Temperature/pH/magnetic triple‐sensitive nanogel–hydrogel nanocomposite for release of anticancer drug

Hydrogels, nanogels and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for a long‐term drug release system. In this regard, the design and application of a nanocomposite hydrogel containing entrapped nanogel for drug delivery are demonstrated. To this aim, we first prepared an iron oxide nanocomposite nanogel based on poly(N‐isopropylacrylamide)‐co‐((2‐dimethylaminoethyl) methacrylate) (PNIPAM‐co‐PDMA) grafted onto sodium alginate (NaAlg) as a biocompatible polymer and iron oxide nanoparticles (ION) as nanometric base (PND/ION‐NG). This was then added into a solution of PDMA grafted onto NaAlg. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermal and magnetic responsivity was fabricated. The synthesized samples were fully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy‐dispersive X‐ray analysis, vibrating sample magnetometry and atomic force microscopy. A mechanism for the formation of PNIPAM‐co‐PDMA/NaAlg‐ION nanogel–PDMA/NaAlg‐ION hydrogel and PND/ION nanogel is suggested. Swelling capacity was measured at various temperatures (25 to 45 °C), pH values (from 2 to 11) and magnetic field and under load (0.3 psi) and the dependence of swelling properties of the nanogel–hydrogel nanocomposite on these factors was well demonstrated. The release rate of doxorubicin hydrochloride (DOX) as an anticancer drug was studied at different pH values and temperatures in the presence and absence of a magnetic field. The results showed that these factors have a high impact on drug release from this nanocomposite. The result showed that DOX release could be sustained for up to 12.5 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or nanogel alone (<1 day). The results indicated that the nanogel–hydrogel nanocomposite can serve as a novel nanocarrier for anticancer drug delivery. © 2019 Society of Chemical Industry     

Peak expiratory flow rate control chart in asthma care: chart construction and use in asthma care

We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families.     

Synthesis and characterization of hydroxyl terminated poly(butadiene)-g-poly(glycidyl azide) copolymer as a new energetic propellant binder

Summary Poly(glycidyl azide), PGA, was grafted onto Hydroxyl Terminated Poly(butadiene), HTPB, via free radical mechanism. PGA-macro azoinitator and HTPB polymer mixture was casted from solution and the polymer film was kept at 90°C for 4 hours. The grafted polymer was isolated from the product by fractional precipitation and characterized by NMR and FT-IR spectroscopy. Graft copolymer structure was also confirmed that volume ratio of nonsolvent to the solution of the graft copolymer was between those of corresponding homopolymers. TGA traces of the block polymers were containing two different maxima at 253°C (for PGA units) and 469°C (for HTPB units). Because of the incompatibility of the blocks, DSC curve showed two T_g's which belong to the related segments.     

High-Modulus Columns for Liquefaction Mitigation

This paper presents the performance of a shopping complex in Turkey where the soils were improved with jet-grout columns and preload fills and subjected to the 1999 Kocaeli Earthquake (M = 7.4). Under construction at the time of the earthquake, the Carrefour Shopping Center covers an area of 55,000?m2 and is founded on shallow footings, mats, and slabs-on-grade that rest on soft, saturated alluvial sediments consisting of clays, silts, and sands. High-modulus columns constructed by jet grouting were installed at close-to-moderate spacings to reduce anticipated static settlements in the clays and mitigate liquefaction in the sands. The site was subjected to a peak acceleration of approximately 0.2g during the earthquake. Grouting had been completed for about two-thirds of the site when the earthquake struck. Following the event, a field reconnaissance found stark contrast between the performance of the improved and unimproved sections. The jet-grout-treated areas suffered no apparent damage, whereas the unimproved sections of the complex, along with nearby untreated building sites, commonly suffered liquefaction-related settlements of up to 10 cm. This is the only case history known to the authors that documents the field performance of high-modulus columns used in this manner for liquefaction mitigation and direct instrumented measurement of liquefaction-induced settlements.     

The effects of cryogenic treatment on the toughness and tribological behaviors of eutectoid steel

Cryogenic treatment is a supplementary heat treatment usually applied after quenching. Its effects are permanent and this process affects the entire section. There have been many studies related to cryogenic treatment, most of which have been focused on tool steels. In the current study, a high-speed-train railway material was investigated, and different heat treatment processes were applied to the eutectoid steel. The effects of quenching and cryogenic treatment were investigated on the mechanical properties (toughness, hardness and wear). Four different structures were obtained with different heat treatment cycles: Pearlitic, tempered martensite, 12 hour cryo-treated tempered and 36 hour cryo-treated tempered. As a result of Charpy v-notch tests and hardness tests, cryogenic treatment was found to improve the toughness and hardness of quenched samples. The results of the ball-on-disc wear tests showed that the cryo-treated samples have better wear resistance than pearlitic and martensitic samples.     

Enhancing compatibility between poly(lactic acid) and thermoplastic starch using admicellar polymerization

An alternative method to improve the compatibility between poly(lactic acid) (PLA) and cassava starch (CS) is proposed and investigated. Admicellar polymerization is used to modify the surface of CS with poly(methyl methacrylate) (PMMA) in order to make it more hydrophobic and hence more compatible with PLA. The increased hydrophobicity of PMMA modified cassava starch (MS) is validated by contact angle measurement. Results from iodine test, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) confirm the formation of PMMA film on MS surface. Mechanical properties of PLA‐CS and PLA‐MS blends are investigated to compare their compatibility. Noticeable improvements in blend tensile strength and elongation at break evidently show that MS is more hydrophobic as well as more compatible with PLA than CS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43755.     

Organic–inorganic nanomatrix structure and properties of related naturally occurring rubbery macromolecules

The outstanding mechanical properties of soft materials i.e. natural rubber are partly due to the organic–inorganic nanomatrix structure because numerous organic microparticles are dispersed in a small amount of an inorganic nanomatrix composed of inorganic nanoparticles and organic macromolecules. Here we form an organic–inorganic nanomatrix using graft-copolymerization of a vinyl monomer with an inorganic oxide precursor onto natural rubber particles with an average diameter of 1 μm dispersed in water. The inorganic oxide precursor is converted into inorganic oxide nanoparticles through hydrolysis and condensation, forming chemical linkages between natural rubber microparticles and inorganic oxide nanoparticles. Transmission electron microscopy indicates that the organic–inorganic nanomatrix is densely filled with inorganic oxide nanoparticles and the natural rubber microparticles are dispersed in the nanomatrix. This nanomatrix composite realizes both energetic elasticity and entropic elasticity of a soft material, opening a novel field of building block chemistry with respect to a pair of organic microparticles and inorganic nanoparticles.     

Electrical and mechanical properties of BZT − xBCT lead-free piezoceramics

In this study, lead-free (1 − x)Ba(Zr_0.2Ti_0.8)O₃ − x(Ba_0.7Ca_0.3)TiO₃ compositions are synthesized via conventional solid oxide route, and the ceramics are fabricated with normal sintering in air. The effects of composition fluctuations on dielectric, piezoelectric, and mechanical properties are investigated. The phase structure and the microstructure are analyzed with X-ray diffraction and scanning electron microscopy. The best dielectric and piezoelectric properties of ε_r = 11 207 and d₃₃ = 330 pC/N were obtained for BZT−0.35BCT and BZT−0.5BCT ceramics, respectively. The mechanical behavior—in terms of Vickers hardness and compressive and flexural strengths—was investigated, and the best mechanical behavior was found in the vicinity of the phase transition boundary with x values between 0.5 and 0.6.     

Using statistical process control charts for the continual improvement of asthma care

BACKGROUND: Home monitoring of lung function using simple, inexpensive tools to measure peak expiratory flow rate (PEFR) has been possible since the 1970s. Yet although current national and international guidelines recommend monitoring of PEFRs via traditional run charts, their use by both patients and physicians remains low. The role of statistical process control (SPC) theory and charts in the serial monitoring of lung function at home were explored and applied to the direct care of patients with asthma. The method represents an integration of collective professional and improvement knowledge with the related disciplines of continual improvement, SPC, system thinking/system dynamics, paradigms, and the learning community/organization. CASE STUDIES: Use of PEFR control charts for four patients cared for at the Asthma-Allergy Clinic and Research Center (Shreveport, La) is described. The key to good asthma control is the ability to optimize lung function by reducing the variation between serial lung function measurements and thereby generate a safe range of function. Knowledge of the type of variation (special cause or common cause) in the system helps in focusing clinical decision making. Case 4, an 11-year-old boy, for example, shows how control charts were used to learn the effects of a new inhaled corticosteroid. Comparison of the last 14 days of baseline and the last 14 days of open label use of the inhaled corticosteroid showed an obvious improvement in actual PEFR values--which a run chart or comparison of means would have easily demonstrated. The control chart showed that this child's care process at baseline was functionally at risk for severe asthma (46% personal best) and that the effect of the new medication not only elevated the mean function but shifted the range of function from 46%-72% personal best to 78%-102% personal best. At this new range of function the patient's system of care was not capable of delivering values that are at risk for severe asthma. Unless the range of function the change in care is capable of producing is specifically quantitated, misinterpretation of improvement data can occur. DISCUSSION: Developing the concept of the PEFR control chart involved examining and challenging traditional mental models for monitoring PEFR at home in the care of asthma, acquiring a better understanding of the workings of dynamic systems and with system thinking, and sharing what was learned with patients and seeking their input. CONCLUSIONS: The PEFR control chart employs an interesting statistical platform that enables the integration of knowledge of serial measurements and knowledge of the variation between those measurements into a tool with which to better assess the asthma care process being followed. This tool provides clinical insights, practical knowledge, and opportunities unavailable to patients and physicians via traditional PEFR charting.     

ESR studies of molecular motions at the interphase region of a blendlike polymeric material

The molecular motions of spin probes at the interphase region of poly(methyl methacrylate) particles sterically stabilized by polyisobutylene (PIB) were studied by ESR spectroscopy. The correlation times (τ) were measured by using the methods of Freed and Kivelson. Activation energies for different modes of motion were calculated at wide temperature range between ?140 and 140°C. Viscosities were estimated in methanol saturated PIB channels in the polymer particles. © 1994 John Wiley & Sons, Inc.