Model-based iterative reconstruction algorithms for low-dose X-ray computed tomography (CT) are computationally expensive. To address this problem, we recently proposed a deep convolutional neural ...network (CNN) for low-dose X-ray CT and won the second place in 2016 AAPM Low-Dose CT Grand Challenge. However, some of the textures were not fully recovered. To address this problem, here we propose a novel framelet-based denoising algorithm using wavelet residual network which synergistically combines the expressive power of deep learning and the performance guarantee from the framelet-based denoising algorithms. The new algorithms were inspired by the recent interpretation of the deep CNN as a cascaded convolution framelet signal representation. Extensive experimental results confirm that the proposed networks have significantly improved performance and preserve the detail texture of the original images.
Post-traumatic stress disorder (PTSD) is associated with abnormalities in the processing and regulation of emotion as well as cognitive deficits. This study evaluated the differential brain ...activation patterns associated with cognitive and emotional distractors during working memory (WM) maintenance for human faces between patients with PTSD and healthy controls (HCs) and assessed the relationship between changes in the activation patterns by the opposing effects of distraction types and gray matter volume (GMV). Twenty-two patients with PTSD and twenty-two HCs underwent T1-weighted magnetic resonance imaging (MRI) and event-related functional MRI (fMRI), respectively. Event-related fMRI data were recorded while subjects performed a delayed-response WM task with human face and trauma-related distractors. Compared to the HCs, the patients with PTSD showed significantly reduced GMV of the inferior frontal gyrus (IFG) (p < 0.05, FWE-corrected). For the human face distractor trial, the patients showed significantly decreased activities in the superior frontal gyrus and IFG compared with HCs (p < 0.05, FWE-corrected). The patients showed lower accuracy scores and slower reaction times for the face recognition task with trauma-related distractors compared with HCs as well as significantly increased brain activity in the STG during the trauma-related distractor trial was observed (p < 0.05, FWE-corrected). Such differential brain activation patterns associated with the effects of distraction in PTSD patients may be linked to neural mechanisms associated with impairments in both cognitive control for confusable distractors and the ability to control emotional distraction.
•Reduced volume of inferior frontal gyrus (IFG) in patients with PTSD.•This abnormality correlated with CAPS scores, symptoms of PTSD.•IFG was also less activated during WM maintenance with face distractors.•Increased activity in STG during trauma-related distractor trial was observed.•These findings may represent dissociation between cognition and emotion regulation in PTSD.
Nanostructured bismuth (Bi) nanoflakes were designed and directly grown on Cu substrate using a novel pulse electrodeposition method. Compared with conventional bismuth film grown by direct current ...electrodeposition, Bi nanoflakes have large number of edge and corner sites. As it has been proven by numerical simulation, sharp edge or corner sites of the nanostructures form strong local electric fields, which boost the catalytic activity for the electrochemical reduction of CO2 in aqueous solution. The Bi nanoflakes showed a high HCOO- faradaic efficiency (FE = 79.5%) at low potential of −0.4 VRHE and achieved a maximum FE close to 100% at −0.6 VRHE, meaning that the shape control of Bi electrocatalyst is indeed an efficient way to reduce the electrical power consumption for HCOO- production. Moreover, Bi nanoflakes were stable during 10h operation in 0.1M KHCO3 aqueous solution. The results suggest that tailoring the nanostructure is a key in developing a high performance noble-metal-free electrocatalyst for electrochemical CO2 reduction in aqueous solution.
Bismuth (Bi) nanoflakes were designed using a novel pulse electrodeposition method. Compared with conventional Bi film grown by direct electrodeposition, Bi nanoflakes have a large number of edge and corner sites, which boost the catalytic activity. The novel-metal-free Bi electrocatalyst achieved highly electrochemical CO2 reduction in aqueous solution. Display omitted
•Bismuth (Bi) nanoflakes were designed and directly grown on Cu substrate using a novel pulse-electrodeposition method.•Relationship between the shape and catalytic performance was elucidated.•Electrochemical CO2 reduction with high HCOO- production rate was achieved at low potential.
The clinical utility of a small-caliber vascular graft is still limited, owing to the occlusion of graft by thrombosis and restenosis. A small-caliber vascular graft (diameter, 2.5 mm) fabricated by ...electrospinning with a polyurethane (PU) elastomer (Pellethane) and biofunctionalized with heparin and two cell-adhesive peptides, GRGDS and YIGSR, was developed for the purpose of preventing the thrombosis and restenosis through antithrombogenic activities and endothelialization. The vascular grafts showed slightly reduced adhesion of platelets and significantly decreased adsorption of fibrinogen. In vitro studies demonstrated that peptide treatment on a vascular graft enhanced the attachment of human umbilical vein endothelial cells (HUVECs), and the presence of heparin and peptides on the graft significantly increased the proliferation of HUVECs. In vivo implantation of heparin/peptides coimmobilized graft (PU–PEG–Hep/G+Y) and PU (control) grafts was performed using an abdominal aorta rabbit model for 60 days followed by angiographic monitoring and explanting for histological analyses. The patency was significantly higher for the modified PU grafts (71.4%) compared to the PU grafts (46.2%) at 9 weeks after implantation. The nontreated PU grafts showed higher levels of α-SMA expression compared to the modified grafts, and for both samples, the proximal and distal regions expressed higher levels compared to the middle region of the grafts. Moreover, immobilization of heparin and peptides and adequate porous structure were found to play important roles in endothelialization and cellular infiltration. Our results strongly encourage that the development of small-caliber vascular grafts is feasible.
DCE-MRI provides information about vascular permeability and tissue perfusion through the acquisition of pharmacokinetic parameters. However, traditional methods for estimating these pharmacokinetic ...parameters involve fitting tracer kinetic models, which often suffer from computational complexity and low accuracy due to noisy arterial input function (AIF) measurements. Although some deep learning approaches have been proposed to tackle these challenges, most existing methods rely on supervised learning that requires paired input DCE-MRI and labeled pharmacokinetic parameter maps. This dependency on labeled data introduces significant time and resource constraints and potential noise in the labels, making supervised learning methods often impractical. To address these limitations, we present a novel unpaired deep learning method for estimating pharmacokinetic parameters and the AIF using a physics-driven CycleGAN approach. Our proposed CycleGAN framework is designed based on the underlying physics model, resulting in a simpler architecture with a single generator and discriminator pair. Crucially, our experimental results indicate that our method does not necessitate separate AIF measurements and produces more reliable pharmacokinetic parameters than other techniques.
Display omitted
•Unpaired deep learning for estimating PK parameters using a physics-driven CyeleGAN.•The proposed CycleGAN framework is designed based on the physics model.•Our method does not necessitate AIF measurements and produces reliable PK parameters.
Human mesenchymal stem cells (hMSCs) have great potential as cell sources for bone tissue engineering and regeneration, but the control and induction of their specific differentiation into bone cells ...remain challenging. Graphene-based nanomaterials are considered attractive candidates for biomedical applications such as scaffolds in tissue engineering, substrates for SC differentiation and components of implantable devices, due to their biocompatible and bioactive properties. Despite the potential biomedical applications of graphene and its derivatives, only limited information is available regarding their osteogenic activity. This study concentrates upon the effects of reduced graphene oxide (rGO)-coated hydroxyapatite (HAp) composites on osteogenic differentiation of hMSCs. The average particle sizes of HAp and rGO were 1270 ± 476 nm and 438 ± 180 nm, respectively. When coated on HAp particulates, rGO synergistically enhanced spontaneous osteogenic differentiation of hMSCs, without hampering their proliferation. This result was confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. It is suggested that rGO-coated HAp composites can be effectively utilized as dental and orthopedic bone fillers since these graphene-based particulate materials have potent effects on stimulating the spontaneous differentiation of MSCs and show superior bioactivity and osteoinductive potential.
Dipeptidyl peptidase-4 (DPP-4) inhibitors are glucose-lowering drugs for type 2 diabetes mellitus (T2DM). We investigated whether evogliptin® (EVO), a DPP-4 inhibitor, could protect against diabetic ...cardiomyopathy (DCM) and the underlying mechanisms. Eight-week-old diabetic and obese db/db mice were administered EVO (100 mg/kg/day) daily by oral gavage for 12 weeks. db/db control mice and C57BLKS/J as wild-type (WT) mice received equal amounts of the vehicle. In addition to the hypoglycemic effect, we examined the improvement in cardiac contraction/relaxation ability, cardiac fibrosis, and myocardial hypertrophy by EVO treatment. To identify the mechanisms underlying the improvement in diabetic cardiomyopathy by EVO treatment, its effect on lipotoxicity and the mitochondrial damage caused by lipid droplet accumulation in the myocardium were analyzed. EVO lowered the blood glucose and HbA1c levels and improved insulin sensitivity but did not affect the body weight or blood lipid profile. Cardiac systolic/diastolic function, hypertrophy, and fibrosis were improved in the EVO-treated group. EVO prevented cardiac lipotoxicity by reducing the accumulation of lipid droplets in the myocardium through suppression of CD36, ACSL1, FABP3, PPARgamma, and DGAT1 and enhancement of the phosphorylation of FOXO1, indicating its inhibition. The EVO-mediated improvement in mitochondrial function and reduction in damage were achieved through activation of PGC1a/NRF1/TFAM, which activates mitochondrial biogenesis. RNA-seq results for the whole heart confirmed that EVO treatment mainly affected the differentially expressed genes (DEGs) related to lipid metabolism. Collectively, these findings demonstrate that EVO improves cardiac function by reducing lipotoxicity and mitochondrial injury and provides a potential therapeutic option for DCM.
Neural cell adhesion and neurite outgrowth were examined on graphene-based biomimetic substrates. The biocompatibility of carbon nanomaterials such as graphene and carbon nanotubes (CNTs), that is, ...single-walled and multiwalled CNTs, against pheochromocytoma-derived PC-12 neural cells was also evaluated by quantifying metabolic activity (with WST-8 assay), intracellular oxidative stress (with ROS assay), and membrane integrity (with LDH assay). Graphene films were grown by using chemical vapor deposition and were then coated onto glass coverslips by using the scooping method. Graphene sheets were patterned on SiO2/Si substrates by using photolithography and were then covered with serum for a neural cell culture. Both types of CNTs induced significant dose-dependent decreases in the viability of PC-12 cells, whereas graphene exerted adverse effects on the neural cells just at over 62.5 ppm. This result implies that graphene and CNTs, even though they were the same carbon-based nanomaterials, show differential influences on neural cells. Furthermore, graphene-coated or graphene-patterned substrates were shown to substantially enhance the adhesion and neurite outgrowth of PC-12 cells. These results suggest that graphene-based substrates as biomimetic cues have good biocompatibility as well as a unique surface property that can enhance the neural cells, which would open up enormous opportunities in neural regeneration and nanomedicine.
Objectives
The objective of this cross‐sectional study was to investigate the relationship between depression in elderly individuals and chronic illness, subjective health status, and cognitive ...impairment.
Method
This study used the dataset of the Survey of Living Conditions and Welfare Needs of Korean Older Persons, which was conducted by the Korea Institute for Health and Social Affairs in 2011. Participants (n = 10 674) were randomly selected from a pool of individuals aged 65 years and older. Elderly depression was evaluated by the short version of the Geriatric Depression Scale. Multivariate logistic regression was used to investigate factors associated with depression in terms of their sociodemographic and health‐related characteristics.
Results
Our results revealed that chronic illness, subjective health status, and cognitive impairment were significant factors associated with depression. In particular, subjective health status showed the highest odds ratio (OR) (OR for bad subjective health status = 4.290, P < 0.001), followed by chronic illness (OR for three or more chronic illnesses = 1.403, P < 0.01) and cognitive impairment (OR = 1.347, P < 0.001) in the final model. Interestingly, the significant association between chronic illness and depression was attenuated (OR for three or more chronic illnesses = 1.403, P = 0.01) or even disappeared (OR for two chronic illnesses = 1.138, P = 0.274; OR for one chronic illnesses = 0.999, P = 0.996) after adjustment for subjective health status in the final model; this may be attributable to the close relationship among the variables studied: chronic illness, subjective health status, and depression.
Conclusions
Development and implementation of prevention strategies, including management of chronic illness, individual's perception of health status, and cognitive impairment, could possibly reduce the impact of depression.
We discuss nonstandard interpretations of the 750 GeV diphoton excess recently reported by the ATLAS and CMS Collaborations which do not involve a new, relatively broad resonance with a mass near ...750 GeV. Instead, we consider the sequential cascade decay of a much heavier, possibly quite narrow, resonance into two photons along with one or more additional particles. The resulting diphoton invariant mass signal is generically rather broad, as suggested by the data. We examine three specific event topologies-the "antler," the "sandwich," and the two-step cascade decay-and show that they all can provide a good fit to the observed published data. In each case, we delineate the preferred mass parameter space selected by the best fit. In spite of the presence of extra particles in the final state, the measured diphoton p_{T} spectrum is moderate due to its anticorrelation with the diphoton invariant mass. We comment on the future prospects of discriminating with higher statistics between our scenarios, as well as from more conventional interpretations.
PDF
