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Left atrial (LA) functional analysis has an established role in assessing left ventricular diastolic function. The current standard echocardiographic parameters used to study left ventricular diastolic function include pulsed-wave Doppler mitral inflow analysis, tissue Doppler imaging measurements, and LA dimension estimation. However, the above-mentioned parameters do not directly quantify LA performance. Deformation studies using strain and strain-rate imaging to assess LA function were validated in previous research, but this technique is not currently used in routine clinical practice. This review discusses the history, importance, and pitfalls of strain technology for the analysis of LA mechanics.

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Polyelectrolyte-polyelectrolyte complexes/multiwall carbon nanotubes (PECs/MWCNTs) nanocomposites have not been prepared until now because PECs are generally insoluble and infusible. In this work, solution-processable PEC/MWCNT nanocomposites and their membranes were prepared by in situ incorporation of MWCNTs into bulk PECs. The ionic complexation between poly(diallyldimethylammonium chloride) (PDDA) and sodium carboxymethyl cellulose (CMCNa) in the presence of MWCNTs was followed by z potential and optical transmittance measurements. Structures of PEC/MWCNT nanocomposites were characterized by FT-IR, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). It is found that MWCNTs are encapsulated by a layer of PEC and dispersed in a PEC matrix mainly on a single nanotube level. Mechanical properties of the nanocomposite membrane loaded with 7 wt% MWCNTs are greatly improved, showing 2.6 times higher tensile strength and 1.8 times higher modulus as compared with that of the pristine PEC. PEC/MWCNT nanocomposite membranes also display very high performance in pervaporation dehydration of isopropanol. This high pervaporation performance is reproducible with cycling feed temperatures and stable with increasing operation time up to 20 days.

Ultrafine ruthenium nanoparticles (NPs) within the mesopores of the SBA-15 have been successfully prepared by using a “double solvents” method, in which n-hexane is used as a hydrophobic solvent and RuCl3 aqueous solution is used as a hydrophilic solvent. After the impregnation and reduction processes, the samples were characterized by XRD, TEM, EDX, XPS, N2 adsorption-desorption, and ICP techniques. The TEM images show that small sized Ru NPs with an average size of 3.0 ± 0.8 nm are uniformly dispersed in the mesopores of SBA-15. The as-synthesized Ru@SBA-15 nanocomposites (NCs) display exceptional catalytic activity for hydrogen generation by the hydrolysis of ammonia borane (NH3BH3, AB) and hydrazine borane (N2H4BH3, HB) at room temperature with the turnover frequency (TOF) value of 316 and 706 mol H2 (mol Ru min)−1, respectively, relatively high values reported so far for the same reaction. The activation energies (Ea) for the hydrolysis of AB and HB catalyzed by Ru@SBA-15 NCs are measured to be 34.8 ± 2 and 41.3 ± 2 kJ mol−1, respectively. Moreover, Ru@SBA-15 NCs also show satisfied durable stability for the hydrolytic dehydrogenation of AB and HB, respectively.

Highly intergrown mordenite membranes were rapidly prepared on seeded aluminum supports by microwaveassisted synthesis. Both the thicknesses of the zeolite layer and the sizes of the zeolite crystals of the mordenite membranes were highly dependent on the synthesis time. With a SiO 2 :0.08Al 2 O 3 :0.2Na 2 O:0.1NaF:35H 2 O precursor synthesis gel, a compact and 0.75 μm thick mordenite crystal layer was successfully prepared on the aluminum support at 170 °C for 3 h. The as-synthesized mordenite membrane exhibited excellent water perm-selectivity and long-term stability for dehydration of alcohol/water, acetic acid/water, and acetic acid/ethanol/water/ethyl ester mixtures by pervaporation. For dehydration of 90 wt % acetic acid/water solution, the corresponding flux and separation factor (water over acetic acid) of the membrane remained at 0.44 kg•m −2 •h −1 and 2300, respectively, at 75 °C even after 59 days of immersion.

A continuous intergrown silicalite zeolite membrane with high pervaporation (PV) performance was successfully prepared on seeded tubular mullite supports in ultradilute solution with a H 2 O/SiO 2 ratio of 800 and an inexpensive template of tetrapropylammonium bromide (TPABr) instead of tetrapropylammonium hydroxide (TPAOH). Several parameters were systematically investigated to evaluate their influence on crystallization and PV performance of the membranes, including the H 2 O/SiO 2 ratio, template type, alkalinity, synthesis temperature, crystallization time, and silica source. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and PV tests were used to characterize the as-synthesized membranes. The crystal growth and separation quality of the silicalite membranes were very sensitive to the H 2 O/SiO 2 ratio and alkalinity in the precursor solution and synthesis temperature. Under the optimized synthesis conditions, the outer surface of support was fully covered with well-intergrown silicalite zeolite layer to form the zeolite membrane. For silicalite membrane prepared with the typical molar composition of synthesis solutions of 1SiO 2 /0.1TPABr/0.2TPAOH/800H 2 O at 180 °C for 16 h, the flux and separation factor are achieved to 1.91 kg•m −2 •h −1 and 66 for a 5 wt % ethanol/water mixture at 60 °C, respectively. Moreover, the membrane prepared with pure TPABr template instead of TPAOH in ultradilute solution also showed the high PV performance with the flux of 1.77 kg•m −2 •h −1 and separation factor of 63 under the same tests conditions. Due to the utilization of ultradilute precursor and cheap organic template to prepare the silicalite membrane on cheap mullite supports with high PV performance, the present developed technique could reduce the chemical consumption and decrease the costs of membrane toward an organic/water mixture separation.

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