A family of multi-responsive nanogels with different compositions and crosslinking degrees have been prepared by the miniemulsion copolymerization of monomethyl oligo(ethylene glycol) acrylate (OEGA) ...and an ortho ester-containing acrylic monomer, 2-(5,5-dimethyl-1,3-dioxan-2-yloxy) ethyl acrylate (DMDEA), with bis(2-acryloyloxyethyl) disulfide (BADS) as a crosslinker. These nanogels are thermoresponsive and labile in the weakly acidic or reductive environments. The thermoresponsive behaviors, acid-triggered hydrolysis, and reduction-induced degradation of these nanogels were studied by means of dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicate that the volume phase transition temperature (VPTT), thermally induced deswelling ratio, and acid-triggered swelling ratio of the nanogels are closely relevant to their compositions and crosslinking degrees. Although these nanogels could be reductively disrupted by dithiothreitol (DTT), single polymer chains with sizes smaller than 20
nm were not detected by DLS. This is probably due to the existence of some unbreakable linkages formed by chain transfer to the disulfide bond during the radical polymerization. These nanogels are capable of encapsulating hydrophobic compounds. The loading capability of the nanogels for Nile Red (NR), paclitaxel (PTX), and doxorubicin (DOX), and the release behaviors of the drug-loaded nanogels were investigated by UV–vis spectrometry and HPLC. As expected, drug release can be greatly accelerated by a cooperative effect of both acid-triggered hydrolysis and DTT-induced degradation. Finally, the PTX-loaded nanogels exhibit a concentration-dependent toxicity to MCF-7 cells while the intact unloaded nanogels are non-toxic, thereby they may be used as potential carriers for hydrophobic anticancer drugs.
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For biological synapses, high sensitivity is crucial for transmitting information quickly and accurately. Compared to biological synapses, memristive ones show a much lower sensitivity to electrical ...stimuli since much higher voltages are needed to induce synaptic plasticity. Yet, little attention has been paid to enhancing the sensitivity of synaptic devices. Here, electrochemical metallization memory cells based on lightly oxidized ZnS films are found to show highly controllable memristive switching with an ultralow SET voltage of several millivolts, which likely originates from a two‐layer structure of ZnS films, i.e., the lightly oxidized and unoxidized layers, where the filament rupture/rejuvenation is confined to the two‐layer interface region several nanometers in thickness due to different ion transport rates in these two layers. Based on such devices, an ultrasensitive memristive synapse is realized where the synaptic functions of both short‐term plasticity and long‐term potentiation are emulated by applying electrical stimuli several millivolts in amplitude, whose sensitivity greatly surpasses that of biological synapses. The dynamic processes of memorizing and forgetting are mimicked through a 5 × 5 memristive synapse array. In addition, the ultralow operating voltage provides another effective solution to the relatively high energy consumption of synaptic devices besides reducing the operating current and pulse width.
Based on lightly oxidized sulfide films, an ultrasensitive memristive synapse is realized where the synaptic functions of both short‐term plasticity and long‐term potentiation are emulated by applying electrical stimuli several millivolts in amplitude, whose sensitivity greatly surpasses that of biological synapses.
We present a new composite catalyst system of highly defective graphene quantum dots (HDGQDs)-doped 1T/2H-MoS2 for efficient hydrogen evolution reactions (HER). The high electrocatalytic activity, ...represented by an overpotential of 136.9 mV and a Tafel slope of 57.1 mV/decade, is due to improved conductivity, a larger number of active sites in 1T-MoS2 compared to that in 2H-MoS2, and additional defects introduced by HDGQDs. High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were used to characterize both the 1T/2H-MoS2 and GQDs components while Fourier-transform infrared spectroscopy (FTIR) was employed to identify the functional groups on the edge and defect sites in the HDGQDs. The morphology of the composite catalyst was also examined by field emission scanning electron microscopy (FESEM). All experimental data demonstrated that each component contributes unique advantages that synergistically lead to the significantly improved electrocatalytic activity for HER in the composite catalyst system.
There has been so far no energo-environmental system, whose design is considered energy-wise as well as cleanliness-wise, put in practical use despite the fact that those systems would be of huge ...potential importance as disaster shelters for casualties and/or infectious disease patients, in particular, those of COVID-19. We have designed the energo-environmental system based on the 2-Dimensional PhotoRecepto-Conversion Scheme (2DPRCS) and Clean Unit System Platform (CUSP) technologies. We have demonstrated the energo-environmental system can be as clean as US 209D class 1000 or better, quite handily, in a couple of minutes. As for the solar-cell-based energy generation part, we have shown that the needed electric power could be generated using our original technology of the 2DPRCS by simulations, as the possible first application of casualties’ and patients’ highly clean rest-space that has monitoring ability of the status of those people including sleep assessment. This energo-environmental clean system would be realized with the implementation of 2DPRCS in the near future.
The overnight polysomnographic (PSG) recordings of patients were scored by an expert to diagnose sleep disorders. Visual sleep scoring is a time-consuming and subjective process. Automatic sleep ...staging methods can help; however, the mechanism and reliability of these methods are not fully understood. Therefore, experts often need to rescore the recordings to obtain reliable results. Here, we propose a human-computer collaborative sleep scoring system. It is a rule-based automatic sleep scoring method that follows the American Academy of Sleep Medicine (AASM) guidelines to perform an initial scoring. Then, the reliability level of each epoch is analyzed based on physiological patterns during sleep and the characteristics of various stage changes. Finally, experts would only need to rescore epochs with a low-reliability level. The experimental results show that the average agreement rate between our system and fully manual scorings can reach 90.42% with a kappa coefficient of 0.85. Over 50% of the manual scoring time can be reduced. Due to the demonstrated robustness and applicability, the proposed approach can be integrated with various PSG systems or automatic sleep scoring methods for sleep monitoring in clinical or homecare applications in the future.
An 8-channel closed-loop neural-prosthetic SoC is presented for real-time intracranial EEG (iEEG) acquisition, seizure detection, and electrical stimulation in order to suppress epileptic seizures. ...The SoC is composed of eight energy-efficient analog front-end amplifiers (AFEAs), a 10-b delta-modulated SAR ADC (DMSAR ADC), a configurable bio-signal processor (BSP), and an adaptive high-voltage-tolerant stimulator. A wireless power-and-data transmission system is also embedded. By leveraging T-connected pseudo-resistors, the high-pass (low-pass) cutoff frequency of the AFEAs can be adjusted from 0.1 to 10 Hz (0.8 to 7 kHz). The noise-efficiency factor (NEF) of the AFEA is 1.77, and the DMSAR ADC achieves an ENOB of 9.57 bits. The BSP extracts the epileptic features from time-domain entropy and frequency spectrum for seizure detection. A constant 30- μA stimulus current is delivered by closed-loop control. The acquired signals are transmitted with on-off keying (OOK) modulation at 4 Mbps over the MedRadio band for monitoring. A multi-LDO topology is adopted to mitigate the interferences across different power domains. The proposed SoC is fabricated in 0.18- μm CMOS and occupies 13.47 mm 2 . Verified on Long Evans rats, the proposed SoC dissipates 2.8 mW and achieves high detection accuracy (> 92%) within 0.8 s.
There have been a variety of constant on-time (COT) controllers for dc power converter applications reported in recent years 1-5 . In this paper, a novel adaptive quasi-constant on-time current-mode ...control scheme is proposed and implemented in buck converters. While preserving the advantages of the conventional COT current-mode converters, this scheme allows fast transient response to step-load that is a critical requirement of a computer load with smart management. A small-signal model of the proposed circuit is also developed. Experimental results are also provided. This scheme is well suited for the next-generation dc converters for power management central-processor-unit devices.
The long-term consequences of human umbilical cord-derived mesenchymal stem cell (UC-MSC) treatment for COVID-19 patients are yet to be reported. This study assessed the 1-year outcomes in patients ...with severe COVID-19, who were recruited in our previous UC-MSC clinical trial.
In this prospective, longitudinal, cohort study, 100 patients enrolled in our phase 2 trial were prospectively followed up at 3-month intervals for 1 year to evaluate the long-term safety and effectiveness of UC-MSC treatment. The primary endpoint was an altered proportion of whole-lung lesion volumes measured by high-resolution CT. Other imaging outcomes, 6 min walking distance (6-MWD), lung function, plasma biomarkers, and adverse events were also recorded and analyzed. This trial was registered with ClinicalTrials.gov (NCT04288102).
MSC administration improved in whole-lung lesion volume compared with the placebo with a difference of −10.8% (95% CI: −20.7%, −1.5%, p = 0.030) on day 10. MSC also reduced the proportion of solid component lesion volume compared with the placebo at each follow-up point. More interestingly, 17.9% (10/56) of patients in the MSC group had normal CT images at month 12, but none in the placebo group (p = 0.013). The incidence of symptoms was lower in the MSC group than in the placebo group at each follow-up time. Neutralizing antibodies were all positive, with a similar median inhibition rate (61.6% vs. 67.6%) in both groups at month 12. No difference in adverse events at the 1-year follow-up and tumor markers at month 12 were observed between the two groups.
UC-MSC administration achieves a long-term benefit in the recovery of lung lesions and symptoms in COVID-19 patients.
The National Key R&D Program of China, the Innovation Groups of the National Natural Science Foundation of China, and the National Science and Technology Major Project.
The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, ...{Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single‐crystal X‐ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4− ions, features a cage core composed of twelve vertex‐sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl− and NO3− were incorporated in the reaction instead of ClO4−, {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex‐sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage‐like {Gd38} can be dynamically converted into the barrel‐shaped {Gd48} upon Cl− and NO3− stimulus. To our knowledge, it is the first time that the linear M‐O‐M′ fashion and the unique μ8‐ClO4− mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg−1 K−1 and mJ cm−3 K−1 on account of the weak antiferromagnetic exchange, the high NGd/MW ratio (magnetic density), and the relatively compact crystal lattice (mass density).
The birdcage: Two novel nanoscale lanthanide hydroxide clusters, {Gd38} and {Gd48}, are reported. Moreover, the {Gd38} cage can be dynamically converted into the {Gd48} barrel upon Cl− and NO3− stimulus (see figure). Both complexes display large magnetocaloric effects due to the dominant weak antiferromagnetic interactions, the high NGd/MW ratio, and the relatively compact crystal lattice.
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