130 research outputs found
Power Control for Full-Duplex Relay-Enhanced Cellular Networks With QoS Guarantees
Full-duplex (FD) has emerged as a new communication paradigm with the potential advantage of enhancing the capacity of the wireless communication systems. In this paper, we consider an FD relay-enhanced cellular network, wherein the residual self-interference, the uplink-downlink interference, as well as the relay-access-link interference are the vital restrictions to network performance. To this end, we investigate power control design for the FD relay-enhanced cellular networks, so as to maximize the system spectral efficiency while fulfilling the quality of service (QoS) requirements of both the uplink and downlink user equipments (UEs). We characterize the properties of the optimal transmit power allocation, and propose a power control algorithm based on signomial programming to coordinate the transmit power of the uplink UE, base station, and relay stations to mitigate the interference. Meanwhile, we also derive the closed-form optimal transmit power allocation for the conventional half-duplex (HD) transmission mode. Moreover, we conduct extensive simulation experiments to study the network-level gain of the FD mode over the HD mode in the relay-enhanced cellular networks. Simulation results demonstrate that FD relaying outperforms HD relaying on improving the spectral and energy efficiency, as well as provisioning QoS guarantees for both the uplink and downlink users
Power Control for Full-Duplex Relay-Enhanced Cellular Networks With QoS Guarantees
Full-duplex (FD) has emerged as a new communication paradigm with the potential advantage of enhancing the capacity of the wireless communication systems. In this paper, we consider an FD relay-enhanced cellular network, wherein the residual self-interference, the uplink-downlink interference, as well as the relay-access-link interference are the vital restrictions to network performance. To this end, we investigate power control design for the FD relay-enhanced cellular networks, so as to maximize the system spectral efficiency while fulfilling the quality of service (QoS) requirements of both the uplink and downlink user equipments (UEs). We characterize the properties of the optimal transmit power allocation, and propose a power control algorithm based on signomial programming to coordinate the transmit power of the uplink UE, base station, and relay stations to mitigate the interference. Meanwhile, we also derive the closed-form optimal transmit power allocation for the conventional half-duplex (HD) transmission mode. Moreover, we conduct extensive simulation experiments to study the network-level gain of the FD mode over the HD mode in the relay-enhanced cellular networks. Simulation results demonstrate that FD relaying outperforms HD relaying on improving the spectral and energy efficiency, as well as provisioning QoS guarantees for both the uplink and downlink users
Inferring gene expression dynamics via functional regression analysis
<p>Abstract</p> <p>Background</p> <p>Temporal gene expression profiles characterize the time-dynamics of expression of specific genes and are increasingly collected in current gene expression experiments. In the analysis of experiments where gene expression is obtained over the life cycle, it is of interest to relate temporal patterns of gene expression associated with different developmental stages to each other to study patterns of long-term developmental gene regulation. We use tools from functional data analysis to study dynamic changes by relating temporal gene expression profiles of different developmental stages to each other.</p> <p>Results</p> <p>We demonstrate that functional regression methodology can pinpoint relationships that exist between temporary gene expression profiles for different life cycle phases and incorporates dimension reduction as needed for these high-dimensional data. By applying these tools, gene expression profiles for pupa and adult phases are found to be strongly related to the profiles of the same genes obtained during the embryo phase. Moreover, one can distinguish between gene groups that exhibit relationships with positive and others with negative associations between later life and embryonal expression profiles. Specifically, we find a positive relationship in expression for muscle development related genes, and a negative relationship for strictly maternal genes for <it>Drosophila</it>, using temporal gene expression profiles.</p> <p>Conclusion</p> <p>Our findings point to specific reactivation patterns of gene expression during the <it>Drosophila </it>life cycle which differ in characteristic ways between various gene groups. Functional regression emerges as a useful tool for relating gene expression patterns from different developmental stages, and avoids the problems with large numbers of parameters and multiple testing that affect alternative approaches.</p
Dynamics of dendritic cell maturation are identified through a novel filtering strategy applied to biological time-course microarray replicates
<p>Abstract</p> <p>Background</p> <p>Dendritic cells (DC) play a central role in primary immune responses and become potent stimulators of the adaptive immune response after undergoing the critical process of maturation. Understanding the dynamics of DC maturation would provide key insights into this important process. Time course microarray experiments can provide unique insights into DC maturation dynamics. Replicate experiments are necessary to address the issues of experimental and biological variability. Statistical methods and averaging are often used to identify significant signals. Here a novel strategy for filtering of replicate time course microarray data, which identifies consistent signals between the replicates, is presented and applied to a DC time course microarray experiment.</p> <p>Results</p> <p>The temporal dynamics of DC maturation were studied by stimulating DC with poly(I:C) and following gene expression at 5 time points from 1 to 24 hours. The novel filtering strategy uses standard statistical and fold change techniques, along with the consistency of replicate temporal profiles, to identify those differentially expressed genes that were consistent in two biological replicate experiments. To address the issue of cluster reproducibility a consensus clustering method, which identifies clusters of genes whose expression varies consistently between replicates, was also developed and applied. Analysis of the resulting clusters revealed many known and novel characteristics of DC maturation, such as the up-regulation of specific immune response pathways. Intriguingly, more genes were down-regulated than up-regulated. Results identify a more comprehensive program of down-regulation, including many genes involved in protein synthesis, metabolism, and housekeeping needed for maintenance of cellular integrity and metabolism.</p> <p>Conclusions</p> <p>The new filtering strategy emphasizes the importance of consistent and reproducible results when analyzing microarray data and utilizes consistency between replicate experiments as a criterion in both feature selection and clustering, without averaging or otherwise combining replicate data. Observation of a significant down-regulation program during DC maturation indicates that DC are preparing for cell death and provides a path to better understand the process. This new filtering strategy can be adapted for use in analyzing other large-scale time course data sets with replicates.</p
Social Isolation and Incident Heart Failure Hospitalization in Older Women: Women\u27s Health Initiative Study Findings
Background
The association of social isolation or lack of social network ties in older adults is unknown. This knowledge gap is important since the risk of heart failure (HF) and social isolation increase with age. The study examines whether social isolation is associated with incident HF in older women, and examines depressive symptoms as a potential mediator and age and race and ethnicity as effect modifiers.
Methods and Results
This study included 44 174 postmenopausal women of diverse race and ethnicity from the WHI (Women\u27s Health Initiative) study who underwent annual assessment for HF adjudication from baseline enrollment (1993-1998) through 2018. We conducted a mediation analysis to examine depressive symptoms as a potential mediator and further examined effect modification by age and race and ethnicity. Incident HF requiring hospitalization was the main outcome. Social isolation was a composite variable based on marital/partner status, religious ties, and community ties. Depressive symptoms were assessed using CES-D (Center for Epidemiology Studies-Depression). Over a median follow-up of 15.0 years, we analyzed data from 36 457 women, and 2364 (6.5%) incident HF cases occurred; 2510 (6.9%) participants were socially isolated. In multivariable analyses adjusted for sociodemographic, behavioral, clinical, and general health/functioning; socially isolated women had a higher risk of incident HF than nonisolated women (HR, 1.23; 95% CI, 1.08-1.41). Adding depressive symptoms in the model did not change this association (HR, 1.22; 95% CI, 1.07-1.40). Neither race and ethnicity nor age moderated the association between social isolation and incident HF.
Conclusions
Socially isolated older women are at increased risk for developing HF, independent of traditional HF risk factors.
Registration
URL: http://www.clinicaltrials.gov; Unique identifier: NCT00000611
Comparative pharmacokinetics of polymyxin B in critically ill elderly patients with extensively drug-resistant gram-negative bacteria infections
Introduction: Elderly patients are more prone to develop acute kidney injury during infections and polymyxin B (PMB)-associated nephrotoxicity than young patients. The differential response to PMB between the elderly and young critically ill patients is unknown. We aimed to assess PMB exposure in elderly patients compared with young critically ill patients, and to determine the covariates of PMB pharmacokinetics in critically ill patients.Methods: Seventeen elderly patients (age ≥ 65 years) and six young critically ill patients (age < 65 years) were enrolled. Six to eight blood samples were collected during the 12 h intervals after at least six doses of intravenous PMB in each patient. PMB plasma concentrations were quantified by high-performance liquid chromatography-tandem mass spectrometry. The primary outcome was PMB exposure as assessed by the area under the concentration-time curve over 24 h at steady state (AUCss, 0–24 h).Results and Discussion: The elderly group had lower total body weight (TBW) and higher Charlson comorbidity scores than young group. Neither AUCss, 0–24 h nor normalized AUCss, 0–24 h (adjusting AUC for the daily dose in mg/kg of TBW) was significantly different between the elderly group and young group. The half-life time was longer in the elderly patients than in young patients (11.21 vs 6.56 h respectively, p = 0.003). Age and TBW were the covariates of half-life time (r = 0.415, p = 0.049 and r = −0.489, p = 0.018, respectively). TBW was the covariate of clearance (r = 0.527, p = 0.010) and AUCss, 0–24 h (r = −0.414, p = 0.049). Patients with AUCss, 0–24 h ≥ 100 mg·h/L had higher baseline serum creatinine levels and lower TBW than patients with AUCss, 0–24 h < 50 mg·h/L or patients with AUCss, 0–24 h 50–100 mg·h/L. The PMB exposures were comparable in elderly and young critically ill patients. High baseline serum creatinine levels and low TBW was associated with PMB overdose.Trial registration: ChiCTR2300073896 retrospectively registered on 25 July 2023
Social isolation and incident heart failure hospitalization in older women: Women\u27s health initiative study findings
Background The association of social isolation or lack of social network ties in older adults is unknown. This knowledge gap is important since the risk of heart failure (HF) and social isolation increase with age. The study examines whether social isolation is associated with incident HF in older women, and examines depressive symptoms as a potential mediator and age and race and ethnicity as effect modifiers. Methods and Results This study included 44 174 postmenopausal women of diverse race and ethnicity from the WHI (Women\u27s Health Initiative) study who underwent annual assessment for HF adjudication from baseline enrollment (1993-1998) through 2018. We conducted a mediation analysis to examine depressive symptoms as a potential mediator and further examined effect modification by age and race and ethnicity. Incident HF requiring hospitalization was the main outcome. Social isolation was a composite variable based on marital/partner status, religious ties, and community ties. Depressive symptoms were assessed using CES-D (Center for Epidemiology Studies-Depression). Over a median follow-up of 15.0 years, we analyzed data from 36 457 women, and 2364 (6.5%) incident HF cases occurred; 2510 (6.9%) participants were socially isolated. In multivariable analyses adjusted for sociodemographic, behavioral, clinical, and general health/functioning; socially isolated women had a higher risk of incident HF than nonisolated women (HR, 1.23; 95% CI, 1.08-1.41). Adding depressive symptoms in the model did not change this association (HR, 1.22; 95% CI, 1.07-1.40). Neither race and ethnicity nor age moderated the association between social isolation and incident HF. Conclusions Socially isolated older women are at increased risk for developing HF, independent of traditional HF risk factors. Registration URL: http://www.clinicaltrials.gov; Unique identifier: NCT00000611
Plasmin Plays an Essential Role in Amplification of Psoriasiform Skin Inflammation in Mice
BACKGROUND: Although increased levels of plasminogen activators have been found in psoriatic lesions, the role of plasmin converted from plasminogen by plasminogen activators in pathogenesis of psoriasis has not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: Here we examined the contribution of plasmin to amplification of inflammation in patients with psoriasis. We found that plasminogen was diminished, but that the amount and activity of its converted product plasmin were markedly increased in psoriasis. Moreover, annexin II, a receptor for plasmin was dramatically increased in both dermis and epidermis in psoriasis. Plasmin at sites of inflammation was pro-inflammatory, eliciting production of inflammatory factors, including CC chemokine ligand 20 (CCL20) and interleukin-23 (IL-23), that was mediated by the nuclear factor-kappaB (NF-κB) signaling pathway and that had an essential role in the recruitment and activation of pathogenic C-C chemokine receptor type 6 (CCR6)+ T cells. Moreover, intradermal injection of plasmin or plasmin together with recombinant monocyte/macrophage chemotactic protein-1 (MCP-1) resulted in induction of psoriasiform skin inflammation around the injection sites with several aspects of human psoriasis in mice. CONCLUSIONS/SIGNIFICANCE: Plasmin converted from plasminogen by plasminogen activators plays an essential role in amplification of psoriasiform skin inflammation in mice, and targeting plasmin receptor--annexin II--may harbor therapeutic potential for the treatment of human psoriasis
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