Magnetic nanoparticles, which exhibit a variety of unique magnetic phenomena that are drastically different from those of their bulk counterparts, are garnering significant interest since these ...properties can be advantageous for utilization in a variety of applications ranging from storage media for magnetic memory devices to probes and vectors in the biomedical sciences. In this Account, we discuss the nanoscaling laws of magnetic nanoparticles including metals, metal ferrites, and metal alloys, while focusing on their size, shape, and composition effects. Their fundamental magnetic properties such as blocking temperature (T b), spin life time (τ), coercivity (H c), and susceptibility (χ) are strongly influenced by the nanoscaling laws, and as a result, these scaling relationships can be leveraged to control magnetism from the ferromagnetic to the superparamagnetic regimes. At the same time, they can be used in order to tune magnetic values including H c, χ, and remanence (M r). For example, life time of magnetic spin is directly related to the magnetic anisotropy energy (K u V) and also the size and volume of nanoparticles. The blocking temperature (T b) changes from room temperature to 10 K as the size of cobalt nanoparticles is reduced from 13 to 2 nm. Similarly, H c is highly susceptible to the anisotropy of nanoparticles, while saturation magnetization is directly related to the canting effects of the disordered surface magnetic spins and follows a linear relationship upon plotting of m s 1/3 vs r −1. Therefore, the nanoscaling laws of magnetic nanoparticles are important not only for understanding the behavior of existing materials but also for developing novel nanomaterials with superior properties. Since magnetic nanoparticles can be easily conjugated with biologically important constituents such as DNA, peptides, and antibodies, it is possible to construct versatile nano−bio hybrid particles, which simultaneously possess magnetic and biological functions for biomedical diagnostics and therapeutics. As demonstrated in this Account, nanoscaling laws for magnetic components are found to be critical to the design of optimized magnetic characteristics of hybrid nanoparticles and their enhanced applicability in the biomedical sciences including their utilizations as contrast enhancement agents for magnetic resonance imaging (MRI), ferromagnetic components for nano−bio hybrid structures, and translational vectors for magnetophoretic sensing of biological species. In particular, systematic modulation of saturation magnetization of nanoparticle probes is important to maximize MR contrast effects and magnetic separation of biological targets.
The preparation of 2D layered SnS2 nanoplates with nanoscale lateral confinement (less than 150 nm) is described (see figure). Their unique nanoscale characteristics, including finite lateral 2D ...morphology, make the discharge capacity of Li ion batteries remarkably high‐almost close to the theoretical possible value.
Successful development of ultra-sensitive molecular imaging nanoprobes for the detection of targeted biological objects is a challenging task. Although magnetic nanoprobes have the potential to ...perform such a role, the results from probes that are currently available have been far from optimal. Here we used artificial engineering approaches to develop innovative magnetic nanoprobes, through a process that involved the systematic evaluation of the magnetic spin, size and type of spinel metal ferrites. These magnetism-engineered iron oxide (MEIO) nanoprobes, when conjugated with antibodies, showed enhanced magnetic resonance imaging (MRI) sensitivity for the detection of cancer markers compared with probes currently available. Also, we successfully visualized small tumors implanted in a mouse. Such high-performance, nanotechnology-based molecular probes could enhance the ability to visualize other biological events critical to diagnostics and therapeutics.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have been reported to exhibit immature embryonic or fetal cardiomyocyte-like phenotypes. To enhance the maturation of hESC-CMs, we ...identified a natural steroidal alkaloid, tomatidine, as a new substance that stimulates the maturation of hESC-CMs. Treatment of human embryonic stem cells with tomatidine during cardiomyocyte differentiation stimulated the expression of several cardiomyocyte-specific markers and increased the density of T-tubules. Furthermore, tomatidine treatment augmented the number and size of mitochondria and enhanced the formation of mitochondrial lamellar cristae. Tomatidine treatment stimulated mitochondrial functions, including mitochondrial membrane potential, oxidative phosphorylation, and ATP production, in hESC-CMs. Tomatidine-treated hESC-CMs were more sensitive to doxorubicin-induced cardiotoxicity than the control cells. In conclusion, the present study suggests that tomatidine promotes the differentiation of stem cells to adult cardiomyocytes by accelerating mitochondrial biogenesis and maturation and that tomatidine-treated mature hESC-CMs can be used for cardiotoxicity screening and cardiac disease modeling.
Two-Dimensional Nanosheet Crystals Seo, Jung-wook; Jun, Young-wook; Park, Seung-won ...
Angewandte Chemie (International ed.),
01/2007, Letnik:
46, Številka:
46
Journal Article
Recenzirano
Roll model: A new “shape‐transformation” concept (see picture) that proceeds through a rolling out of 1D tungsten oxide nanorods for the fabrication of laterally confined 2D WS2 nanosheet crystals ...has been developed. The resulting 2D WS2 nanosheet crystals show a significantly enhanced discharge capacity for applications in lithium ion batteries owing to their 2D nanoscale characteristics.
Identifying the lung carcinoma subtype in small biopsy specimens is an important part of determining a suitable treatment plan but is often challenging without the help of special and/or ...immunohistochemical stains. Pathology image analysis that tackles this issue would be helpful for diagnoses and subtyping of lung carcinoma. In this study, we developed AI models to classify multinomial patterns of lung carcinoma; ADC, LCNEC, SCC, SCLC, and non-neoplastic lung tissue based on convolutional neural networks (CNN or ConvNet). Four CNNs that were pre-trained using transfer learning and one CNN built from scratch were used to classify patch images from pathology whole-slide images (WSIs). We first evaluated the diagnostic performance of each model in the test sets. The Xception model and the CNN built from scratch both achieved the highest performance with a macro average AUC of 0.90. The CNN built from scratch model obtained a macro average AUC of 0.97 on the dataset of four classes excluding LCNEC, and 0.95 on the dataset of three subtypes of lung carcinomas; NSCLC, SCLC, and non-tumor, respectively. Of particular note is that the relatively simple CNN built from scratch may be an approach for pathological image analysis.
The enhanced photocatalytic effects of TiO2 nanoparticles for biomedical applications are presented. The synthesis of water‐soluble single‐crystalline TiO2 nanoparticles (see image) through surface ...modifications and their enhanced photocatalytic effects for skin‐cancer cell therapeutics compared to those of commercially available TiO2 nanoparticles are also demonstrated.
Background and Aims Preoperative biliary drainage (PBD) with stent placement has been commonly used for patients with malignant biliary obstruction. In PBD, the placement of fully covered ...self-expandable metal stents (FCSEMSs) may provide better patency duration and a lower incidence of cholangitis compared with plastic stents. We aimed to evaluate which type of stent showed better outcomes in PBD. Methods In this multicenter, prospective randomized trial, we compared PBD with FCSEMSs versus plastic stents in 86 patients with malignant biliary obstruction between January 2012 and December 2014. Patients with obstructive jaundice were randomly assigned to undergo PBD either with plastic stents or FCSEMS placement. Results Baseline characteristics were not significantly different between the 2 groups. Endoscopic stent placement was technically successful in all patients. Procedure-related adverse events were not significantly different between the 2 groups (plastic vs FCSEMS group; 16.3% vs 16.3%, P = 1.0). Reintervention was required in 16.3% of the plastic stent group and 14.0% of the FCSEMS group ( P = .763). The interval to surgery after PBD (plastic vs FCSEMS group; 14.2 ± 8.3 vs 12.3 ± 6.9 days, P = .426) was not significantly different between groups. Surgery-related adverse events occurred in 43.6% of the plastic stent group and 40.0% of the FCSEMS group ( P = .755). Conclusions In patients with resectable malignant biliary obstruction, the outcomes of PBD with plastic stents and FCSEMSs were similar. Considering the cost-effectiveness, PBD with plastic stents may be preferable to FCSEMS placement. (Clinical trial registration number: NCT01789502 .)
Unmanned aerial vehicles (UAVs) have been employed to perform aerial surveys in many industries owing to their versatility, relatively low cost, and efficiency. Ground control points (GCPs) are used ...for georeferencing to ensure orthophoto geolocation/positioning accuracy. In this study, we investigate the impact of the number and distribution of GCPs on the accuracy of orthophoto production based on images acquired by UAVs. A test site was selected based on regulatory requirements, and several scenarios were developed considering the specifications of the UAVs used in this study. The locations of GCPs were varied to obtain the results. Based on the results obtained for different numbers of GCPs per unit area and distribution of GCPs, it is shown that UAV-based platforms can be more extensively utilized in a range of applications. The findings of this study will significantly impact the development process of GCP automation algorithms and enable a more cost-effective approach when determining target sites for UAV-based orthophoto production.
Ultrathin Zirconium Disulfide Nanodiscs Jang, Jung-tak; Jeong, Sohee; Seo, Jung-wook ...
Journal of the American Chemical Society,
05/2011, Letnik:
133, Številka:
20
Journal Article
Recenzirano
We present a colloidal route for the synthesis of ultrathin ZrS2 (UT-ZrS2) nanodiscs that are ∼1.6 nm thick and consist of approximately two unit cells of S–Zr–S. The lateral size of the discs can be ...tuned to 20, 35, or 60 nm while their thickness is kept constant. Under the appropriate conditions, these individual discs can self-assemble into face-to-face-stacked structures containing multiple discs. Because the S–Zr–S layers within individual discs are held together by weak van der Waals interactions, each UT-ZrS2 disc provides spaces that can serve as host sites for intercalation. When we tested UT-ZrS2 discs as anodic materials for Li+ intercalation, they showed excellent nanoscale size effects, enhancing the discharge capacity by 230% and greatly improving the stability in comparison with bulk ZrS2. The nanoscale size effect was especially prominent for their performance in fast charging/discharging cycles, where an 88% average recovery of reversible capacity was observed for UT-ZrS2 discs with a lateral diameter of 20 nm. The nanoscale thickness and lateral size of UT-ZrS2 discs are critical for fast and reliable intercalation cycling because those dimensions both increase the surface area and provide open edges that enhance the diffusion kinetics for guest molecules.
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