Stimuli-responsive behaviors of flexible metal-organic frameworks (MOFs) make these materials promising in a wide variety of applications such as gas separation, drug delivery, and molecular sensing. ...Considerable efforts have been made over the last decade to understand the structural changes of flexible MOFs in response to external stimuli. Uniform pore deformation has been used as the general description. However, recent advances in synthesizing MOFs with non-uniform porous structures, i.e. with multiple types of pores which vary in size, shape, and environment, challenge the adequacy of this description. Here, we demonstrate that the CO
-adsorption-stimulated structural change of a flexible MOF, ZIF-7, is induced by CO
migration in its non-uniform porous structure rather than by the proactive opening of one type of its guest-hosting pores. Structural dynamics induced by guest migration in non-uniform porous structures is rare among the enormous number of MOFs discovered and detailed characterization is very limited in the literature. The concept presented in this work provides new insights into MOF flexibility.
This paper presents the conceptual design of a W-band high-harmonic gyrotron oscillator with a permanent magnet system. Mode selection, cavity design, beam-wave interaction calculations, ...electron-optical system, and quasi-optical mode converter output system are described. The gyrotron operates at the third harmonic of the electron cyclotron frequency with the beam interacting with a TE 02 circular electric mode. The permanent magnet system provided the maximum axial magnetic field of ~ 1.19 T in the cavity region of the gyrotron. In the simulations, an output power of 14 kW has been obtained at a beam voltage of 40 kV with beam current of 3 A, corresponding to an efficiency of 11.7% through optimizing system parameters.
Three series of functionalized coumarin compounds were designed and prepared as cholinesterase (AChE and BuChE) inhibitors. The biological profile against AChE and BuChE of the prepared compounds was ...determined. Compound
7b exhibited a mixed-type of AChE inhibitor with IC
50 value for the AChE inhibition of 0.19
±
0.01 μM and a high selectivity for AChE/BuChE, and compound
6b acted as non-competitive AChE inhibitor with IC
50 value of 0.43
±
0.02 μM. Structure–activity relationships (SARs) of prepared compounds were discussed.
Given advanced age, comorbidities, and immune dysfunction, chronic lymphocytic leukemia (CLL) patients may be at particularly high risk of infection and poor outcomes related to coronavirus disease ...2019 (COVID-19). Robust analysis of outcomes for CLL patients, particularly examining effects of baseline characteristics and CLL-directed therapy, is critical to optimally manage CLL patients through this evolving pandemic. CLL patients diagnosed with symptomatic COVID-19 across 43 international centers (n = 198) were included. Hospital admission occurred in 90%. Median age at COVID-19 diagnosis was 70.5 years. Median Cumulative Illness Rating Scale score was 8 (range, 4-32). Thirty-nine percent were treatment naive ("watch and wait"), while 61% had received ≥1 CLL-directed therapy (median, 2; range, 1-8). Ninety patients (45%) were receiving active CLL therapy at COVID-19 diagnosis, most commonly Bruton tyrosine kinase inhibitors (BTKi's; n = 68/90 76%). At a median follow-up of 16 days, the overall case fatality rate was 33%, though 25% remain admitted. Watch-and-wait and treated cohorts had similar rates of admission (89% vs 90%), intensive care unit admission (35% vs 36%), intubation (33% vs 25%), and mortality (37% vs 32%). CLL-directed treatment with BTKi's at COVID-19 diagnosis did not impact survival (case fatality rate, 34% vs 35%), though the BTKi was held during the COVID-19 course for most patients. These data suggest that the subgroup of CLL patients admitted with COVID-19, regardless of disease phase or treatment status, are at high risk of death. Future epidemiologic studies are needed to assess severe acute respiratory syndrome coronavirus 2 infection risk, these data should be validated independently, and randomized studies of BTKi's in COVID-19 are needed to provide definitive evidence of benefit.
Tumor necrosis factor alpha (TNF-α) is a multifunctional cytokine constitutively produced by adipose tissue that may mediate insulin resistance. Studies in Caucasian subjects have suggested that the ...G-308A transition in the 5′ region of the TNF-α gene may be associated with insulin resistance and obesity. These factors have been proposed to underlie the clustering of type 2 diabetes, hypertension, and dyslipidemia found in the metabolic syndrome, the prevalence of which is reaching epidemic proportions in Hong Kong Chinese. We investigated the association of this gene polymorphism with the components of the metabolic syndrome including the lipid profile, as well as with the indices of obesity and insulin resistance as measured by the insulin-glucose product, in 440 Chinese subjects (healthy 27.5% and overlapping groups with type 2 diabetes 54.1%, hypertension 38.8%, dyslipidemia 39.3%, or obesity 39.5%). The frequency of the mutant A allele was 7.4% in 121 healthy controls and 9.0% in the total population. The mutation was not associated with any component of the metabolic syndrome or with the prevalence of albuminuria and retinopathy in these subjects. Furthermore, there was no difference in anthropometric measures, insulin resistance, or lipid levels between subjects with the GG genotype and those with the mutant allele. In summary, the TNF-α gene G-308A polymorphism is unlikely to play an important role in the development of these disorders in this population.
A previously unknown rigid helical structure of zinc oxide consisting of a superlattice-structured nanobelt was formed spontaneously in a vapor-solid growth process. Starting from a single-crystal ...stiff nanoribbon dominated by the c-plane polar surfaces, an abrupt structural transformation into the superlattice-structured nanobelt led to the formation of a uniform nanohelix due to a rigid lattice rotation or twisting. The nanohelix was made of two types of alternating and periodically distributed long crystal stripes, which were oriented with their c axes perpendicular to each other. The nanohelix terminated by transforming into a single-crystal nanobelt dominated by nonpolar (Formula: see text) surfaces. The nanohelix could be manipulated, and its elastic properties were measured, which suggests possible uses in electromechanically coupled sensors, transducers, and resonators.
We report herein on the first commercial production of 32V high voltage Field-Drift MOSFET (FDMOS) embedded in HK/MG with RMG technology. To overcome the challenges encountered during the RMG ...process, a recessed structure with a specifically designed poly gate patterning was developed. By using the new scheme, the devices can prevent metal gate disruptions. By comparison with the traditional devices in poly/SiON technology, the recessed devices can maintain good performance without degradation. Some extra benefits are obtained with the scheme by 4 V improvement of gate dielectric breakdown. This approach can provide technological mass production techniques and reliable device characteristics for future PMIC and display driver ICs applications.
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