Search

The characteristic NIR of copper sulfide nanocrystals (Cu2−xS NCs) assemblies based on the LSPR can be controlled by exploiting monovalent lithium ions through electrochemical methods.

Recent advances in the field of tissue engineering and regenerative medicine have contributed to the repair of damaged tissues and organs. Renal dysfunctions such as chronic kidney disease (CKD) are considered intractable owing to its cellular heterogeneity. In addition, the absence of definitive treatment options other than dialysis or kidney transplantation in advanced CKD. In this study, we investigated therapeutic effects of a three-dimensional (3D) bio-printed omentum patch as treatment source. Because omentum contains a lot of biological sources for immune regulation and tissue regeneration, it has been used in clinic for100 years. By using autologous tissue as a bio-ink, the patch could minimize the immune response. The mechanically micronized omentum without any additives became small enough to print, but the original components could be preserved. Then, the 3D printed omentum patch was transplanted under renal subcapsular layer in unilateral ureteral obstruction (UUO) rat model. After 14 days of patch transplantation, the kidneys were analyzed through bulk RNA sequencing and histopathological staining. From the results, decreased tubular injury was observed in the omentum patch group. In addition, the omentum patch significantly altered biological process of gene ontology such as fibrosis-related gene and growth factors. RNA sequencing confirmed the antifibrotic effect by inhibiting fibrosis-inducing mechanisms within PI3K-AKT and JAK-STAT pathways. In conclusion, the omentum patch showed the effect of antitubular injury and antifibrosis on UUO kidneys. In particular, the omentum patch is expected to protect the organ from further degeneration and loss of function by inhibiting the progression of fibrosis. The omentum patch can be a novel therapeutic option for renal dysfunction. Impact statement Many studies and clinical trials are being conducted to develop new treatments for kidney disease. However, there are no newly developed renal replacement therapies. In this study, we developed a new treatment that can ameliorate renal interstitial fibrosis using three-dimensional (3D) bio-printed autologous omentum patch. The 3D printer enables precise patch printing, and the bio-ink made of autologous tissue minimizes the immune response after transplantation. The whole kidneys were analyzed by RNA sequencing and histopathological staining 14 days after transplantation. From the results, the omentum patch had the effect of relieving tubular injury in the injured state. Also, the omentum patch significantly altered biological process of gene ontology. In particular, genes related to fibrosis were observed to be downregulated by the omentum patch. RNA sequencing confirmed that the antifibrotic effect was owing to inducing mechanisms of PI3K-AKT and JAK-STAT pathways. The findings reported in this study represent a significant advancement in the application of 3D bio-printer to damaged organ treatments, especially fibrosis-related diseases.

The hole density of individual copper sulfide nanocrystals (Cu2-xS NCs) is determined from the stoichiometric mismatch (x) between copper and sulfide atoms. Consequently, the electronic properties of the material vary over a range of x. To exploit Cu2-xS NCs in devices, assemblies of NCs are typically required. Herein, we investigate the influence of x, referred to as the stoichiometric doping effect, on the structural, optical, electrical, and thermoelectric properties of electronically coupled Cu2-xS NC assemblies. The doping process is done by immersing the solid NC assemblies into a solution containing a Cu(I) complex for different durations (0-10 min). As Cu+ gradually occupied the copper-deficient sites of Cu2-xS NCs, x could be controlled from 0.9 to less than 0.1. Consequently, the near-infrared (NIR) absorbance of Cu2-xS NC assemblies changes systematically with x. With increasing x, electrical conductivity increased and the Seebeck coefficient decreased systematically, leading to the maximal thermoelectric power factor from a film of Cu2-xS NCs at an optimal doping condition yielding x = 0.1. The physical characteristics of the Cu2-xS NC assemblies investigated herein will provide guidelines for exploiting this emerging class of nanocrystal system based on doping.

Exploiting the long-range polarizability of an electrolyte based on ion migration, electric double-layer transistors (EDLTs) can be constructed in an unconventional configuration; here, the gate electrode is placed coplanarly with the device channel. In this paper, we demonstrate the influence of the distance factors of the electrolyte layer on the operation of EDLTs with a coplanar gate. As the promptness of the electric double-layer formation depends on the distance between the channel and the gate, the dynamic characteristics of a remote-gated transistor degrade with long distances. To suppress this degradation, we suggest using multiple coplanar floating gates bridged through ionic dielectric layers. Unlike remotely gated EDLTs that utilize a single extended electrolyte layer, the devices with multiple segmented electrolyte layers operate effectively even when they are gated from a distance longer than 1 mm.

BACKGROUND AND AIMS Renal fibrosis is one of the pathological hallmarks of chronic kidney disease (CKD) that can further progress to end-stage renal diseases (ESRD). Haemodialysis and kidney transplantation are the only feasible treatments of ESRD. In this study, a new treatment with autologous omental tissue was assessed to delay the progression of renal fibrosis. The omental tissue, a fatty structure, has been widely used in surgical procedures due to its immunologic, angiogenic characteristics and anti-fibrotic factors that enhance tissue repairs, cell proliferation and regeneration in a damaged tissue. Finally, we hypothesized that 3D printed omental patch can prevent renal fibrosis and help regenerate the damaged kidney in the animal model. The 3D printing can print cells and extracellular matrix uniformly to promote cell survival and differentiation during transplantation. The printing also can adjust the patch stiffness, providing a suitable environment for kidney recovery. METHOD Animal models of CKD were randomly divided into four groups: (A) sham-operated, (B) sham-operated + omental patch, (C) unilateral ureteral obstruction (UUO)-operated (Control) and (D) UUO-operated + omental patch. Micronized omental tissue as bio-ink was 3D printed in the form of a regular patch deformation. Then, the 3D printed omental patch was transplanted subcapsular layer of the kidney. All of the patches used in those groups were transplanted after 3 days of modelling. Kidneys were assessed histologically [Masson's Trichrome (MT), Sirius Red], by immunohistochemistry (α-SMA), molecular work (Bulk RNA sequencing, western blot) after 2 weeks of transplantation. RESULTS Omental patch treated group has been shown histologically less tubulointerstitial fibrosis and tubule atrophy by MT, Sirius Red staining. Particularly, the TGF beta mRNA expression level of the 3D printed omental treated group was decreased in the kidney, whereas the HGF level was significantly increased. Also, in terms of western blotting, pro-inflammatory and renal fibrosis markers (TGF-b, α-SMA) were all decreased. Moreover, in bulk RNA sequencing, we confirmed that STAT 3 kidney repair pathway and TF-beta signalling. From all those assessments we suggest that the induction of myofibroblasts and collagen deposition are all inhibited in the omental patch treated kidney model. The autologous 3D omental patch can prevent tubular atrophy and decreased tubulointerstitial fibrosis and this further delays the progression of ESRD. CONCLUSION The study demonstrated that the omental patch delays fibrosis and repairs tubule structure in the damaged kidney by providing protective effects to kidney disease. These studies indicate the feasibility of the use of the autologous omental patch in chronic kidney disease therapeutic effects and new treatment of renal replacement therapy (RRT).

Colloidal quantum dots (QDs) stand at the forefront of a variety of photonic applications given their narrow spectral bandwidth and near-unity luminescence efficiency. However, integrating luminescent QD films into photonic devices without compromising their optical or transport characteristics remains challenging. Here we devise a dual-ligand passivation system comprising photocrosslinkable ligands and dispersing ligands to enable QDs to be universally compatible with solution-based patterning techniques. The successful control over the structure of both ligands allows the direct patterning of dual-ligand QDs on various substrates using commercialized photolithography (i-line) or inkjet printing systems at a resolution up to 15,000 pixels per inch without compromising the optical properties of the QDs or the optoelectronic performance of the device. We demonstrate the capabilities of our approach for QD-LED applications. Our approach offers a versatile way of creating various structures of luminescent QDs in a cost-effective and non-destructive manner, and could be implemented in nearly all commercial photonics applications where QDs are used.

Transmission-reflection terahertz spatial light modulator is introduced using electrically tunable dual-mode metamaterial. Simultaneous transmissive and reflective imaging technique for differential respective objects was demonstrated using single SLM with high accuracy compared to real object.

The hole density of individual copper sulfide nanocrystals (Cu

We present nonvolatile transistor memory devices that rely on the formation of electric double layer (EDL) at the semiconductor–electrolyte interface. The two critical functional components of the devices are the ion gel electrolyte and gold nanoparticles (NPs). The ion gel electrolyte contains ionic species for EDL formation that allow inducing charges in the semiconductor–electrolyte interface. The gold NPs inserted between the ion gel and the channel layer serve as trapping sites to the induced charges to store the electrical input signals. Two different types of gold NPs were used: one prepared using direct thermal evaporation and the other prepared using a colloidal process. The organic ligands attached onto the colloidal gold NPs prevented the escape of the trapped charges from the particles and thus enhanced the retention characteristics of the programmed/erased signals. The low-voltage-driven EDL formation resulted in a programmed/erased memory signal ratio larger than 103 from the nonvolatile ind...

An analytical model for the bulk trap charge-induced threshold voltage variation in the intrinsic channel MOSFET is presented. A new definition of the flat band voltage, the gate voltage necessary to nullify the gate charge, which is induced by the bulk charges, is introduced. With the newly defined flat band voltage based on the bulk charge sheet approximation, the analytical MOS equations are derived for both the intrinsic channel nanowire and planar MOSFETs. It is shown that the analytical models predict the device characteristics reasonably well, compared with the numerical device simulations. Also, the error induced by the charge sheet approximation is compared with the point charge, using the numerical simulation. The model will be useful to predict the threshold voltage variation of the intrinsic poly-Si, adopted by the modern 3-D nand flash memory cell transistors.

Recent attempts to employ colloidal semiconductor nanocrystals (NCs) as the sensitizing materials for hybrid NC–graphene phototransistors have provided a new effective photosensing platform. However, most of these devices are based on NCs containing either lead or cadmium, which would not be the most preferred material candidates for commercialization. Here, we demonstrate the use of colloidal Cu2–xSe NCs that do not contain lead or cadmium as the sensitizers for NCs–graphene hybrid visible phototransistors. Because the long olyelamine ligands originally attached on Cu2–xSe NCs are known to impede electronic process between NCs and graphene, the long ligands are replaced with short amines including octylamine, hexylamine, and butylamine. It is found that the NCs layer with shorter amine ligands yields a more prominent n-doping effect on graphene under illumination, which results in a systematic negative shift in Dirac voltage. More importantly, this leads to devices with larger photocurrent and larger lig...

As the number of wireless device deployments grows, it is desirable to share the highly limited wireless bandwidth efficiently and cooperatively. In WLAN, using a central controller for resource sharing and management is a common practice in mid-size and large-size network. However, in case of small businesses (i.e., restaurants, coffee shops, etc.), business owners cannot afford to obtain the controller. To realize the bandwidth sharing among Access Points (AP) in a distribute manner, seamless handoff of mobile devices (i.e., smartphones and tablets) between small-business owned Access Points (APs) via association control and maintain stable TCP connection are essential but quite challenging. This poster proposes a novel way to cooperatively share wireless resources among the APs. This includes an efficient association control between stations and APs, dedicated virtual access point per station, and tunneling support maintaining existing TCP connection after relocation to another AP.

This paper evaluates the classification of objects given their signal data via a simple convolutional neural network (CNN). Many of the signal processing neural networks involve sound frequency data or Doppler signatures that contain the characteristic features of each object. In this study, we use frequency-intensity data within range-time domain from a Frequency-Modulated Continuous-Wave (FMCW) radar to classify detected objects. The application of various data augmentation methods mitigated the scarcity of labeled data from our field experiments. Time stretching, frequency shifting and noise addition preserved the semantic information of each rangetime data, further improving the models ability to generalize. Modifications applied to our data, which is then converted into a low-level log-scaled mel-spectrogram representation, are learned by CNN models with a set of convolutional and max-pooling layers along with fully-connected layers and selective residual module. Based on our experiments, we conclude that raw radar data can be used for training CNNs for classification and thus can be used to classify a car, a human, and an UAV.

Metamaterial based electromagnetically induced transparency (EIT) analogue have attracted as an alternative way to realize exotic EIT applications such as slow light devices and biosensors. Researches on metamaterial EIT analogues have recently focused on the realization of active system to control the EIT-like spectral properties via various external stimuli, including optical, mechanical, and thermal methods. Graphene based EIT metamaterials have been also reported through the numerical analysis as an electrically controlled active system, but there are no experimental reports in terahertz regime due to insufficient electrical mobility and conductance variation range of practical graphene sheets to realize active EIT analogues. In our previous study, we had reported a new concept of metamaterial analogue to achieve EIT-like phenomena, in which cut-wire (CW) pair and pseudo complementary cut-wire (CCW) were orthogonally combined with each other, generating EIT-like properties by funneling terahertz waves through the pseudo-CCW hole in broad reflection resonance of CW pair. Since this extraordinary transmission could be easily suppressed with resistive conductors along the pseudo-CCW structure, we designed the ion-gel gated graphene lines on the center of meta-atom structures to control the funneling of terahertz waves. Controlling the electromagnetic funneling provided switchable EIT-like spectral properties of the proposed metamaterials and we numerically confirmed that the graphene lines successfully acted as switching materials, even if the lines were formed with practically achievable graphene films. Finally, we verified that the fabricated EIT metamaterials experimentally showed 54.9% of modulation depth and 1ps of group delay change at the transmission peak in terahertz range.

Active control of metamaterial properties is critical for advanced terahertz (THz) applications. However, the tunability of THz properties, such as the resonance frequency and phase of the wave, remains challenging. Here, a new device design is provided for extensively tuning the resonance properties of THz metamaterials. Unlike previous approaches, the design is intended to control the electrical interconnections between the metallic unit structures of metamaterials. This strategy is referred to as the molecularization of the meta-atoms and is accomplished by placing graphene bridges between the metallic unit structures whose conductivity is modulated by an electrolyte gating. Because of the scalable nature of the molecularization, the resonance frequency of the terahertz metamaterials can be tuned as a function of the number of meta-atoms constituting a unit metamolecule. At the same time, the voltage-controlled molecularization allows delicate control over the phase shift of the transmitted THz, without changing the high transmission of the materials significantly.