A 0.35 THz Extended Interaction Oscillator based on Overmoded and Bi-Periodic Structure

An improved topology of Extended interaction oscillators (EIO) is presented with enhanced efficiency at 0.35 THz. A bi-periodic ladder-type structure is used for optimizing the performance of the TM 31−2π mode operation, based on bi-periodic interaction gaps composed of staggered short and long slots. The bi-periodic interaction mechanism permits to operate the circuit with a standing-wave field between the π and 2π modes, thus providing the potential to combine the advantages of both π and 2π modes in terms of both coupling and output performance. The resulting transverse TM 31 operating mechanism exhibits a good agreement with the bi-periodic structure in terms of coupling performance, with the short slot length positively correlated with the value of effective characteristic impedance M2R/Q . The circuit demonstrates attractive coupling and output characteristics by optimization of M2R/Q and Qe . A state-of-the-art value M2R/Q of 59.69 Ω and a moderate Qe of 2523.52 are achieved for a proposed eight-period ladder-type EIO. An RF power of 540 W is obtained with a 42.5 kV, 0.6 A sheet beam, with 2.1% electronic efficiency at 0.35 THz

Diffusion Tensor Imaging With Tract-Based Spatial Statistics Reveals White Matter Abnormalities in Patients With Vascular Cognitive Impairment

Purpose: The aim of this study was to evaluate microstructural changes of major white matter (WM) tracts in patients with vascular cognitive impairment (VCI).Method: Diffusion tensor imaging (DTI) data were obtained from 24 subjects with subcortical ischemic vascular disease (SIVD), including 13 subjects with VCI-no dementia (VCIND) and 11 subjects with normal cognition (as a control group). A tract-based spatial statistics approach was performed to investigate WM microstructure in VCIND by integrating multiple indices including fractional anisotropy (FA) and mean diffusivity (MD), which are intra-voxel metrics, and local diffusion homogeneity (LDH), which is an inter-voxel metric.Results: The VCIND group had decreased FA and increased MD values throughout widespread WM areas predominately in the corpus callosum, bilateral internal capsule/corona radiata/posterior thalamic radiation/inferior fronto-occipital fasciculus and right inferior/superior longitudinal fasciculus. There was a slight discrepancy between the distribution of areas with decreased FA and LDH. The FA, MD and LDH values were significantly correlated with cognitive test results. According to a WM tract atlas, 10 major tracts were identified as tracts of interest in which three diffusion metrics simultaneously differed between groups, including bilateral anterior thalamic radiation, forceps minor, right corticospinal tract, bilateral inferior fronto-occipital fasciculus, left inferior and superior longitudinal fasciculus, and bilateral uncinate fasciculus. Receiver operating characteristic (ROC) analysis demonstrated the feasibility of using diffusion metrics along the forceps minor and left anterior thalamic radiation for separating two groups.Conclusion: The results suggest WM microstructural abnormalities contribute to cognitive impairments in SIVD patients. DTI parameters may be potential biomarkers for detecting VCIND from SIVD

Molecular Programming of Biodegradable Nanoworms via Ionically Induced Morphology Switch toward Asymmetric Therapeutic Carriers

Engineering biodegradable nanostructures with precise morphological characteristics is a key objective in nanomedicine. In particular, asymmetric (i.e., nonspherical) nanoparticles are desirable due to the advantageous effects of shape in a biomedical context. Using molecular engineering, it is possible to program unique morphological features into the self-assembly of block copolymers (BCPs). However, the criteria of biocompatibility and scalability limit progress due to the prevalence of nondegradable components and the use of toxic solvents during fabrication. To address this shortfall, a robust strategy for the fabrication of morphologically asymmetric nanoworms, comprising biodegradable BCPs, has been developed. Modular BCPs comprising poly (ethylene glycol)-block-poly(caprolactone-gradient-trimethylene carbonate) (PEG−PCLgTMC), with a terminal chain of quaternary ammonium-TMC (PTMC-Q), undergo self-assembly via direct hydration into well-defined nanostructures. By controlling the solution ionic strength during hydration, particle morphology switches from spherical micelles to nanoworms (of varying aspect ratio). This ionically-induced switch is driven by modulation of chain packing with salts screening interchain repulsions, leading to micelle elongation. Nanoworms can be loaded with cytotoxic cargo (e.g., doxorubicin) at high efficiency, preferentially interact with cancer cells, and increase tumor penetration. This work showcases the ability to program assembly of BCPs and the potential of asymmetric nanosystems in anticancer drug delivery

Animal carcass- and wood-derived biochars improved nutrient bioavailability, enzyme activity, and plant growth in metal-phthalic acid ester co-contaminated soils: A trial for reclamation and improvement of degraded soils

Reclamation of degraded soils such as those with low organic carbon content and soils co-contaminated with toxic elements and phthalic acid esters (PAEs) is of great concern. Little is known about the efficiency of plantand animal-derived biochars for improving plant growth and physicochemical and biological properties of co-contaminated soils, particularly under low content of organic matter. Hence, a pot trial was carried out by growing pak choi (Brassica chinensis L.) to assess the influence of different doses (0, 0.5, 1, 2, and 4%) of animal (pig carcass) and wood (Platanus orientalis) derived biochars on soil properties, nutrient availabilities, plant growth, and soil enzyme activities in two soils containing low (LOC) and high (HOC) organic carbon contents and co-contaminated with di-(2-ethylhexyl) phthalic acid (DEHP) and cadmium (Cd). Biochar applications improved pH, salinity, carbon content, and cation exchange capacity of both soils. Addition of biochars significantly increased the bioavailability and uptake of phosphorus and potassium in the plants in both soils with greater effects from pig biochar than wood biochar. Biochar additions also significantly enhanced urease, sucrase, and catalase activities, but suppressed acid phosphatase activity in both soils. The impact of pig biochar was stronger on urease and acid phosphatase, while the wood biochar was more effective with sucrase and catalase activities. The biomass yield of pak choi was significantly increased after biochar addition to both soils, especially in 2% pig biochar treatment in the LOC soil. The positive response of soil enzymes activities and plant growth for biochar addition to the Cd and DEHP co-contaminated soils indicate that both biochars, particularly the pig biochar can mitigate the risk of these pollutants and prove to be eco-friendly and low-cost amendments for reclaiming these degraded soils

Adaptive polymersome nanoreactors

Adaptive polymersome systems have gained much interest in a wide variety of research fields, ranging from cell mimics to nanomedicine, because of their high stability, tuneable shape and size. Furthermore, polymersomes can be effectively transformed into nanoreactors via the incorporation of catalytic species. By employing polymersomes which are adaptive in structure and function the features of polymersome nanoreactors can be even further extended. In this review, we focus on recent impressive developments of smart polymersomes as functional nanoreactors with an emphasis on the type of adaptivity that is installed, which includes intrinsic permeability, stimuli‐responsiveness and self‐adaptivity. Moreover, particular attention is given to the utility of polymersome nanoreactors in vitro and in vivo, which paves the next step forward towards the engineering of artificial organelles as therapeutic materials

Adaptive polymeric assemblies for applications in biomimicry and nanomedicine

Dynamic and adaptive self-assembly systems are able to sense an external or internal (energy or matter) input and respond via chemical or physical property changes. Nanomaterials that show such transient behavior have received increasing interest in the field of nanomedicine due to improved spatiotemporal control of the nanocarrier function. In this regard, much can be learned from the field of systems chemistry and bottom-up synthetic biology, in which complex and intelligent networks of nanomaterials are designed that show transient behavior and function to advance our understanding of the complexity of living systems. In this Perspective, we highlight the recent advancements in adaptive nanomaterials used for nanomedicine and trends in transient responsive self-assembly systems to envisage how these fields can be integrated for the formation of next-generation adaptive stimuli-responsive nanocarriers in nanomedicine

Recent advances in permeable polymersomes:fabrication, responsiveness, and applications

Polymersomes are vesicular nanostructures enclosed by a bilayer-membrane self-assembled from amphiphilic block copolymers, which exhibit higher stability compared with their biological analogues (e.g. liposomes). Due to their versatility, polymersomes have found various applications in different research fields such as drug delivery, nanomedicine, biological nanoreactors, and artificial cells. However, polymersomes prepared with high molecular weight components typically display low permeability to molecules and ions. It hence remains a major challenge to balance the opposing features of robustness and permeability of polymersomes. In this review, we focus on the design and strategies for fabricating permeable polymersomes, including polymersomes with intrinsic permeability, the formation of nanopores in the membrane bilayers by protein insertion, and the construction of stimuli-responsive polymersomes. Then, we highlight the applications of permeable polymersomes in the fields of biomimetic nanoreactors, artificial cells and organelles, and nanomedicine, to underline the challenges in the development of polymersomes as soft matter with biomedical utilities.</p