.1% and 34.3% were interested in learning more about SBS before and during pregnancy, respectively. Carrying the baby and shaking were the actions most frequently taken when a baby was crying. Of them, 23.9% forcefully shake their child, while 41.4% of them throw their infant up in the air and catch it.

CONCLUSIONS

It is important to conduct health education programs on SBS for mothers throughout the prenatal period.

Vinylbenzyl Chloride/Styrene-Grafted SBS Copolymers via TEMPO-Mediated Polymerization for the Fabrication of Anion Exchange Membranes for Water Electrolysis

In this work, a commercial SBS was functionalized with the 2,2,6,6-tetramethylpiperidin-N-oxyl stable radical (TEMPO) via free-radical activation initiated with benzoyl peroxide (BPO). The obtained macroinitiator was used to graft both vinylbenzyl chloride (VBC) and styrene/VBC random copolymer chains from SBS to create g-VBC-x and g-VBC-x-co-Sty-z graft copolymers, respectively. The controlled nature of the polymerization as well as the use of a solvent allowed us to reduce the extent of the formation of the unwanted, non-grafted (co)polymer, thereby facilitating the graft copolymer's purification. The obtained graft copolymers were used to prepare films via solution casting using chloroform. The -CH₂Cl functional groups of the VBC grafts were then quantitatively converted to -CH₂(CH₃)₃N⁺ quaternary ammonium groups via reaction with trimethylamine directly on the films, and the films, therefore, were investigated as anion exchange membranes (AEMs) for potential application in a water electrolyzer (WE). The membranes were extensively characterized to assess their thermal, mechanical, and ex situ electrochemical properties. They generally presented ionic conductivity comparable to or higher than that of a commercial benchmark as well as higher water uptake and hydrogen permeability. Interestingly, the styrene/VBC-grafted copolymer was found to be more mechanically resistant than the corresponding graft copolymer not containing the styrene component. For this reason, the copolymer g-VBC-5-co-Sty-16-Q with the best balance of mechanical, water uptake, and electrochemical properties was selected for a single-cell test in an AEM-WE.

A Simple and Convenient Method for Preparing Fluorine-Free Durable Superhydrophobic Coatings Suitable for Multiple Substrates

Superhydrophobic coatings have attracted a lot of attention due to their excellent self-cleaning and anti-fouling capabilities. However, the preparation processes for several superhydrophobic coatings are intricate and expensive, which restricts their usefulness. In this work, we present a straightforward technique for creating durable superhydrophobic coatings that can be applied to a variety of substrates. The addition of C9 petroleum resin to a styrene-butadiene-styrene (SBS) solution lengthens the SBS backbone and undergoes a cross-linking reaction to form a dense spatial cross-linked structure, improving the storage stability, viscosity, and aging resistance of the SBS. The combined solution functions as a more stable and effective adhesive. Using a two-step spraying technique, the hydrophobic silica (SiO₂) nanoparticles solution was applied to the surface to create durable nano-superhydrophobic coatings. Additionally, the coatings have excellent mechanical, chemical, and self-cleaning stability. Furthermore, the coatings have wide application prospects in the fields of water-oil separation and corrosion prevention.

Laboratory Evaluation of Asphalt Binders Containing Styrene-Butadiene-Styrene (SBS) and Processed Oil

The study presents an experimental evaluation to improve the resistivity of binders with "Styrene-Butadiene-Styrene" (SBS) and "Processed oil" by studying the physical properties, rheology, and cracking. For this experiment, PG 64-22 was mixed with SBS at different percentages of 5%, 10%, and 15% by weight of the original binder with two processed oil contents of 6% and 12% by weight of the binder. Laboratory tests have been conducted at various high, medium, and low temperature ranges to evaluate their properties. The processed oil polymer modified asphalt (PMA) binder is artificially aged in both the short and long-term using a Rolling Thin Film Oven (RTFO) and a Pressure Aging Vessel (PAV). The Superpave testing method was performed on modified binders using a Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR). The results of this study illustrate (1) The addition of SBS leads to higher viscosity, but the co-modification of asphalt binder with the processed oil shows a significant modulation of the viscosity value. (2) In addition, processed oil reduced the resistance to rutting, but the addition of SBS significantly improved the rutting resistance of the asphalt binder. (3) The addition of SBS and processed oil improved the value of G sin δ, notably. (4) According to BBR, it has been shown that the addition of SBS in addition to the processed oil improves the stiffness values of modified asphalt binders.

Temperature and Aging Effects on the Rheological Properties and Performance of Geopolymer-Modified Asphalt Binder and Mixtures

Using geopolymer as a modifier for asphalt binders and mixtures gained momentum for investigation in recent decades. Limited research investigations attempted to link the effect of temperature and traffic loading on the rheological properties and performance of geopolymer-modified asphalt binders. The primary objective of this study is to evaluate the effect of fly ash-based geopolymer (GF), styrene-butadiene-styrene (SBS), and the combination of GF with SBS on the rheological properties and performance of asphalt binders at low and intermediate temperatures. The rheological properties and performance of neat and modified asphalt binders (4%GF, 8%GF,12%GF, 2%SBS, and hybrid (2%SBS+8%GF)) were evaluated utilizing dynamic shear rheometer (DSR) and bending beam rheometer (BBR) devices. To evaluate the fatigue resistance of asphalt binders, the linear amplitude sweep (LAS) and viscoelastic continuum damage (VECD) models were applied. The dynamic or complex modulus and moisture damage resistance were measured to investigate the influence of modifiers on the performance of asphalt mixtures. The findings demonstrated that for both unaged and RTFO-aged asphalt binders, additives reduced the temperature sensitivity of both G' and G″. When the binders were exposed to long-term aging using a pressure aging vessel (PAV), it was noticed that the 8%GF binder became more susceptible to temperature changes. The 2%SBS binder had the lowest creep stiffness compared with the neat and other modifiers, while the hybrid binder exhibited the highest resistance to fatigue distress at different temperatures compared with the other binders. The modified asphalt mixes (8%GF, 2%SBS, and hybrid) achieved the maximum tensile strength (St) compared with the neat asphalt binder, with an increase of more than 80%. The St increased from 580.4 kPa to 740.4 kPa, 884.8 kPa, and 917.4 kPa by utilising the 8%GF, 2%SBS, and hybrid binders, respectively. Furthermore, the modified asphalt mixture exhibited more ability to resist cracking, attaining the highest fracture energy in dry and freeze-thaw conditions.

Bond strength to different CAD/CAM lithium disilicate reinforced ceramics

OBJECTIVE

To evaluate the microstructure and the influence of applying universal adhesive only versus universal adhesive with additional silane application on shear bond strength (SBS) to four different lithium disilicate ceramic (LDC) materials.

MATERIAL AND METHODS

Specimens (n = 240, 1.5 mm thick) cut from four different CAD/CAM materials were polished and etched with 4.5% hydrofluoric (HF) acid according to manufacturers' instructions (20 s: IPS e.max CAD, n!ce; 30 s: Amber Mill, CEREC Tessera). For cementation, either universal adhesive only or silane + universal adhesive were applied before prefabricated composite cylinders were cemented using a dual-cure resin cement. SBS testing was performed either after 24 h or after 20,000 cycles thermocycling +2 months water storage. Surfaces were analyzed with stereomicroscope for failure mode and with scanning-electron microscopy for microstructure of the LDC. Statistical analysis of the data was performed with non-parametric tests at α = 0.001.

RESULT

SBS values for non-aged specimens ranged from 29.08 to 17.87 MPa and for aged specimens from 22.24 to 3.01 MPa. SBS was significantly reduced when silane was omitted after aging, (p < 0.001). Failure mode was mostly mixed with some cohesive failures in the LDC.

CONCLUSION

Bond strengths are highly affected by the CAD/CAM LDC and their microstructures. The application of silane after hydrofluoric etching is still essential to obtain long-term bonding, irrespective of the presence of silane in the universal adhesive. Water degradation can significantly affect long-term bonding to novel LDC.

CLINICAL SIGNIFICANCE

When using a universal adhesive for bonding to LDC restorations, the best long-term bond is achieved if an additional application of silane precedes the universal adhesive.

Aging Characterizations of Modified Asphalt Binders Based on Low Field Nuclear Magnetic Resonance (LF-NMR)

Styrene-butadiene-styrene block copolymer (SBS) and crumb rubber modifier (CRM) are commonly used modifiers to modify asphalt binders. The aging of modified asphalt binders is an important factor affecting their performance. In this paper, the effects of the two modifiers (i.e., SBS, CRM) on the aging of modified asphalt binders were studied by using low field nuclear magnetic resonance (LF-NMR) technology and dynamic shear rheological (DSR) tests. Test results showed that when T2, a parameter of relaxation time from NMR test, was within 2.2 milliseconds, the relaxation peak of both modified and unmodified asphalt binders tested showed two peaks (i.e., "M" shape), and when it was greater than 2 milliseconds, extra peaks appeared only in the modified asphalts. These extra peaks gradually disappeared with increased aging; the modifiers carried signal intensities of their own. The addition of a modifier changes the law of "the greater the viscosity of asphalt, the shorter the T2 relaxation time". With the aging process, the normalized peak area (NPA) from NMR decreased, and rutting resistance factor from DSR increased. However, the NPA of modified asphalt increased after the PAV test, which may be related to the change of H semaphore. The rheological properties of the asphalt binders before and after aging were well-correlated with the NPA of T2.

Study on SBS Optimal Block Ratio Based on Molecular Simulation

The block ratio of SBS is an important factor influencing the swelling effect of modified asphalt, but the effect of the block ratio in the swelling process cannot be accurately studied by macro testing. In order to solve this problem and screen out the optimal SBS block ratio, molecular models of asphalt and SBS with different block ratios were established by molecular simulation technology at the microscopic level, and an asphalt-SBS interaction layer system was established on this basis. The diffusion and adhesion effects of SBS with different block ratios were evaluated by calculating the immersion depth, diffusion coefficient, and adhesion work of SBS in asphalt. The results show that SBS has a physical cross-linking reaction with asphalt during swelling, and SBS with a higher butadiene block ratio exhibits a deeper immersion depth; thus, SBS with a 3/7 block ratio has the best performance in the modification process, which is superior to SBS with other block ratios, in terms of both the diffusion and adhesion effect. The performance of asphalt modified by SBS with different block ratios was tested using penetration, softening point, and ductility, and the results were consistent with the simulation results, which proved the reliability of the microscopic conclusions from a macro perspective.

Safety and feasibility of indocyanine green fluorescence angiography in pediatric gastrointestinal surgery: A systematic review

BACKGROUND

Although ICG-FA may be valuable in assessing anastomotic perfusion, reliable data on its use in pediatric gastrointestinal surgery is lacking. This systematic review analyzes whether ICG is useful for intestinal perfusion assessment in pediatric gastrointestinal surgery and safe to use in neonates.

METHODS

Systematic searches of PubMed, EMBASE & MEDLINE and CENTRAL were performed (last conducted December 6, 2021). The main inclusion criteria were (1) use of ICG for intestinal perfusion assessment and (2) use of ICG in young infants. Exclusion criteria were lack of an English or Dutch full-text and MINORS quality score <60%. Data was presented in overview tables. The usefulness in pediatric gastrointestinal surgery was assessed by surgical outcome. Safety of ICG in neonates was assessed by complication or adverse event occurrence.

RESULTS

Regarding intestinal perfusion assessment, four studies were included, reporting 45 patients (median age 1.5 years). ICG was considered useful for anastomotic blood flow evaluation and intraoperative determination of resection length. Regarding ICG safety in neonates, eight studies were included, reporting 46 infants (median age 24.9 days), of which 18 neonates. All but one studies reported the absence of complications or adverse events. Two studies reported subcutaneous dye retention, which fully disappeared within two weeks.

CONCLUSION

Although the number of available studies is small, ICG might be useful for intraoperative intestinal perfusion assessment, perhaps even more than conventional clinical assessment. Furthermore, its safety profile looks promising in neonates. Larger prospective studies are necessary to confirm these assumptions and seem warranted given the safety profile.

LEVELS OF EVIDENCE

Since this is a systematic review, a Level of Evidence for clinical studies cannot be determined for this manuscript.

Zero Shear Viscosity of Hybrid Modified Asphalts and Its Gray Correlation with Other Properties

The viscosity of modified asphalt binders is the most important property to ensure the durability of open-graded friction course (OGFC). Zero shear viscosity (ZSV) is considered to be the optimum result to reflect the rutting characterization of high viscosity modified asphalt binders, compared with conventional vacuum capillary viscosity. However, there are few reports on using ZSV to evaluate the material characteristics of hybrid modified asphalt binders and to establish the relationship between ZSV and other properties. In this paper, a high viscosity hybrid modified asphalt binder was prepared with Sty-rene-butadiene-styrene (SBS) and Crumb rubber modifier (CRM). ZSV, three major indicators, 60 °C dynamic viscosity, 135 °C Brookfield viscosity, and a dynamic rheological test were used to determine the properties of the hybrid modified asphalt binders. The relationship between ZSV and other properties was studied by the gray correlation analysis method. Results indicated that: (1) The viscosity of hybrid modified asphalt binders increases with the decreasing frequency. When the frequency tends to 0, the viscosity of asphalt at this time is zero shear viscosity; (2) The values of the ZSV of hybrid modified asphalt binders have a large increase as the dose of both CRM and SBS modifiers were increased; and (3) The ZSV at 60 °C correlated well with the performance properties of rutting factor (G*/sin(θ)), indicating that the ZSV of hybrid modified asphalt binders could be a good indicator of performance.

Study on the Influence of Nano-OvPOSS on the Compatibility, Molecular Structure, and Properties of SBS Modified Asphalt by Molecular Dynamics Simulation

The present research is carried out to inspect the influence of nano-OvPOSS (octavinyl oligomeric silsesquioxane) with different particle sizes on styrene-butadiene-styrene (SBS) modified asphalt through the method of molecular dynamics simulation. This nanomaterial is investigated for the first time to be used in asphalt modification. With the construction of modified asphalt simulation models and the analysis of their mixing energy, radius of gyration (R_g), radial distribution function (RDF), ratio of free volume (RFV), heat capacity, bulk modulus, and shear modulus, this study elucidates the influence of nano-OvPOSS on the compatibility between SBS and asphalt, on the structure of SBS as well as that of asphalt molecules and on the temperature stability and mechanical properties of SBS modified asphalt. The results show that nano-OvPOSS not only is compatible with SBS as well as with asphalt, but also is able to improve the compatibility between SBS and asphalt. Nano-OvPOSS is able to reinforce the tractility of branched chains of SBS and make SBS easier to wrap the surrounding asphalt molecules. The free movement space of molecules in the SBS modified asphalt system also shrinks. Moreover, the addition of nano-OvPOSS into SBS modified asphalt results in higher heat capacity, bulk modulus, and shear modulus of modified asphalt. All of these effects contribute to a more stable colloidal structure as well as more desirable temperature stability and deformation resistance of the modified asphalt system. The overall results of the study show that nano-OvPOSS can be used as a viable modifier to better the performance of conventional SBS modified asphalt.

IoT Sensor Network Using ESPAR Antenna Based on Beam Scanning Method for Direction Finding

Wireless sensor networks (WSNs) systems based on Internet of Things (IoT) have developed rapidly in recent years. However, interference is a major obstacle to relatively long-distance communications in such networks. It is also very complicated and challenging to fix the exact location of tags in the IoT sensor networks. To overcome these problems, in this paper, an electronic steering parasitic array radiator (ESPAR) antenna used as a beamformer to handle the interference and extend the communication range from the sensors or tags is suggested. In addition, an efficient method, namely beam scanning (BS), is proposed to find the directions of tags. The beam scanning method (BSM) can be used for the selective beam switching (SBS) system by designing an ESPAR or array of ESPAR antennas with the help of CST studio. The antennas exhibit higher gain (8.17 dBi, 11.40 dBi) and proper radiation pattern at a particular direction. In addition, the MATLAB simulation findings indicate that the proposed BSM algorithm provides longer communication range, i.e., 25 m. In order to maximize range while avoiding interference, it is necessary to determine the direction and precise orientation of the tag in the WSN communication systems. Consequently, this work could be applied to an IoT sensor network such as an electrocardiogram system by providing better advantages such as higher localization accuracy and longer operating range.

Preparation of mango peel-waste pectin-based nanofibers by solution blow spinning (SBS)

An essential prerequisite for successful solution blow spinning (SBS) is the presence of effective molecular entanglements of polymers in the solution. However, the fabrication of biopolymer fibers is not as straightforward as synthetic polymers. Particularly for biopolymers such as pectin, molecular entanglements are essential but insufficient for successful spinning through the SBS production method. Such a challenge is due to the biopolymer's complex nature. However, incorporating an easily spinnable polymer precursor, such as polyacrylonitrile (PAN), to pectin effectively enabled the production of fibers from the SBS process. In this process, PAN-assisted pectin nanofibers are produced with average diameters ranging from 410.75 ± 3.73 to 477.09 ± 6.60 nm using a feed flow rate of 5 ml h^-1, air pressure of 3 bars, syringe tip to collector distance at 30 cm, and spinning time of 10 min. PAN in DMSO solvent at different volume ratios (i.e. 35%-55% v/v) was critical in assisting pectin to produce nanofibers. The addition of a high molecular weight polymer, PAN, to pectin also improved the viscoelasticity of the solution, eventually contributing to its successful SBS process. Furthermore, the composite SBS-spun fibers obtained suggest that its formation is concentration-dependent.

Deep learning based topic and sentiment analysis: COVID19 information seeking on social media

Social media platforms have become a common place for information exchange among their users. People leave traces of their emotions via text expressions. A systematic collection, analysis, and interpretation of social media data across time and space can give insights into local outbreaks, mental health, and social issues. Such timely insights can help in developing strategies and resources with an appropriate and efficient response. This study analysed a large Spatio-temporal tweet dataset of the Australian sphere related to COVID19. The methodology included a volume analysis, topic modelling, sentiment detection, and semantic brand score to obtain an insight into the COVID19 pandemic outbreak and public discussion in different states and cities of Australia over time. The obtained insights are compared with independently observed phenomena such as government-reported instances.

Viscoelastic Behavior and Phase Structure of High-Content SBS-Modified Asphalt

To investigate the effect of styrene-butadiene-styrene (SBS) modifier content on the viscoelastic behavior of SBS-modified asphalt (SBSMA) at different temperatures and phase structures, the star SBS modifier was chosen to fabricate seven types of SBSMA with different contents. Multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), and low-temperature frequency sweep tests were adopted to study the influence of SBS modifier content on the viscoelastic performance of SBSMA at high to low temperatures. The SBSMA’s microstructure with different contents was investigated using a fluorescence microscope. The results indicated that the change in non-recoverable creep compliance and creep recovery rate was bounded by 4.5% content at high temperatures, with an apparent turning point. The changing slope of content at less than 4.5% was much higher than that of the content greater than 4.5%. At medium temperatures, the fatigue life of SBSMA increased exponentially with the rising modifier content. The rate of increase in fatigue life was the largest as the content increased from 4.5% to 6.0%. At low temperatures, the low-temperature viscoelastic property index G (60 s) of SBSMA decreased logarithmically as the modifier content increased. In terms of the microscopic phase structure, the SBS modifier gradually changed from the dispersed to the continuous phase state with the increasing SBS modifier content.

Study on the Conventional Performance and Microscopic Properties of PPA/SBS-Modified Bio-Mixed Asphalt

To promote the construction of environmentally friendly, sustainable pavements and solve the impact of the scarcity of asphalt resources on highway development, bio-mixed asphalt (BMA) modified by SBS and polyphosphoric acid (PPA) was prepared, and the influence of the ratio of bio-asphalt (BA) replacing petroleum asphalt on different PPA/SBS blending schemes was explored through conventional property tests. According to each PPA/SBS blending scheme, the optimal replacement ratio of bio-asphalt was optimized, and the microstructure and distribution morphology of different PPA/SBS-modified BMA were evaluated. Conventional property test results show that with the same PPA/SBS content, the replacement ratio of bio-asphalt has a significant impact on the conventional performance of composite-modified asphalt, but the appropriate replacement ratio of bio-asphalt can improve the storage stability and conventional performance of composite-modified asphalt; in micromorphological analysis, it was found that the number of bee-like structures on the surface of the modified BMA decreased significantly, which indicated that the molecular heterogeneity of various components in the asphalt was reduced. In addition, bio-asphalt changed the particle morphology and improved the dispersity of SBS in asphalt. The composite-modified BMA had a lower SBS content, but its conventional performance was still excellent—so it has significant application prospects in road engineering.

Short Bowel Syndrome and Dysmotility

Due to recent advances, the mortality due to short bowel syndrome (SBS) has significantly decreased, but the morbidities are still high. Morbidities arising specifically due to dysmotility in SBS include feeding intolerance, prolonged dependence on parenteral nutrition, and associated complications such as intestinal failure associated liver disease, and bloodstream infections. The understanding of the pathogenesis of dysmotility in SBS has improved vastly. However, the tools to diagnose dysmotility in SBS in infants are restrictive, and the medical therapies to treat dysmotility are limited. Surgical techniques available for the treatment after failure of conservative management of dysmotility offer hope but carry their associated risks. The evidence to support either the medical therapies or the surgical techniques to treat dysmotility in SBS in children is scarce and weak. Development of newer therapies and efforts to build evidence to support currently available treatments in treating dysmotility in SBS is needed.

Exposures, Symptoms and Risk Perception among Office Workers in Relation to Nanoparticles in the Work Environment

Submicroscopic nanoparticles (NPs) in air have received much attention due to their possible effects on health and wellbeing. Adverse health impacts of air pollution may not only be associated with level of exposure, but also mediated by the perception of the pollution and by beliefs of the exposure being hazardous. The aim of this study was to test a model that describes interrelations between NP pollution, perceived air quality, health risk perception, stress, and sick building syndrome. In the NanoOffice study, the level of NPs was measured and a survey on health risk perception was conducted among 260 employees in twelve office buildings in northern Sweden. Path analyses were performed to test the validity of the model. The data refute the model proposing that the NP exposure level significantly influences stress, chronic diseases, or SBS symptoms. Instead, the perceived exposure influences the perceived risk of NP, and the effect of perceived exposure on SBS and chronic disease is mediated by stress. There was little concern about nanoparticles, despite relatively high levels in some facilities. Perceived pollution and health risk perception may explain a large part of the environmentally induced symptoms and diseases, particularly in relatively low levels of pollution. The research results raise important questions on the physiologically or psychologically mediated health effects of air pollution.

Application of Hyperspectral Imaging for identification of aging state of Styrene-Butadiene-Styrene

In the context of the circular economy, the sorting process during recycling of polymers is essential as regards the efficiency of the process itself and the quality of the so-obtained recycled materials. In this paper, the application of Hyperspectral Imaging (HSI) is proposed for this purpose, providing additional insight into the state of aging and the polymer quality. The underlying study comprises HSI in the wavelength range of 1115-1678 nm considering artificially aged Styrene-Butadiene-Styrene (SBS), where aging is performed for 2, 5, 10, 15 and 20 days in a forced-draft oven at a temperature of 105 °C. The obtained HSI spectra are normalized using the Standard Normal Variate (SNV) method, with the normalized spectra as well as their first and second derivative entering the modeling attempt for SBS aging. For the latter, different partial least squares regression (PLSR) models are evaluated, where the original spectra achieved a correlation of R²=0.94 and a root mean squared error of prediction (RMSEP) of 1.83 days, showing the suitability of HSI for the proper identification of the state of aging of SBS and its potential use for other polymers.

Is external hydrocephalus a possible differential diagnosis when child abuse is suspected?

Background

Criteria for diagnosing abusive head trauma (AHT) or “shaken baby syndrome” are not well defined; consequently, these conditions might be diagnosed on failing premises.

Methods

The authors have collected a total of 28 infants, from the US (20) and Norway (8), suspected of having been violently shaken, and their caregivers had been suspected, investigated, prosecuted or convicted of having performed this action. Among 26 symptomatic infants, there were 18 boys (69%) and 8 girls (31%)—mean age 5.1 month, without age difference between genders.

Results

Twenty-one of 26 symptomatic children (81%) had a head circumference at or above the 90 percentile, and 18 had a head circumference at or above the 97 percentile. After macrocephaly, seizure was the most frequent initial symptom in 13 (50%) of the symptomatic infants. Seventeen (65%) of the symptomatic infants had bilateral retinal haemorrhages, and two had unilateral retinal haemorrhages. All infants had neuroimaging compatible with chronic subdural haematomas/hygromas as well as radiological characteristics compatible with benign external hydrocephalus (BEH).

Conclusions

BEH with subdural haematomas/hygromas in infants may sometimes be misdiagnosed as abusive head trauma. Based on the authors’ experience and findings of the study, the following measures are suggested to avoid this diagnostic pitfall: medical experts in infant abuse cases should be trained in recognising clinical and radiological BEH features, clinicians with neuro-paediatric experience should always be included in the expert teams and reliable information about the head circumference development from birth should always be available.

The effect of fecal microbial transplant on intestinal microbial composition in short bowel neonatal piglets

BACKGROUND

Short bowel syndrome (SBS) in neonates is associated with microbial dysbiosis due to intestinal surgery, prolonged hospitalization, enteral nutrition, and repeated antibiotic exposure. Sepsis and liver disease, leading causes of morbidity and mortality in SBS, may relate to such intestinal dysbiosis. We investigated the safety and feasibility of fecal microbial transplant (FMT) to alter intestinal microbial composition in SBS piglets.

METHODS

Following a 75% distal small intestinal resection, piglets were fed parenteral nutrition (PN) and elemental diet (ED), and randomized to saline (SAL, n=12) or FMT (n=12) treatments delivered by gastric tube on day 2 (d2). FMT donor was a healthy adult pig. Comparisons were also made to healthy sow-fed littermate controls (SOW, n=6). Stool samples were collected daily, and tissue samples were collected at baseline and termination. Microbial DNA was extracted from stool and analyzed using 16S rRNA sequencing.

RESULTS

All piglets survived to the endpoint. On d2-4, FMT piglets had some differences in microbiota composition, compared to SAL, SOW, and donor. Between base and term, there were transitory changes to alpha and beta diversity in FMT and SAL.

CONCLUSION

FMT treatment in post-surgical neonatal piglets with SBS appears safe, with no increase in sepsis and no mortality. In SBS piglets, FMT induced transient changes to the intestinal microbiota. However, these changes did not persist long-term. This article is protected by copyright. All rights reserved.

Evaluation of the Aging of Styrene-Butadiene-Styrene Modified Asphalt Binder with Different Polymer Additives

A wide variety of polymer additives have been widely used in recent years. However, the effect of different polymer additives on the durability of asphalt binders has not been investigated thoroughly. To evaluate the aging property of styrene-butadiene-styrene (SBS) asphalt binder with different polymer additives, three polymer modifiers, namely high modulus modifier (HMM), anti-rutting agent (ARA), and high viscosity modifier (HVM), were added to it. First, the Thin Film Over Test (TFOT) and Pressure Aging Vessel (PAV) was performed on the asphalt binders. The rheological properties of the four asphalt binders before and after aging were then checked by the Dynamic Shear Rheometer Test (DSR). The chemical compositions of the asphalt binders were determined by the Fourier Transform Infrared Spectrometer (FTIR) test. Several aging indicators were adopted to reflect the aging degree of the asphalt binders. The results show that when polymer additives are added to the SBS asphalt binder, the complex modulus, storage modulus, loss modulus, and rutting factor substantially increase and the phase angle decreases. All the test parameters become higher after aging. The phase angle of the SBS asphalt binder is the highest at both unaged and aged states, while its other parameters values are the smallest. Moreover, the Carbonyl Aging Indicator (CAI) of SBS with polymer additives becomes lower under both TFOT and PAV conditions, indicating that polymer additives can improve the aging resistance of SBS asphalt, of which HVM modifies the aging resistance best. Complex Modulus Aging Indicator (CMAI) and Storage Modulus Aging Indicator (SMAI) have the best correlation coefficients with CAI, and the two aging indicators can be used to predict the aging degree of polymer modified asphalt binders.

Study on Ultraviolet Aging Mechanism of Carbon Nanotubes/SBS Composite-Modified Asphalt in Two-Dimensional Infrared Correlation Spectroscopy

In order to explore the influence mechanism of carbon nanotubes on the ultraviolet (UV) aging properties of the SBS-modified asphalt binder, the changes of functional groups in the one-dimensional infrared spectrum and two-dimensional infrared correlation spectrum are studied in this paper. The results show that the UV aging process of the SBS-modified asphalt binder is the process of alkane chain cleavage and reorganization, the formation of oxygen-containing functional groups and decomposition of SBS. The incorporation of carbon nanotubes can reduce the mutual conversion of methyl and methylene functional groups, inhibit the decomposition of butadiene and the destruction of C = C double bonds in SBS. The degradation of SBS during the process of UV aging leads to the change of many functional groups and acceleration of the aging of the SBS-modified asphalt binder. The addition of carbon nanotubes can effectively alleviate the degradation of SBS and the formation of oxygen-containing functional groups at the early stage of UV aging, and reduce the influence of these two changes on other functional groups; thus, improving the anti-aging performance of the SBS-modified asphalt binder.

CD40 Agonist Monoclonal Antibody-Mediated Hepatitis in TNF-Receptor 1 Gene Knockout Mice

Tumor necrosis factor-alpha (TNF-α) plays an important role in liver inflammation. CD40-CD40 ligand (CD40-CD40L) is a key receptor–ligand signaling pair involved in the adaptive immune response and pathogenesis of autoimmune diseases. In mice, CD40 activation leads to sickness behavior syndrome (SBS) comprising weight loss, sleep disruption and depression, which can be blocked by administration of the TNF-inhibitor etanercept. In the present study, we assessed the extent of hepatic inflammation in mice devoid of the TNF-receptor 1 (TNFR1)-mediated signaling pathway. The TNFR1-depleted (TNFR1−/−) adult mice and their wild type littermates were given a single intra-peritoneal injection of CD40 agonist monoclonal antibody (mAb) or rat IgG2a isotope control. As described previously, TNFR1−/− mice were protected from SBS upon CD40 mAb treatment. Cd40, tnf and tnfr1 mRNA and Tnf-α peptide were increased in the liver of CD40 mAb-stimulated wild type mice. Serum alanine aminotransferase was elevated in both CD40-activated wild type and TNFR1−/− mice. TNFR1−/− mice showed much less intra-parenchymal infiltrates, hepatocellular necrosis, and perivascular clusters upon CD40 mAb activation than their wild type littermates. A gene expression microarray detected increased activity of metabolic and detoxification pathways and decreased activity of inflammatory pathways. We conclude that immune activation and development of liver inflammation in CD40L interactions depend on TNFR1-mediated signaling pathways and are counteracted by alterations in metabolic pathways.

Shear bond strength of metallic brackets bonded to enamel pretreated with Er,Cr:YSGG LASER and CPP-ACP

Background

Increased risk of enamel demineralization during and after orthodontic treatment raises the demand for better preventive measures including combinations of laser, CPP-ACP, and fluoride. The combination of Er,Cr:YSGG laser with CPP-ACP was proved to have a synergetic effect compared to each of them alone. Shear bond strength (SBS) of orthodontic brackets bonded to the enamel surface after being treated with preventive measures is critical. The aim of this study was to compare the SBS and failure mode of metallic brackets bonded to teeth with no pretreatment and pretreated enamel surface, either with Er,Cr:YSGG laser alone or combined with CPP-ACP.

Methods

Sixty sound extracted human premolar teeth were allocated randomly to 3 groups: In Group 1 (control), teeth were etched and bonded directly; in Group 2, laser pretreatment of the enamel surface was done followed by etching and bonding as in the control group; in Group 3, the enamel surface was lased then CPP-ACP was applied according to the manufacturer instructions, etched and bonded. SBS and Adhesive remnant index (ARI) were evaluated.

Results

No significant differences were found between the 3 groups neither in the SBS nor in the ARI scores.

Conclusions

The use of combined Er,Cr:YSGG laser with CPP-ACP as a preventive measure before bonding orthodontic brackets does not endanger the bracket’s bonding strength.

Synergy Effect of Nano-Organic Palygorskite on the Properties of Star-Shaped SBS-Modified Asphalt

With the rapid development of economic construction, styrene-butadiene-styrene (SBS)-modified asphalt is being more and more widely used in highway engineering, but there are still many deficiencies in the process of its use. In order to further improve its performance for use, nano-organic palygorskite (A-Pal) and star-shaped SBS were compounded to obtain modified asphalt in this study. The high-temperature stability of SBS-modified asphalt was enhanced after incorporation with A-Pal for the high-temperature stability test by a dynamic shear rheometer. The A-Pal should improve the surface free energy and adhesion of SBS-modified asphalt by the water stability test analysis. The aging test shows that A-Pal can reduce the thermal oxygen decomposition of SBS and improve the anti-aging performance and the fatigue resistance of SBS-modified asphalt. A-Pal has a certain improvement effect on the low temperature performance of SBS-modified asphalt as shown by a low temperature crack resistance test. A-Pal-compounded SBS-modified asphalt features good storage stability in normal temperatures with the lowest critical compatibility temperature.

Polymer-Bitumen Interaction: A Correlation Study with Six Different Bitumens to Investigate the Influence of SARA Fractions on the Phase Stability, Swelling, and Thermo-Rheological Properties of SBS-PmB

The aim of this work is to determine the influence of the bitumen chemistry on the rheological performance of bitumen and polymer modified bitumen (PmB), as well as the polymer distribution and storage stability. Six different bitumens and their 5 wt.% SBS mixtures are considered in this work. The bitumen composition was determined by SARA fractioning, which was then correlated with the glass transition temperature, complex modulus |G*|, and phase angle, which were obtained by parallel-plate dynamic shear rheology in the temperature range of -25 to 65 °C. The polymer distribution, which was derived from fluorescence microscopy images and the storage stability (determined by tube test) also correlated with the SARA fractions. It was found that the saturates decrease |G*| and Tg and increase the phase angle in crude bitumen, while the asphaltenes increase |G*| and the phase angle. For PmB, the amount of swelling was determined by the saturate content of bitumen. The glass transition temperature of PmBs increases for low saturate and decreases for high saturate contents. |G*| and the phase angle of PmBs correlates with the saturate content, with a varying influence depending on a high or low saturate content and the temperature range due to saturate depletion in the bitumen-rich phase and the varying vol% polymer-rich phase. The aromatic and resin fractions show no correlation in the considered bitumens and PmBs.

Research on the Mechanism of Interaction between Styrene-Butadiene-Styrene (SBS) and Asphalt Based on Molecular Vibration Frequency

Based on the four-component theory of asphalt, molecular models of the saturate, aromatic, resin, and asphaltene were constructed, respectively. The styrene–butadiene–styrene (SBS) polymer was used as the modifier. Using density functional theory (DFT) to study the effect of SBS on the molecular vibration of each component of asphalt, the vibration spectrums and binding energy of the systems composed of SBS and each component molecule of asphalt were calculated. Prepared SBS modified asphalt and measured Fourier transform infrared spectroscopy (FTIR) before and after the experiment. The results show that after SBS was added to asphalt, no chemical reaction occurred, and the system was mainly physical blending. The vibrational peak intensity of SBS and the light components of asphalt (saturate and aromatic) is stronger than that of SBS and the heavy components of asphalt (resin and asphaltene). The interaction strengths of asphalt components and polybutadiene (PB) blocks, polystyrene (PS) blocks of SBS are different. The binding energy of SBS and the saturate is the lowest and the bonding of the system is weakest. The bonding of the systems of SBS and the aromatic, resin, asphaltene is stable, and the stability of these systems are all stronger than that of SBS and the saturate.

Comparison of shear bond strength and ARI of four different adhesive systems used to bond molar tubes: An in vitro study

OBJECTIVE

The purpose of this in vitro study was to determine and compare the shear bond strength and ARI score of one traditional etch-and-rinse adhesive system serving as control, with those of two other all-in-one adhesives but with enamel acid etching preceding their application, and of one new 8th generation all-in-one bonding agent combined with a traditional adhesive used to bond stainless steel buccal tubes to molar teeth.

MATERIAL AND METHODS

Four groups of teeth were formulated according to the adhesive system used to bond the tubes on the molars. Shear bond strength was measured using a universal testing machine (Hounsfield, UK). After debonding, each enamel surface was imaged using Inspex HD l080p Vesa camera (Ash Technologies Ltd., Ireland) to determine the ARI score.

RESULTS

The mean SBSs in MPa for the four groups were respectively: A: 9.640 (±3.69), B: 10.261 (±3.03), C: 9.689 (±2.48), D: 8.412 (±3.02). No statistically significant differences were neither found through one-way ANOVA to exist between the group means (P: 0.715), nor for the ARI score frequence through Chi² (P: 0.534). Maxcem Elite showed four and G-Premio Bond zero instances of enamel fracture.

CONCLUSIONS

1. SBSs of all adhesives and ARI score distributions did not present any significant differences when used to bond stainless steel molar tubes. 2. All adhesives presented with acceptable shear bond strengths for clinical use. 3. Maxcem Elite under the tested conditions presented the greatest and G-Premio the least number of enamel fractures.

vcfView: An Extensible Data Visualization and Quality Assurance Platform for Integrated Somatic Variant Analysis

Motivation:

Somatic mutations can have critical prognostic and therapeutic implications for cancer patients. Although targeted methods are often used to assay specific cancer driver mutations, high throughput sequencing is frequently applied to discover novel driver mutations and to determine the status of less-frequent driver mutations. The task of recovering somatic mutations from these data is nontrivial as somatic mutations must be distinguished from germline variants, sequencing errors, and other artefacts. Consequently, bioinformatics pipelines for recovery of somatic mutations from high throughput sequencing typically involve a large number of analytical choices in the form of quality filters.

Results:

We present vcfView, an interactive tool designed to support the evaluation of somatic mutation calls from cancer sequencing data. The tool takes as input a single variant call format (VCF) file and enables researchers to explore the impacts of analytical choices on the mutant allele frequency spectrum, on mutational signatures and on annotated somatic variants in genes of interest. It allows variants that have failed variant caller filters to be re-examined to improve sensitivity or guide the design of future experiments. It is extensible, allowing other algorithms to be incorporated easily.

Availability:

The shiny application can be downloaded from GitHub (https://github.com/BrianOSullivanGit/vcfView). All data processing is performed within R to ensure platform independence. The app has been tested on RStudio, version 1.1.456, with base R 3.6.2 and Shiny 1.4.0. A vignette based on a publicly available data set is also available on GitHub.

The Use of De-Vulcanized Recycled Rubber in the Modification of Road Bitumen

Rubber from recycled car tires and styrene-butadiene-styrene (SBS) were used for the chemical modification of commercially available road bitumen 50/70 (EN 12591). The modification process began with the addition of rubber into asphalt and heating the whole amount at the temperature of 190 °C or 220 °C. Under such conditions, de-vulcanization of rubber took place. Next, SBS and sulfur as a cross-linker were added and the heating was continued so that cross-linking of SBS and the de-vulcanized rubber proceeded. In the studies on the influence of rubber concentration on the final properties of asphalt 10% or 15% of rubber was considered. Chemical modification reactions were performed within 2, 4, and 8 h. The results showed that both the modification at 190 °C and 220 °C affected the properties of the base asphalt efficiently, although the asphalt modified at 190 °C contained more non-degraded rubber. Increasing the modification time led to dissolution of the rubber crumbs and its de-vulcanization. Bitumens modified in this way are characterized by high storage stabilities. Their behavior at low temperatures also deserves attention.

Mechanistic-empirical evaluation of specific polymer-modified asphalt binders effect on the rheological performance

Major distresses such as rutting, fatigue, and thermal cracking are facing asphalt pavement structures due to continuous heavy traffic loading and climate change. The modification of asphalt binders (one of the main components of the asphalt paving mix) has the potential to mitigate distresses through using different additives. Polymer modified asphalt (PMA) binders showed a noticeable resistance to pavement distresses as reported in previous studies. The present study aims to evaluate the effect of polymer modification on the rheological properties of asphalt binders through laboratory tests. The polymers included styrene-butadiene-styrene (SBS) and epolene emulsifiable (EE2) types. The 60/70 binder was used as a control for comparison. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was also utilized to simulate the effect of PMA binders on the rheological properties under different climatic conditions and structural capacities. Additionally, the MEPDG was further utilized to compare the effect of asphalt binders on rheological properties using four different binder input levels. Findings of the study showed that laboratory tests experienced varying outcomes regarding the most efficient asphalt binder by means of distresses resistance. However, the MEPDG evaluation showed that the overall ranking of asphalt binders positively impacting the rheological properties was as following: (1) 4.5% EE2 PMA, (2) 4% EE2 PMA, (3) 60/70 binder, (4) 5% SBS PMA, and (5) 4% SBS PMA binders. Furthermore, statistical analysis illustrated that the effect of using different binder input levels on the performance of pavement varied relatively to the evaluated distresses. The analysis showed that using different binder input levels would affect, to a certain extent, the asphalt binder influence on rheological properties only when evaluating rutting and fatigue distresses. Therefore, it is recommended that precise asphalt binder inputs, that is, shear complex modulus (G*) and phase angle (δ) are used when designing pavement structures in regions with hot and mild climate conditions.

Effect of elasticity on electrospun styrene-butadiene-styrene fibrous membrane cell culture behaviors

In this study, elastic styrene-butadiene-styrene (SBS), non-elastic SBS and their blends at different ratios were electrospun into fibrous membranes and their cell biocompatibility was evaluated. The as-spun fibers showed an average fiber diameter of 2 µm, and the fibrous membranes had pore size of 8 ± 0.01 µm. The blending ratios of the elastic with non-elastic SBSs showed little effect on fibrous structure, but affected the mechanical properties. All SBS membrane showed no cytotoxicity on endothelial cells (ECs). ECs attached and proliferated on all the SBS fibrous membrane scaffolds regardless of their elasticity. ECs maintained their polygonal shape on the scaffolds and they tended to orient along the fiber length. The SBS fibrous samples with elastic:non-elastic SBS weight ratios of 1:1 and 2:3 showed better cell viability than that of elastic and non-elastic SBS.

Solution Blow Spinning of Polyvinylidene Fluoride Based Fibers for Energy Harvesting Applications: A Review

Polyvinylidene fluoride (PVDF)-based piezoelectric materials (PEMs) have found extensive applications in energy harvesting which are being extended consistently to diverse fields requiring strenuous service conditions. Hence, there is a pressing need to mass produce PVDF-based PEMs with the highest possible energy harvesting ability under a given set of conditions. To achieve high yield and efficiency, solution blow spinning (SBS) technique is attracting a lot of interest due to its operational simplicity and high throughput. SBS is arguably still in its infancy when the objective is to mass produce high efficiency PVDF-based PEMs. Therefore, a deeper understanding of the critical parameters regarding design and processing of SBS is essential. The key objective of this review is to critically analyze the key aspects of SBS to produce high efficiency PVDF-based PEMs. As piezoelectric properties of neat PVDF are not intrinsically much significant, various additives are commonly incorporated to enhance its piezoelectricity. Therefore, PVDF-based copolymers and nanocomposites are also included in this review. We discuss both theoretical and experimental results regarding SBS process parameters such as solvents, dissolution methods, feed rate, viscosity, air pressure and velocity, and nozzle design. Morphological features and mechanical properties of PVDF-based nanofibers were also discussed and important applications have been presented. For completeness, key findings from electrospinning were also included. At the end, some insights are given to better direct the efforts in the field of PVDF-based PEMs using SBS technique.

Solution Blow Spinning of High-Performance Submicron Polyvinylidene Fluoride Fibres: Computational Fluid Mechanics Modelling and Experimental Results

Computational fluid dynamics (CFD) was used to investigate characteristics of high-speed air as it is expelled from a solution blow spinning (SBS) nozzle using a k-ε turbulence model. Air velocity, pressure, temperature, turbulent kinetic energy and density contours were generated and analysed in order to achieve an optimal attenuation force for fibre production. A bespoke convergent nozzle was used to produce polyvinylidene fluoride (PVDF) fibres at air pressures between 1 and 5 bar. The nozzle comprised of four parts: a polymer solution syringe holder, an air inlet, an air chamber, and a cap that covers the air chamber. A custom-built SBS setup was used to produce PVDF submicron fibres which were consequently analysed using scanning electron microscope (SEM) for their morphological features. Both theoretical and experimental observations showed that a higher air pressure (4 bar) is more suitable to achieve thin fibres of PVDF. However, fibre diameter increased at 5 bar and intertwined ropes of fibres were also observed.

Investigating the shear bond strength of five resin-based luting agents to zirconia ceramics

The present study investigated the bond strength and aging resistance performance of five resin-based luting agents to zirconia. A total of 100 large blocks (10.0 mm × 10.0 mm × 2.5 mm) and 100 small blocks (4.0 mm × 4.0 mm × 2.5 mm) of zirconia were airborne-particle abraded and randomly divided into five groups: (RelyX Ultimate [RUl]; Panavia F [PF]; Clearfil SA Luting [SAC]; Multilink Speed [MS]; and RelyX Unicem [RUn]). The small blocks were bonded to the large blocks using the resin-based luting agents. Shear bond strengths (SBS) and failure mode were determined before and after 5,000 thermocycles. After being stored in water for 24 h, the SBS were MS > PF > RUl > SAC > RUn (P < 0.05). After 5,000 thermocycles, the SBS were MS > SAC ≈ RUl > PF ≈ RUn (P < 0.05); the SBS of the PF, MS, and RUn groups were lower than that before 5,000 thermocycles (P < 0.01). Adhesive failure, cohesive failure, or mixed failure occurred in the specimens. In general, Clearfil SA Luting, a self-adhesive resin-based luting agent containing 10-methacryloxy decyl diphosphate, had good initial and durable SBS to zirconia and was a better adhesive.

Orthodontic Bracket Bonding Using Self-adhesive Cement to Facilitate Bracket Debonding

PURPOSE

To evaluate shear bond strength (SBS), adhesive remnant index (ARI), and orthodontic bracket base after debonding of orthodontic brackets bonded using two different adhesives.

MATERIALS AND METHODS

Ninety sound human premolars were divided into three groups of n = 30. 1. Transbond, where brackets were bonded with Transbond XT (3M Unitek); 2. Multilink, where brackets were bonded with Multilink Speed (Ivoclar Vivadent); 3. Multilink+etch, where brackets were bonded using Multilink Speed after etching enamel. ARI scores were obtained using a stereomicroscope. SEM was used to evaluate the treated enamel surfaces and the base of the brackets. One-way ANOVA was performed to statistically analyze SBS. The Kruskal-Wallis test was conducted to investigate ARI scores, followed by multiple comparison tests (p < 0.05).

RESULTS

SBS was significantly lower in the Multilink group compared to the other groups (p < 0.05). SEM evaluation revealed minimum penetration of resin tags within the enamel and that most of the resin was attached to the base of the brackets in the Multilink group compared to the other two groups (p < 0.05).

CONCLUSION

Application of Multilink Speed on nonetched enamel provides acceptable SBS of orthodontic brackets bonded to enamel with minimum penetration of resin tags into enamel and less residual resin on tooth surfaces.

Efficient Endocytosis of Inorganic Nanoparticles with Zwitterionic Surface Functionalization

PEGylation, which has traditionally been the method of choice to enhance the colloidal stability of nanostructures designed for biological applications and to prevent nonspecific protein adsorption, is now being challenged by short zwitterionic ligands. Inspired by the zwitterionic nature of cell membranes, these ligands have the potential to push forward the field of nanoparticles for nanomedicine. In this work, we report a thorough analysis of the surface chemistry of silica-coated luminescent CdSe/CdS quantum dots functionalized with either PEG-silane or zwitterionic sulfobetaine-silane by quantitative nuclear magnetic resonance spectroscopy. We demonstrate the differences in the cellular uptake propensity between particles with these two ligands. Although both ligands offer good colloidal stability in a crowded cell culture medium, the zwitterionic-functionalized nanoparticles with an optimized ligand density showed to be more easily endocytosed by HeLa cells. This approach can readily be transferred to other nanoparticle systems offering a wealth of unique properties, with great potential for intracellular bioapplications.

Environmental Impacts of Styrene-Butadiene-Styrene Toughened Wood Fiber/Polylactide Composites: A Cradle-to-Gate Life Cycle Assessment

In this study, a life cycle assessment (LCA) was used to investigate the environmental benefits of using styrene-butadiene-styrene (SBS) to modify polylactide (PLA)-based wood plastic composites (WPCs), with a process-based and input–output hybrid model. The results showed that one metric ton of the SBS-modified WPCs required 1.93 × 10⁸ kJ of energy (Sample 2) and 46 m³ of water (Sample 4), and that it could produce 42.3 kg of solid waste (Sample 2) during its cradle-to-gate life cycle phases. The environmental impact load (EIL) and photochemistry oxidation potential (PCOP) accounted for the largest share, while the eutrophication potential (EP) took the smallest one. The total EIL index of Samples 1, 2, 3, and 4 added up to 1.942, 1.960, 1.899, and 1.838, respectively. The SBS-modified WPCs were found to be more environmentally friendly than their unmodified counterparts when they had the same or higher wood fiber (WF) content. SBS was viable to toughen the PLA-based WPCs from an environmental perspective. This cradle-to-gate LCA is likely to help optimize the manufacturing process and mitigate environmental impacts for the natural fiber-reinforced polymer biocomposites.

Feasibility study of the calm baby gently program: An educational baby book intervention on safe practices related to infant crying

BACKGROUND

Abusive head trauma (AHT) is a preventable form of child abuse.

OBJECTIVE

This project used a mixed method design to assess the feasibility of the Calm Baby Gently educational baby book intervention for promoting safe practices related to infant crying in an effort to prevent AHT.

PARTICIPANTS AND SETTING

Three pediatric practices participated between June 2016 and January 2018, including 1045 caregivers who attended their infant's 2-month well-child visit.

METHODS

Pediatric providers gave the educational baby book to caregivers at the 1-month well-child visit. Caregivers completed a survey at the 2-month well-child visit on their use and satisfaction with the book and responses to infant crying. Thematic analysis of qualitative feedback was performed. Responses to infant crying were compared quantitatively between caregivers who had and had not read the book.

RESULTS

Of the 819 caregivers (78%) who received the book, 92% (754) read it, and 51% (421) had another caregiver read it. Caregivers considered the book approachable, understandable, validating, and helpful for improving knowledge and skills related to infant crying. The book was rated more helpful by caregivers of younger age, male gender, and non-white race. Controlling for age, gender, and race, caregivers who read the book were more confident (p = 0.033) and had more knowledge on how to respond appropriately to infant crying (p = 0.019) than caregivers who had not read it.

CONCLUSIONS

Calm Baby Gently is a feasible and well-received AHT prevention program. Randomized controlled trials are needed to better understand its impact on knowledge, behavior, and AHT rates.

Influence of Overheating Phenomenon on Bitumen and Asphalt Mixture Properties

In the course of manufacturing, transport and installation, road bitumens and asphalt mixtures can be exposed to the impact of elevated process temperatures exceeding 240 °C. This mainly applies to the mixtures used for road pavements and bridge deck insulation during adverse weather conditions. The heating process should not change the basic and rheological properties of binders and the asphalt mixtures that to a degree cause the degradation of asphalt pavement durability. The work involved analyzing the properties of non-modified bitumens and SBS polymer modified bitumens, heated at temperatures of 200 °C, 250 °C and 300 °C for 1 h. Next, the asphalt mixtures were heated in the same temperatures. Based on the developed Overheating Degradation Index (ODI) it was demonstrated that polymer-modified bitumens were characterized by higher overheating sensitivity A_(ODI) than non-modified bitumens, which was confirmed by mixture test results. Overheating limit temperatures T_(ODI) were determined, which in the case of polymer-modified bitumens are up to 20 °C lower than for non-modified bitumens. When the temperature increases above T_(ODI), loss of viscoelastic properties occurs in the material which causes, among other effects, a loss of resistance to fatigue cracking.

The influence of enamel sandblasting on the shear bond strength and fractography of the bracket-adhesive-enamel complex tested in vitro by the DIN 13990:2017-04 standard

OBJECTIVES

This study was conducted in order to investigate whether enamel sandblasting as an adjunct or substitute to the acid-etch technique has an effect on the shear bond strength (SBS) and fractography of the bracket-adhesive-enamel complex using the DIN 13990:2017-04 standard.

MATERIALS AND METHODS

Upper central incisor brackets (discovery®, Dentaurum, Germany) were bonded using Transbond XT™ (3M Unitek, Germany) on bovine incisors prepared by four different methods (15 samples each): sandblasting with 27 μm Al₂O₃ at 1.2 bar (s), acid etching with 37.4% phosphoric acid (a), sandblasting with 27 μm Al₂O₃ at 1.2 bar followed by acid etching (s1a), and sandblasting with 50 μm Al₂O₃ at 5.7 bar followed by acid etching (s2a). The SBS and adhesive remnant index (ARI) were measured, followed by one-way analysis of variance and Fisher's exact tests at 5%.

RESULTS

The SBS in groups s (5.6 ± 2.2 MPa), a (17.1 ± 4.3 MPa), s1a (18.3 ± 4.3 MPa), and s2a (18.5 ± 4.6 MPa) indicated that the s group was significantly inferior to all the other groups (p < 0.001). Likewise, the ARI analysis indicated a different performance of the s group (mostly ARI of 0) compared to the other groups (p < 0.001) and a tendency for different ARI between the a and s1a/s2a groups.

CONCLUSIONS

In vitro enamel sandblasting could not substitute acid etching and did not offer improved SBS when used before acid etching, regardless of air pressure and powder granulation. Sandblasting without acid etching produced less residual resin on the tooth after debonding.

CLINICAL RELEVANCE

The clinical use of adjunct enamel sandblasting prior to etching to enhance SBS has to be questioned.