Orthogonal frequency division multiplexing (OFDM) technique has been widely adopted in wireless systems, but it is known for being sensitive to synchronization errors. In this paper, we present ...timing and frequency synchronization algorithms for OFDM downlink transmissions using Zadoff-Chu sequences. We show that the current timing synchronization method employing Zadoff-Chu sequences is sensitive to carrier frequency offsets. To reduce this sensitivity, we develop conditions for the selection of appropriate Zadoff-Chu sequences. We then design a training sequence and propose joint signal detection, timing, and carrier frequency offset estimation algorithms for OFDM downlink transmissions. We show that the proposed schemes simplify the overall synchronization architecture and improve the performance compared to the existing schemes in the literature.
Self-assembling peptides are biomedical materials with unique structures that are formed in response to various environmental conditions. Governed by their physicochemical characteristics, the ...peptides can form a variety of structures with greater reactivity than conventional non-biological materials. The structural divergence of self-assembling peptides allows for various functional possibilities; when assembled, they can be used as scaffolds for cell and tissue regeneration, and vehicles for drug delivery, conferring controlled release, stability, and targeting, and avoiding side effects of drugs. These peptides can also be used as drugs themselves. In this review, we describe the basic structure and characteristics of self-assembling peptides and the various factors that affect the formation of peptide-based structures. We also summarize the applications of self-assembling peptides in the treatment of various diseases, including cancer. Furthermore, the in-cell self-assembly of peptides, termed reverse self-assembly, is discussed as a novel paradigm for self-assembling peptide-based nanovehicles and nanomedicines.
This paper investigates the performance of two-tier femtocell networks with cochannel femtocell deployment while considering cellular geometry and cross-tier interference in downlink. We derive the ...per-tier outage probability by introducing a simplified mathematical model that provides closely approximate femtocell interference distribution. Based on the outage probability analysis, we also derive the transmission capacity that represents the total capacity of the cochannel two-tier networks with outage constraints. The performance analysis provides an accurate characterization of the outage probability and the transmission capacity, accounting for the density of randomly scattered femtocells and femtocell transmission power.
The amplify-and-forward (AF) relaying system considered here consists of a source node with M transmit antennas, and relay and destination nodes with a single antenna each. The closed-form ...expressions for the outage probabilities for maximum-ratio-transmission (MRT) at the source are presented for some specific values of M. Numerical results show that increasing M from 1 to 2 can achieve roughly a 3 dB SNR gain, guaranteeing the same outage probability. However, we discover that for M ges 3, the additional gain compared to M = 2 decreases quickly as the SNR increases. Therefore, increasing M above 3 does not achieve significantly greater gain over M = 2 at high SNR.
Prion diseases are neurodegenerative disorders in humans and animals for which no therapies are currently available. Here, we report that
Valeton (Zingiberaceae) (
) extract was partly effective in ...decreasing prion aggregation and propagation in both in vitro and in vivo models.
extract inhibited self-aggregation of recombinant prion protein (PrP) in a test tube assay and decreased the accumulation of scrapie PrP (PrP
) in ScN2a cells, a cultured neuroblastoma cell line with chronic prion infection, in a concentration-dependent manner.
extract also modified the course of the disease in mice inoculated with mouse-adapted scrapie prions, completely preventing the onset of prion disease in three of eight mice. Biochemical and neuropathological analyses revealed a statistically significant reduction in PrP
accumulation, spongiosis, astrogliosis, and microglia activation in the brains of mice that avoided disease onset. Furthermore, PrP
accumulation in the spleen of mice was also reduced.
extract precluded prion infection in cultured cells as demonstrated by the modified standard scrapie cell assay. This study suggests that
extract could contribute to investigating the modulation of prion propagation.
Diabetic retinopathy is predominantly caused by vascular endothelial growth factor (VEGF)-induced vascular leakage; however, the underlying mechanism is unclear. Here we designed an in vivo ...transglutaminase (TGase) activity assay in mouse retina and demonstrated that hyperglycemia induced vascular leakage by activating TGase2 in diabetic retina. VEGF elevated TGase2 activity through sequential elevation of intracellular Ca(2+) and reactive oxygen species (ROS) concentrations in endothelial cells. The TGase inhibitors cystamine and monodansylcadaverin or TGase2 small interfering RNA (siRNA) prevented VEGF-induced stress fiber formation and vascular endothelial (VE)-cadherin disruption, which play a critical role in modulating endothelial permeability. Intravitreal injection of two TGase inhibitors or TGase2 siRNA successfully inhibited hyperglycemia-induced TGase activation and microvascular leakage in the retinas of diabetic mice. C-peptide or ROS scavengers also inhibited TGase activation in diabetic mouse retinas. The role of TGase2 in VEGF-induced vascular leakage was further supported using diabetic TGase2(-/-) mice. Thus, our findings suggest that ROS-mediated activation of TGase2 plays a key role in VEGF-induced vascular leakage by stimulating stress fiber formation and VE-cadherin disruption.
The use of non-chemical methods to differentiate stem cells has attracted researchers from multiple disciplines, including the engineering and the biomedical fields. No doubt, growth factor based ...methods are still the most dominant of achieving some level of proliferation and differentiation control--however, chemical based methods are still limited by the quality, source, and amount of the utilized reagents. Well-defined non-chemical methods to differentiate stem cells allow stem cell scientists to control stem cell biology by precisely administering the pre-defined parameters, whether they are structural cues, substrate stiffness, or in the form of current flow. We have developed a culture system that allows normal stem cell growth and the option of applying continuous and defined levels of electric current to alter the cell biology of growing cells. This biphasic current stimulator chip employing ITO electrodes generates both positive and negative currents in the same culture chamber without affecting surface chemistry. We found that biphasic electrical currents (BECs) significantly increased the proliferation of fetal neural stem cells (NSCs). Furthermore, BECs also promoted the differentiation of fetal NSCs into neuronal cells, as assessed using immunocytochemistry. Our results clearly show that BECs promote both the proliferation and neuronal differentiation of fetal NSCs. It may apply to the development of strategies that employ NSCs in the treatment of various neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases.
The number of coefficients for estimating time-varying channel is generally much larger than the maximum number of observable data. Linearly time-varying channel (LTV) models have been widely used as ...a way of reducing the number of these channel parameters. This approach allows estimation using the channel slope and channel frequency response between symbols. A fatal problem with this approach, however, is that before it is even initiated, the estimated channel in the frequency domain has already been degraded by inter-carrier interference (ICI). We demonstrate this by analyzing the channel estimation mean square error (MSE) and signal to interference and noise ratio (SINR) after ICI cancellation with respect to the LTV model. We then propose a new channel estimation technique using dual-ICI cancellation which resolves this problem by pre-canceling ICI for the channel estimation using the channel of the previous symbol and post-canceling ICI for symbol detection with the more accurate channel information. The process is initialized using the first symbol as a preamble to estimate the channel in the time domain. Performance comparisons of MSE and SINR show that the proposed method is better suited to fast-fading channels than the conventional method, where ICI dominates the interference and noise power.
Effective collaboration and communication among health care team members are critical for providing safe medical care. Interprofessional education aims to instruct healthcare students how to learn ...with, from, and about healthcare professionals from different occupations to encourage effective collaboration to provide safe and high-quality patient care. The purpose of this study is to confirm the effectiveness of Interprofessional education by comparing students' attitudes toward interprofessional learning before and after simulation-based interprofessional education, the perception of teamwork and collaboration between physicians and nurses, and the self-reported competency differences among students in interprofessional practice.
The survey responses from 37 5th-year medical students and 38 4th-year nursing students who participated in an interprofessional education program were analyzed. The Attitude Towards Teamwork in Training Undergoing Designed Educational Simulation scale, the Jefferson Scale of Attitudes Toward Physician-Nurse Collaboration, and the Interprofessional Education Collaborative competency scale were used for this study. The demographic distribution of the study participants was obtained, and the perception differences before and after participation in interprofessional education between medical and nursing students were analyzed.
After interprofessional education, student awareness of interprofessional learning and self-competency in interprofessional practice improved. Total scores for the Jefferson Scale of Attitudes Toward Physician-Nurse Collaboration did not change significantly among medical students but increased significantly among nursing students. Additionally, there was no significant change in the perception of the role of other professions among either medical or nursing students.
We observed an effect of interprofessional education on cultivating self-confidence and recognizing the importance of interprofessional collaboration between medical professions. It can be inferred that exposure to collaboration situations through Interprofessional education leads to a positive perception of interprofessional learning. However, even after their interprofessional education experience, existing perceptions of the role of other professional groups in the collaboration situation did not change, which shows the limitations of a one-time short-term program. This suggests that efforts should be made to ensure continuous exposure to social interaction experiences with other professions.
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