220 research outputs found

    A Comprehensive Analysis of 5G Heterogeneous Cellular Systems operating over κ\kappa-μ\mu Shadowed Fading Channels

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    Emerging cellular technologies such as those proposed for use in 5G communications will accommodate a wide range of usage scenarios with diverse link requirements. This will include the necessity to operate over a versatile set of wireless channels ranging from indoor to outdoor, from line-of-sight (LOS) to non-LOS, and from circularly symmetric scattering to environments which promote the clustering of scattered multipath waves. Unfortunately, many of the conventional fading models adopted in the literature to develop network models lack the flexibility to account for such disparate signal propagation mechanisms. To bridge the gap between theory and practical channels, we consider κ\kappa-μ\mu shadowed fading, which contains as special cases, the majority of the linear fading models proposed in the open literature, including Rayleigh, Rician, Nakagami-m, Nakagami-q, One-sided Gaussian, κ\kappa-μ\mu, η\eta-μ\mu, and Rician shadowed to name but a few. In particular, we apply an orthogonal expansion to represent the κ\kappa-μ\mu shadowed fading distribution as a simplified series expression. Then using the series expressions with stochastic geometry, we propose an analytic framework to evaluate the average of an arbitrary function of the SINR over κ\kappa-μ\mu shadowed fading channels. Using the proposed method, we evaluate the spectral efficiency, moments of the SINR, bit error probability and outage probability of a KK-tier HetNet with KK classes of BSs, differing in terms of the transmit power, BS density, shadowing characteristics and small-scale fading. Building upon these results, we provide important new insights into the network performance of these emerging wireless applications while considering a diverse range of fading conditions and link qualities

    Early prediction of molecular remission by monitoring BCR-ABL transcript levels in patients achieving a complete cytogenetic response after imatinib therapy for posttransplantation chronic myelogenous leukemia relapse

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    Imatinib induces a high complete cytogenetic response (CCR) rate in relapsed chronic myelogenous leukemia. By analyzing minimal residual disease (MRD) under the levels of CCR, we tried to assess the molecular response after imatinib therapy. By using real-time quantitative reverse transcriptase-polymerase chain reaction (Q-RT-PCR), MRD was evaluated in 23 patients (3 in cytogenetic relapse, 6 in chronic phase, 9 in accelerated phase, and 5 in blast crisis) who were treated with standard-dose imatinib for relapsed chronic myelogenous leukemia after allogeneic stem cell transplantation. With a median therapy time of 399 days (range, 35–817 days), 19 (83%) patients achieved a CCR. Meanwhile, 11 (58%) of them achieved a molecular remission (MR), which was associated with improved survival. The Q-RT-PCR data were compared according to the best response (MR, n = 11; CCR, n = 8) in the patients achieving a CCR. The BCR-ABL/ABL ratios were similar in 2 groups at 3 months but were significantly different at 6 months (median, 0.0000012 for MR and 0.00022 for CCR; P = .003). The probability of a subsequent MR was significantly higher in patients with a lower BCR-ABL/ABL ratio at 6 months (100% for <0.0001 versus 33% for ≥0.0001; P = .006) or a greater reduction in the level between 3 and 6 months (log-reduction ≥1.0;, 100%; <1.0, 17%; P = .003). Q-RT-PCR is a reliable method for monitoring MRD: the early trends in the BCR-ABL/ABL ratio may be clinically useful in discriminating patients who will achieve an MR from those who will remain in CCR

    Titanium dioxide induces apoptotic cell death through reactive oxygen species-mediated Fas upregulation and Bax activation

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    Background: Titanium dioxide (TiO2) has been widely used in many areas, including biomedicine, cosmetics, and environmental engineering. Recently, it has become evident that some TiO2 particles have a considerable cytotoxic effect in normal human cells. However, the molecular basis for the cytotoxicity of TiO2 has yet to be defined.Methods and results: In this study, we demonstrated that combined treatment with TiO2 nanoparticles sized less than 100 nm and ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-dependent upregulation of Fas and conformational activation of Bax in normal human cells. Treatment with P25 TiO2 nanoparticles with a hydrodynamic size distribution centered around 70 nm (TiO2P25-70) together with ultraviolet A irradiation-induced caspase-dependent apoptotic cell death, accompanied by transcriptional upregulation of the death receptor, Fas, and conformational activation of Bax. In line with these results, knockdown of either Fas or Bax with specific siRNA significantly inhibited TiO2-induced apoptotic cell death. Moreover, inhibition of reactive oxygen species with an antioxidant, N-acetyl-L-cysteine, clearly suppressed upregulation of Fas, conformational activation of Bax, and subsequent apoptotic cell death in response to combination treatment using TiO2P25-70 and ultraviolet A irradiation.Conclusion: These results indicate that sub-100 nm sized TiO2 treatment under ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-mediated upregulation of the death receptor, Fas, and activation of the preapoptotic protein, Bax. Elucidating the molecular mechanisms by which nanosized particles induce activation of cell death signaling pathways would be critical for the development of prevention strategies to minimize the cytotoxicity of nanomaterials.This work was supported by the Korea Ministry of Environment and The Eco-Technopia 21 Project (091-091-081)

    The expression of growth factor signaling genes in co-culture IVM

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    The objective of this study was to determine the expression of growth factor signaling genes in human adiposederived stem cells (ASCs), porcine oocytes, and cumulus during in vitro maturation (IVM). The human ASCs (from 2 young and 2 old donors) were used for the co-culture IVM system. The maturation rate was examined based on polar body extrusion. The expression of the growth factor signaling genes from ASCs, oocytes, and cumulus were measured using qPCR. All data were analyzed using ANOVA followed by Tukey’s test. The expression of the h-IGF1 signaling genes from human ASCs cells showed similar values in all groups and the h-FGF2 expressions were higher in the young donors than the old ones. The p-FGF2, p-FGFR2, and p-TGFβ1 expressions in the oocytes as well as p-IGFR in the cumulus that were co-cultured from the young donors showed higher values than the old and control groups. The apoptotic ratio (p-BAX/p-BCL2) from the oocytes and cumulus in both co-culture groups also showed lower levels than the control (P<0.05). Oocyte maturation rates were significantly increased in all co-cultured groups (Y1 (85.9 ± 2.2%), Y2 (91.2 ± 1.1%), O1 (86.3 ± 1.5%), and O2 (86.5 ± 2.3%)) compared with the control (76.7 ± 1.1%; P<0.05). Although the expression of growth factor signaling genes was varied, young donors’ ASCs might support in vitro maturation beħer than those from old donors

    Lower leg compartment syndrome following prolonged orthopedic surgery in the lithotomy position -A case report-

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    Surgical procedures necessitating the prolonged use of the lithotomy position can be associated with neuromuscular dysfunction. Compartment syndrome of the lower leg is a grave complication which, if unrecognized, can lead to either permanent neuromuscular dysfunction or limb loss. We report a case of compartment syndrome of lower leg that occurred in male patient aged 20 years after 380 minutes arthroscopic surgery in the lithotomy position

    The Clinicopathological Significance of Tissue Levels of Hypoxia-Inducible Factor-1α and Vascular Endothelial Growth Factor in Gastric Cancer

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