Tracking the Fate of Porous Silicon Nanoparticles Delivering a Peptide Payload by Intrinsic Photoluminescence Lifetime

A nanoparticle system for systemic delivery of therapeutics is described, which incorporates a means of tracking the fate of the nanocarrier and its residual drug payload in vivo by photoluminescence (PL). Porous silicon nanoparticles (PSiNPs) containing the proapoptotic antimicrobial peptide payload, _D[KLAKLAK]₂, are monitored by measurement of the intrinsic PL intensity and the PL lifetime of the nanoparticles. The PL lifetime of the PSiNPs is on the order of microseconds, substantially longer than the nanosecond lifetimes typically exhibited by conventional fluorescent tags or by autofluorescence from cells and tissues; thus, emission from the nanoparticles is readily discerned in the time‐resolved PL spectrum. It is found that the luminescence lifetime of the PSiNP host decreases as the nanoparticle dissolves in phosphate‐buffered saline solution (37 °C), and this correlates with the extent of release of the peptide payload. The time‐resolved PL measurement allows tracking of the in vivo fate of PSiNPs injected (via tail vein) into mice. Clearance of the nanoparticles through the liver, kidneys, and lungs of the animals is observed. The luminescence lifetime of the PSiNPs decreases with increasing residence time in the mice, providing a measure of half‐life for degradation of the drug nanocarriers.     

The use of acellular dermal matrix in immediate two-stage prosthetic breast reconstruction provides protection from postmastectomy radiation therapy: a clinicopathologic perspective

Although there is ample evidence showing that radiation therapy increases the risk of complications of breast reconstruction, the efficacy of human acellular dermal matrix (CGCryoDerm®) in immediate tissue expander breast reconstruction in the setting of postmastectomy radiation therapy has not been fully elucidated. In this study, we report our institutional experience with pertinent refined surgical technique, and determine whether acellular dermal matrices have a protective effect in this increasingly prevalent clinical setting. Twenty-six patients who underwent immediate two-stage breast reconstruction in the setting of postmastectomy radiation therapy with at least 2 years of follow-up were retrieved. Fifteen patents were reconstructed with ADM, whereas 11 patients were reconstructed without ADM. The occurrence of complications was assessed according to the reconstruction type (with ADM vs without ADM). Furthermore, in patients reconstructed with ADM (n?=?15), immunohistochemistry was performed to analyze the breast capsule with ADM compared with that without ADM in the same patient, according to the expression of alpha-smooth muscle actin (α-SMA). The occurrence of complications was significantly associated with the reconstruction type (with ADM vs. without ADM, p = 0.015). On the basis of the results of α-SMA staining, α-SMA+ myofibroblasts were relatively highly expressed throughout the breast capsule without ADM. On the contrary, α-SMA+ myofibroblasts present at the breast capsule adjacent to the ADM were scarce and irregularly scattered. Use of an acellular dermal matrix may be recommended to patients who are concerned about complications after immediate two-stage breast reconstruction in the setting of postmastectomy radiation therapy.     

Race Classification Using Deep Learning

Race classification is a long-standing challenge in the field of face image analysis. The investigation of salient facial features is an important task to avoid processing all face parts. Face segmentation strongly benefits several face analysis tasks, including ethnicity and race classification. We propose a race-classification algorithm using a prior face segmentation framework. A deep convolutional neural network (DCNN) was used to construct a face segmentation model. For training the DCNN, we label face images according to seven different classes, that is, nose, skin, hair, eyes, brows, back, and mouth. The DCNN model developed in the first phase was used to create segmentation results. The probabilistic classification method is used, and probability maps (PMs) are created for each semantic class. We investigated five salient facial features from among seven that help in race classification. Features are extracted from the PMs of five classes, and a new model is trained based on the DCNN. We assessed the performance of the proposed race classification method on four standard face datasets, reporting superior results compared with previous studies.     

Proxy-Based Hierarchical Distributed Mobility Management for Tactical Networks

An important requirement in a military domain is a highly reliable mobility management method, especially when components of the networks are moving in tactical network environments. To increase reliability, the mobility management technology of the tactical network should be able to reflect the characteristics of the tactical network, such as a limited environment, failure, and hierarchical unit structure. In this paper, we propose a proxy-based hierarchical distributed mobility management scheme, which is highly focused on tactical networks. Considering the characteristics of tactical networks, the proposed scheme is composed of the following: 1) a proxy-based method, 2) a distributed mobility management method that synchronizes a mobility database between entities, and 3) a method of managing mobility by dividing the tactical network into upper and lower layers. Mathematical analysis and modeling and simulation results demonstrate that the method outperforms the existing state-of-the-art method in overcoming entity failure, handover cost, and delay in tactical environments.     

Disclosing the Role of Defect-Engineered Metal–Organic Frameworks in Mixed Matrix Membranes for Efficient CO2 Separation: A Joint Experimental-Computational Exploration

Incorporation of defects in metal–organic frameworks (MOFs) offers new opportunities for manipulating their microporosity and functionalities. The so-called “defect engineering” has great potential to tailor the mass transport properties in MOF/polymer mixed matrix membranes (MMMs) for challenging separation applications, for example, CO₂ capture. This study first investigates the impact of MOF defects on the membrane properties of the resultant MOF/polymer MMMs for CO₂ separation. Highly porous defect-engineered UiO-66 nanoparticles are successfully synthesized and incorporated into a CO₂-philic crosslinked poly(ethylene glycol) diacrylate (PEGDA) matrix. A thorough joint experimental/simulation characterization reveals that defect-engineered UiO-66/PEGDA MMMs exhibit nearly identical filler–matrix interfacial properties regardless of the defect concentrations of their parental UiO-66 filler. In addition, non-equilibrium molecular dynamics simulations in tandem with gas transport studies disclose that the defects in MOFs provide the MMMs with ultrafast transport pathways mainly governed by diffusivity selectivity. Ultimately, MMMs containing the most defective UiO-66 show the most enhanced CO₂/N₂ separation performance—CO₂ permeability = 470 Barrer (four times higher than pure PEGDA) and maintains CO₂/N₂ selectivity = 41—which overcomes the trade-off limitation in pure polymers. The results emphasize that defect engineering in MOFs would mark a new milestone for the future development of optimized MMMs.     

Surface modification of polydimethylsiloxane (PDMS) induced proliferation and neural-like cells differentiation of umbilical cord blood-derived mesenchymal stem cells

Stem cell-based therapy has recently emerged for use in novel therapeutics for incurable diseases. For successful recovery from neurologic diseases, the most pivotal factor is differentiation and directed neuronal cell growth. In this study, we fabricated three different widths of a micro-pattern on polydimethylsiloxane (PDMS; 1, 2, and 4 microm). Surface modification of the PDMS was investigated for its capacity to manage proliferation and differentiation of neural-like cells from umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs). Among the micro-patterned PDMS fabrications, the 1 microm-patterned PDMS significantly increased cell proliferation and most of the cells differentiated into neuronal cells. In addition, the 1 microm-patterned PDMS induced an increase in cytosolic calcium, while the differentiated cells on the flat and 4 microm-patterned PDMS had no response. PDMS with a 1 microm pattern was also aligned to direct orientation within 10 degrees angles. Taken together, micro-patterned PDMS supported UCB-MSC proliferation and induced neural like-cell differentiation. Our data suggest that micro-patterned PDMS might be a guiding method for stem cell therapy that would improve its therapeutic action in neurological diseases.     

Indoline‐Based Molecular Engineering for Optimizing the Performance of Photoactive Thin Films

New indoline dyes ( RK‐1 – 4 ) were designed with a planar geometry and high molar extinction coefficient, which provided surprising power conversion efficiency (PCE) with a thin titanium dioxide film in dye‐sensitized solar cells (DSCs). They had a difference in only alkyl chain length. Despite the same molecular structure, the performance of the respective DSCs varied significantly. Investigating the dye adsorption processes and charge transfer kinetics, the alkyl chain length was determined to affect the dye surface coverage as well as the recombination between the injected photoelectrons and the oxidized redox mediators. When applied to the DSCs as a light harvester, RK‐3 with the dodecyl group exhibited the best photocurrent density, consequently achieving the best PCE of 9.1% with a 1.8 μm active and 2.5 μm scattering layer because of the most favorable charge injection. However, when increasing the active layer thickness, overall device performance deteriorated and the charge collection and regeneration played major roles for determining the PCE. Therefore, RK‐2 featuring the highest surface coverage and moderate alkyl chain length obtained the highest PCEs of 8.8% and 7.9% with 3.5 and 5.1 μm active layers, respectively. These results present a promising perspective of organic dye design for thin film DSCs.     

A 1.2 V 83 dB DR single‐ended input SC ΔΣ modulator including a large‐swing analog buffer for portable ECG applications

This study proposes a subsystem consisting of an analog buffer and a single‐ended input to a fully differential ΔΣ modulator to obtain low‐power consumption for portable electrocardiogram applications. With the proposed subsystem, the need for an inverting amplifier is avoided, and low‐power consumption is achieved. The ΔΣ modulator with a second order, 1 bit, and cascade of integrators feedforward structure consumes a low power, in which an inverting and a non‐inverting path implement a single‐ended input to fully‐differential signals. A double sampling technique is proposed for a digital‐to‐analog converter feedback circuit to reduce the effect of the reference voltage, reduce the amplifier requirements, and obtain low‐power consumption. Input‐bias and output‐bias transistors working in the weak‐inversion region are implemented to obtain an extremely large swing for the analog buffer. At a supply voltage of 1.2 V, signal bandwidth of 250 Hz, and sampling frequency of 128 kHz, the measurement results show that the modulator with a buffer achieves a 77 dB peak signal‐to‐noise‐distortion ratio, an effective‐number‐of‐bits of 12.5 bits, an 83 dB dynamic range, and a figure‐of‐merit of 156 dB. The total chip size is approximately 0.28 mm² with a standard 0.13 µm Complementary Metal‐Oxide‐Silicon (CMOS) process. Copyright © 2016 John Wiley & Sons, Ltd.