RESUMEN
Strong, lightweight, and shape-memory cellulose aerogels have great potential in multifunctional applications. However, achieving the integration of these features into a cellulose aerogel without harsh chemical modifications and the addition of mechanical enhancers remains challenging. In this study, a strong, lightweight, and water-stimulated shape-memory all-cellulose aerogel (ACA) is created using a combination strategy of partial dissolution and unidirectional freezing from bamboo. Benefiting from the firm architecture of cellulose microfibers bridging cellulose nanofibers /regenerated cellulose aggregated layers and the bonding of different cellulose crystal components (cellulose Iß and cellulose II), the ACA, with low density (60.74 mg cm-3 ), possesses high compressive modulus (radial section: 1.2 MPa, axial section: 0.96 MPa). Additionally, when stimulated with water, the ACA exhibits excellent shape-memory features, including highly reversible compression-resilience and instantaneous fold-expansion behaviors. As a versatile scaffold, ACA can be integrated with hydroxyapatite, carboxyl carbon nanotubes, and LiCl, respectively, via a simple impregnation method to yield functionalized cellulose composites for applications in thermal insulation, electromagnetic interference shielding, and piezoresistive sensors. This study provides inspiration and a reliable strategy for the elaborately structural design of functional cellulose aerogels endows application prospects in various multifunction opportunities.
RESUMEN
In this work, a strategy for hybrid treatment was proposed, aiming to present a hybrid impregnation agent including lignin-derived resin (LR) and surface-modified montmorillonite (GMMT) to treat fast-growing poplar wood. The treating agents could penetrate the wood, fill the cavities of the wood interior, and strengthen the cell wall structure. The optimal WPG of 36.2% was obtained upon the response surface methodology (RSM) at the conditions of 34% LR, 1.8% GMMT, 1.2 MPa impregnation pressure, and 99 min impregnation time. The density, water uptake (WU), modulus of rupture (MOR), modulus of elasticity (MOE), and compressive strength (CS) of the samples were tested to evaluate the enhancement of the physical and mechanical properties. In addition, these samples were investigated via cone calorimeter (CONE), Fourier Transform Infrared spectrometer (FTIR), and X-ray diffraction (XRD). The results showed that the density of the treated samples increased significantly up to 0.72 g/cm3. Compared with 134.8% of the control, the WU of the treated wood sample could decrease to 60.3%. In addition, the MOR and MOE of the resulting samples reached up to 131.8 MPa and 18.14 GPa, respectively, which were 62.3% and 77.7% higher than the control. Notably, the CS was 84.7 MPa with an increase of up to 94.7%. Moreover, the peak heat release rate (HRR) of the treated sample was obviously reduced to 231.33 kW/m2, a decrease of 17.5% compared to the control (271.71 kW/m2).
RESUMEN
Background: Amelioration of depression in patients with post-stroke depression (PSD) remains challenging. Objective: The primary vision was to explore the effect of transcranial magnetic stimulation (TMS) in combination with citalopram on patients with PSD. Methods: One hundred eligible patients who were diagnosed with PSD were recruited and randomly assigned to the control group (n = 50) or the TMS group (n = 50). The controls were given citalopram (10 mg/d for consecutive 8 weeks), while, in addition to citalopram, patients in the TMS group were also given TMS at 5 Hz once a workday for 8 weeks. The primary outcome was patient depression status as reflected by 17-item Hamilton Rating Scale for Depression (HAMD-17) score, and the secondary outcome was patient neuropsychological score determined by Mini-Mental State Examination (MMSE) and Wisconsin Card Sorting Test (WCST). Results: Patients treated with TMS in combination with citalopram had a drastic decrease in HAMD-17 score during treatment. Bigger changes in HAMD-17 score between baseline and 2 weeks as well as between baseline and 8 weeks in the TMS group were observed (P < 0.01). Patients in both groups had increased MMSE scores after treatment. Data of WCST revealed patients with TMS treatment completed more categories (P < 0.01) and had a lower RPP in comparison to patients in the control group (P < 0.0001). Additionally, TMS in combination with citalopram strikingly improved patients' MMSE scores when compared with those taking citalopram alone. Last, there was no striking difference in side effects between the two groups (P > 0.05). Conclusion: Our study found TMS in combination with citalopram is conducive to improving depression status and neuropsychological function, which holds great promise for treating PSD.
RESUMEN
Engineered biosynthetic pathways have the potential to produce high-value molecules from inexpensive feedstocks, but a key limitation is engineering enzymes with high activity and specificity for new reactions. Here, we developed a method for combining structure-based computational protein design with library-based enzyme screening, in which inter-residue correlations favored by the design are encoded into a defined-sequence library. We validated this approach by engineering a glucose 6-oxidase enzyme for use in a proposed pathway to convert D-glucose into D-glucaric acid. The most active variant, identified after only one round of diversification and screening of only 10,000 wells, is approximately 400-fold more active on glucose than is the wild-type enzyme. We anticipate that this strategy will be broadly applicable to the discovery of new enzymes for engineered biological pathways.
