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This study presents a computationally efficient algorithm for joint carrier frequency offset (CFO) and channel estimation for generalized frequency division multiplexing (GFDM) systems. The proposed algorithm employs a Zadoff-Chu ( ZC ) sequence as a training sequence spreading in the frequency domain for all subsymbols of the GFDM pilot symbol. The proposed algorithm first estimates the phase rotation factor in the pilot symbol and then coherently combines all subsymbols according to this estimate. The CFO is then estimated from the root of the cost function constructed using the ZC sequence. Finally, the channel estimate is obtained through maximum likelihood estimation and the use of CFO-compensated signals. Compared with conventional approaches, in addition to demonstrating improved estimation accuracy, the proposed algorithm is more computationally efficient because of the use of the ZC sequence. Computer simulations confirm the feasibility of the proposed algorithm.

This study presents a novel frequency synchronization scheme for orthogonal frequency division multiple access uplink systems. The proposed approach first estimates the carrier frequency offset (CFO) from the zeros of a backward prediction system. Then, based on the CFO estimates, two types of filters, namely zero-forcing and the linearly constrained minimum variance filters, are developed to suppress multiple access interference (MAI). Computer simulation results show that in addition to having a reduced computational complexity, the proposed algorithm has reliable CFO estimates and possesses at least a 3-dB power gain in MAI suppression over conventional minimum mean square error algorithms for frequency synchronization.

Subunit vaccines generally require adjuvants to achieve optimal immune responses. Toll-like receptor (TLR) agonists are promising immune potentiators, but rapid diffusion from the injection site reduces their local effective concentration and may cause systemic reactions. In this study, we investigated the potential of aluminum hydroxide adjuvant (AH) to adsorb the TLR3 agonist poly(I:C) and TLR9 agonist CpG and compared the effect of the combination adjuvant on the immune response with either the TLR agonists or AH alone in mice. Poly(I:C) and CpG readily adsorbed onto AH and this combination adjuvant induced a stronger IgG1 and IgG2a immune response with a significant increase of antibody avidity. The combination adjuvant enhanced antigen uptake and activation of dendritic cells in vitro. It induced an inflammatory response at the injection site similar to AH but without eosinophils which are typically observed with AH. A distinctive antigen-containing monocyte/macrophage population with an intermediate level of CD11c expression was identified in the draining lymph nodes after immunization with TLR agonists and the combination adjuvant. Injection of the combination adjuvant did not induce an increase of TNFα and CXCL10 in serum in contrast to the injection of soluble TLR agonists. These results indicate that this combination adjuvant is a promising formulation to solve some of the unmet needs of current vaccines.

Background Multidrug resistance (MDR) in cancer is one of the main obstacles in treatment with chemotherapy. Drug efflux through P-glycoprotein is the major mechanism involved in MDR. A potential strategy to provide the best possible clinical outcomes is to develop P-glycoprotein (P-gp) inhibitors from natural products. Purpose The present study investigated the effects of the natural sesquiterpene lactone tenulin and its derivative isotenulin on human P-gp; the mechanisms of kinetic interactions were also explored. Methods The human P-gp (ABCB1/Flp-In™-293) stable expression cells were established by using the Flp-In™ system. The effects of tenulin and isotenulin on cell viability were evaluated by SRB assays in established cell lines, sensitive cancer cell line (HeLaS3), and resistant cancer cell line (KB-vin). The transporter inhibition ability was evaluated by calcein-AM uptake assays. The P-gp inhibition kinetics of tenulin and isotenulin were evaluated by rhodamine123 and doxorubicin efflux assays. The ATPase activity was evaluated with the Pgp-Glo™ Assay System. Results Tenulin and isotenulin significantly inhibited the P-gp efflux function by stimulating P-gp ATPase activity. Tenulin and isotenulin interacted with the effluxes of rhodamine 123 and doxorubicin through a competitive and noncompetitive mechanism, respectively. The combinations of tenulin and isotenulin with chemotherapeutic drugs significantly resensitized MDR cancer cells. Conclusion These results suggested that tenulin and isotenulin are potential candidates to be developed for synergistic treatment of MDR cancers.

We report the effects of the growth temperature on the structural and electrical properties of the InAlGaN/GaN heterostructures grown on c-plane sapphire substrates. X-ray Photoelectron Spectroscopy and Atomic Force Microscopy measurements results indicate that the InAlGaN layer properties is strongly dependent on the growth temperature. It is observed that the Gallium incorporation increases with the increase of the growth temperature. Meanwhile, the surface roughness decreases from 0.49 nm to 0.34 nm with the increase of growth temperature. The variation of structural properties, composition and surface morphology influences the transport properties of the InAlGaN/GaN heterostructures. High 2DEG electron density, low sheet resistance and good C-V response with a steep slope for InAlGaN/GaN HEMT were achieved at an optimized growth temperature window between 900 °C and 950 °C.

This study presents a simple yet effective carrier frequency offset (CFO) estimation algorithm for orthogonal frequency division multiplexing (OFDM) systems. At the transmitter, the proposed algorithm uses null subcarriers to render the OFDM signal periodic in the time domain. At the receiver, these periodic time samples become CFO-bearing signals, which can be adopted to develop the maximum likelihood (ML) CFO estimation algorithm accordingly. In addition to providing reliable and efficient CFO estimation, the proposed algorithm has an adjustable acquisition region linearly proportional to the order of the null subcarrier insertion scheme.

Tigliane esters show many biological activities, including anti-HIV-1 activity. Our aim in this study was to establish structure-anti-HIV activity relationships for four series of tigliane-type diterpenoids. We synthesized and evaluated 29 new phorbol ester derivatives for anti-HIV activity and for cytotoxicity against human tumor cell lines. Among them, three derivatives, two phorbol-13-monoesters (5d and 5e) and a phorbol-12,13-diester (6a), showed significant anti-HIV activity. We found that better anti-HIV activity was often associated with a shorter acyl ester at C-13. Particularly, compounds with a phenyl ring in the ester side chain exhibited excellent anti-HIV activity and had good safety indexes. Due to its significant anti-HIV potency with a high selectivity index, phorbol-12,13-dicinnamoate (6a) was chosen as the potential candidate for further preclinical trials.

This study proposes a subspace-based inter-carrier interference (ICI) cancellation scheme for orthogonal-frequency-division-multiplexing (OFDM) systems. Conventional ICI cancellation methods suffer from the loss of spectral efficiency, and cannot handle the ICI incurred by a large frequency error. To improve the spectral efficiency, the proposed approach uses a subspace-based precoder that maps at most L − 1 data symbols to a group of L consecutive subcarriers. At the receiver, the proposed approach first coarsely estimate the frequency bias through a set of nulling filters each defined on a dedicated spectral bin. Then, based on the estimate of the frequency bias, the proposed approach uses subcarrier-combiners to eliminate intra-group interference. Computer simulations show that in addition to achieving a high spectral efficiency proportional to the precoder order, the proposed approach can effectively eliminate the ICI caused by a large-frequency-error.

Multi-segmented dsRNA viruses have been suggested to utilize cis-acting elements in the plus-strand RNA to accomplish genomic RNA assortment during viral packaging. It is not clear if bi-segmented dsRNA birnavirus uses the same strategy. By applying a reverse genetic technique, we generated IBDV particles packaged with only segment A by co-transfection DF-1 cells of cDNA from segment A and VP1 (without 5′ and 3′ noncoding region of segment B) supporting random assortment mechanism and indicating the packaging elements of segment B include sequences in the 5′ and 3′ NCR. However, gfp-containing IBDV could not be generated in the presence of gfp cDNA constructs flanked by 5′ and 3′ NCR from segment A or segment B. The data suggest additional packaging signals are required for IBDV genomic packaging. The presence of VP1 protein in the IBDV-A particles also suggests the formation of ribonucleoprotein (RNP) complexes might be involved in the assembly of viral particles.

This study presents an eigen-filter-based carrier-frequency-offset (CFO) estimation algorithm for orthogonal-frequency-division-multiple-access (OFDMA) uplinks. The proposed approach takes the periodic time samples of the OFDMA signal as the input of the filter that intends to eliminate the CFO signatures of all users. The wieght vector of the filter is attained from the null space of the input vectors under the criterion of minimum output power. Based on the zeros of the filter response, the proposed approach estimates the CFOs in a polynomial rooting way. This study analytically derives the mean square error (MSE) of the CFO estimates as well.

Green fluorescent protein (GFP) has been successfully incorporated into the viral-like particles of infectious bursal disease virus (IBDV) with a linker at the C-terminus of VP3 in a baculovirus system. However, when the same locus in segment A was used to express GFP by a reverse genetic (RG) system, no viable GFP-expressing IBDV was recovered. To elucidate the underlying mechanism, cDNA construct of segment A with only the linker sequence (9 amino acids) was applied to generate RG IBDV virus (rIBDV). Similarly, no rIBDV was recovered. Moreover, when the incubation after transfection was extended, wildtype rIBDV without the linker was recovered suggesting a free C-terminus of VP3 might be necessary for IBDV replication. On the other hand, rIBDV could be recovered when additional sequence (up to 40 nucleotides) were inserted at the 3’ noncoding region (NCR) adjacent to the stop codon of VP3, suggesting that the burden of the linker sequence was not in the stretched genome size but the disruption of the VP3 function. Finally, when the stop codon of VP3 was deleted in segment A to extend the translation into the 3’ NCR without introducing additional genomic sequence, no rIBDV was recovered. Our data suggest that a free VP3 C-terminus is essential for IBDV replication.

This paper presents the first full end-to-end deep learning framework for the swift prediction of lithium-ion battery remaining useful life. While lithium-ion batteries offer advantages of high efficiency and low cost, their instability and varying lifetimes remain challenges. To prevent the sudden failure of lithium-ion batteries, researchers have worked to develop ways of predicting the remaining useful life of lithium-ion batteries, especially using data-driven approaches. In this study, we sought a higher resolution of inter-cycle aging for faster and more accurate predictions, by considering temporal patterns and cross-data correlations in the raw data, specifically, terminal voltage, current, and cell temperature. We took an in-depth analysis of the deep learning models using the uncertainty metric, t-SNE of features, and various battery related tasks. The proposed framework significantly boosted the remaining useful life prediction (25X faster) and resulted in a 10.6% mean absolute error rate.

This paper presents an efficient carrier frequency offset (CFO) estimation algorithm for generalized frequency division multiplexing (GFDM) systems. The proposed algorithm formats the preamble into multiple identical subsymbols, and then decimates the received signal in the time domain to estimate the fractional CFO through array signal processing. After compensating for the fractional CFO, the proposed algorithm uses a low-complexity searching process to estimate the integer CFO in a maximum likelihood. The proposed algorithm presents some distinctive features: (1) it provides the full range of frequency acquisition region (FAR), which was considerably larger than that provided by many existing algorithms whose FAR was limited to one subcarrier spacing; (2) the proposed algorithm can use a single subsymbol to estimate the integer CFO by using the searching process of stepsize 1, significantly reducing its computational complexity; and (3) the decimation of the received signal ensures the proposed algorithm a power gain in fractional CFO estimation, resulting in an improved estimation accuracy compared with conventional algorithms.

Bioassay-guided fractionation of the n-butanol extract from the branches and leaves of Reutealis trisperma resulted in the isolation of six undescribed (crotignoids L ~ Q) together with two known (12-deoxyphorbol-13-hexadecanoate and 12-deoxyphorbol-13-myristate) tigliane diterpenoids. Their structures, especially the absolute configurations, were determined from extensive spectroscopic studies, including 2D NMR spectra, CD data analysis and electronic circular dichroism (ECD) calculations. All isolates were tested for anti-HIV activity against HL4-3 virus in MT4 cells. Except for crotignoid Q, the remaining seven tigliane diterpenoids exhibited potent anti-HIV activity with IC50 values ranging from 0.0023 to 4.03 μM.

The Hedgehog (Hh) pathway regulates cell differen- tiation and proliferation during development by controlling the Gli transcription factors. Cell fate de- cisions and progression toward organ and tissue maturity must be coordinated, and how an energy sensor regulates the Hh pathway is not clear. AMP- activated protein kinase (AMPK) is an important sensor of energy stores and controls protein synthe- sis and other energy-intensive processes. AMPK is directly responsive to intracellular AMP levels, inhib- iting a wide range of cell activities if ATP is low and AMP is high. Thus, AMPK can affect development by influencing protein synthesis and other processes needed for growth and differentiation. Activation of AMPK reduces GLI1 protein levels and stability, thus blocking Sonic-hedgehog-induced transcrip- tional activity. AMPK phosphorylates GLI1 at serines 102 and 408 and threonine 1074. Mutation of these three sites into alanine prevents phosphorylation by AMPK. This leads to increased GLI1 protein stability, transcriptional activity, and oncogenic potency.

This work develops a new reference electrode for the electrochemical system using an aqueous supercritical carbon dioxide (sc-CO2) emulsion solutions. Here, the Watts nickel bath is employed to be the standard testing electrolyte. A porous Pd-coated Ti (denoted as Pd/Ti) electrode is prepared by electroplating, which is subjected to the hydrogen sorption (including adsorption and absorption) reaction in 0.5 M H2SO4 for forming a palladium hydride-coated titanium (denoted as PdHx/Ti) electrode. The hydrogen sorption/desorption behavior on Pd/Ti is characterized by cyclic voltammetry and rest potential against time analyses. These results reveal that PdHx/Ti is a reliable reference electrode with a reproducible and stable PdHx potential (longer than 10 h) in normal aqueous electrolytes at room temperature. The equilibrium potential of this PdHx/Ti electrode is about 65 ± 15 mV (vs. RHE) in the Watts Ni bath. Although the hydrogen desorption rate is enhanced by elevating the solution temperature, all of the results confirm that the in-situ formed PdHx/Ti electrode can be practically utilized as a reference electrode in the Watts Ni bath containing the sc-CO2 emulsion medium.

DNA vaccine coding for infectious bursal disease virus (IBDV) polyprotein gene and that for avian influenza virus (AIV) hemagglutinin (HA) gene have been shown to induce immunity and provide protection against the respective disease. The present study was carried out to determine whether an IBDV polyprotein gene-based DNA fused with AIV HA gene could trigger immune response to both IBDV and AIV. After transfection, VP2 and HA were detected in the cytoplasm and at cell membrane, respectively, by immunofluorescent antibody double staining method, suggesting the fusion strategy did not affect the location of protein expression. VP4 cleavage between VP2 and HA was confirmed by Western blot, indicating the fusion strategy did not affect VP4 function in transfected cells. After vaccination in chickens, the DNA construct VP24-HA/pcDNA induced ELISA and virus neutralizing antibodies against VP2 and hemagglutination inhibition antibody against the HA subtype. The results indicated that a single plasmid construct carrying IBDV VP243 gene-based DNA fused with AIV HA gene can elicit specific antibody responses to both IBDV and AIV by DNA vaccination.

Proportional fair scheduling (PFS) and its variants have been widely deployed in 3G/4G systems, where base stations (BSs) use channel quality indicator (CQI) from users as a channel feedback. Series of recent papers have shown that PFS may not perform as expected, when these client-side feedbacks such as CQI or NACK are fabricated. These results, however, were obtained without considering all relevant components in practice that are designed to handle various corner cases. In this paper, we revisit the impact of CQI and NACK fabrications, and also the fabrication of ACK (which has been largely ignored in prior work), by jointly considering all known components such as adaptive modulation and coding (AMC), hybrid automatic repeat request (HARQ), outer loop link adaptation (OLLA) and PFS as a whole. To consider many practical fabrication scenarios, we study both cases when only a single feedback and a smart combinations of multi-feedbacks are exploited for selfish and/or malicious purposes. From these studies, we draw in-depth findings with large practical implications, most of which are in sharp contrast to those in prior work on the security of PFS.

This study presents an efficient carrier-frequency-offset (CFO) and symbol-timing-offset (STO) estimation algorithm for time-dispersive orthogonal frequency division multiplexing (OFDM) system using a general inter-carrier interference (ICI) self-cancellation scheme. This study takes advantage of the time shift invariant property in the precoded signal to estimate the CFO. The proposed algorithm first stacks the receive time samples spaced by a pre-determined time interval into sample vectors, which can be expressed in a form having a CFO-directed response vector. This CFO-directed structure enables the proposed approach to estimate the CFO by using the multiple signal classification (MUSIC) algorithm in the time domain. Equalization is required before the MUSIC algorithm to remove the scaling factor generated in the signal stacking. Using the CFO estimate, the proposed approach compensates for the frequency error in the receive signal and then estimates the STO by invoking the MUSIC algorithm in the frequency domain. Unlike conventional algorithms, in addition to having a larger CFO estimation range linearly proportional to the precoding order, the proposed approach can easily handle the case of fractional STO. This study presents some statistical analysis of the undesired equalization residues and the mean square error of the perturbed MUSIC algorithm to provide further insights into the proposed approach.

Conventional ICI self-cancellation methods are spectral consuming because they modulate a single data on a group of subcarriers. To improve the spectral efficiency, the proposed approach uses a kernel-based precoder that maps at most L-1 data symbols to a group of L consecutive subcarriers. On the receive side, the carrier-frequency-offset-directed (CFO-directed) structure of the precoded signal enables the proposed approach to estimate the CFO in the frequency domain. Then, based on this CFO estimate, the proposed approach develops a set of constrained-subcarrier-combiners (CSC) to eliminate intra-group interference. Computer simulations show that in addition to achieving a high spectral efficiency proportional to the precoder order, the proposed approach can effectively eliminate the ICI caused by a large-frequency-error because of the CSC. HighlightsThis study presents a kernel-based precoder of high spectral efficiency.The kernel-based precoder suppresses the inter-group-interference at the transmitter.Subcarrier combiners are employed to mitigate the intra-group interference at the receiver.This study estimates the CFO in the frequency domain through a subspace-based algorithm.

This study proposes a polynomial-rooting algorithm to estimate the carrier-frequency-offset (CFO) of a slow fading orthogonal frequency division multiplexing (OFDM) system. The proposed algorithm uses an inter-carrier-interference self-cancellation (ICI-SC) scheme to precode data symbols at the transmitter. This study derives the time coherency of the precoded OFDM signal, which enables the proposed algorithm to estimate the CFO through array signal processing techniques. The proposed algorithm first constructs snapshot vectors using the receive time samples at specific positions. This snapshot vector is CFO-directed because of the coherent property of the precoded signal. Using the second order statistics of the snapshot vector, the proposed approach estimates the CFO through a polynomial-rooting algorithm.

This paper presents a simple yet effective carrier-frequency-offset (CFO) estimation algorithm for orthogonal-frequency-division-multiplexing (OFDM) system using a general inter-carrier interference (ICI) self-cancellation scheme. The key feature of the proposed algorithm is that it has a significantly wider CFO estimation range than the maximum-likelihood (ML) algorithm. The proposed algorithm first constructs the snapshot vectors through stacking the signals in each subcarrier group of the precoded OFDM symbol. Because the ICI self-cancellation scheme can suppress the inter-group ICIs, the snapshot vectors can be expressed in a form having a CFO-directed response structure. This enables the proposed approach to estimate the CFO by using the multiple signal classification (MUSIC) algorithm in the frequency domain.

Delay Tolerant Networks (DTNs) are characterized by intermittently connected links formed by mobile nodes' probabilistic encounters. Most DTN routing techniques use the first encountered node who has smaller routing metric as a relay node. Prior work on DTN routing can be broadly classified into one which takes the minimum out of expected delays for all possible individual routing paths, referred to as MinEx, as a routing metric to decide the next hop relay node. Fundamentally, MinEx has no difference from the shortest path computation in conventional multi-hop networks, where a link weight is the expected inter-meeting time. However in DTNs, nodes meet intermittently by their mobility, hence the links formed from the meetings are probabilistic. In this environment, MinEx often fails to accurately estimate the actual delay since opportunism in nodes' intermittent meeting is not properly taken into account. In this paper, to exploit the true opportunism, we first propose a metric called ExMin which stochastically calculates the metric by taking the expectation of the minimum delays over all possible routes. We further show that ExMin can be computed online by relying only on local information sharing. Our extensive experiments involving three realistic network scenarios created by two vehicle traces (about 1500 Shanghai taxies and 500 San Francisco taxies) and one human mobility trace (93 KAIST students) show that ExMin outperforms MinEx by up to 30% under either of DTN environments allowing single-copy or multi-copies of a packet.

This study proposes a per-survivor based BCJR algorthm for joint frequency synchronization and data decoding in trellis coded modulation (TCM) systems. The proposed algorithm uses two probing signals and a carrier frequency offset (CFO) tracker to calculate the modified gamma factor involved in the BCJR algorithm. To track the CFO, a state-time process recursively updates the CFO tracker using the soft-information provided by the modified gamma factor. The state-time process consists of a state-process and a time-process. The state-process takes advantage of the state-diversity in the TCM signals to choose the most probable CFO update corresponding to the state with the maximal modified gamma factor. Based on this CFO value, and in conjunction with the tentatively selected probing signals, the succeeding time-process can iteratively track the CFO using the trellis structure of the TCM signals. This study also develops a least-square-linear-fitting (LSLF) approach based on the CFO trace to dynamically adjust the step-size for the CFO tracker. Computer simulations show that unlike the conventional augmented a posteriori probability (A 2 P 2 ) method having a small CFO tracking range, the proposed approach can handle a significantly larger CFO because of its ML-based CFO estimate. In addition, the proposed LSLF step-size determination ensures the PS-BCJR a higher accuracy in CFO estimation than the A 2 P 2 .

The conventional per-survivor-processing (PSP) scheme suffers from the error propagation problem because it does not fully use the state message provided by a hidden Markov process. This study proposes a vertical cooperation among states to enhance the estimate reliabilities in the PSP scheme. The key idea of the proposed algorithm is to estimate the system uncertainty at each time stage in a maximum likelihood (ML) manner that chooses the parameter estimate of the state with the minimum cumulative branch metric as the survival estimate of the time stage. Computer simulations show that with the improved phase estimates, the proposed algorithm significantly outperforms the conventional PSP scheme in data decoding.

New 6- (or 6,7-) substituted 2-(hydroxyl substituted phenyl)quinolin-4-one derivatives were synthesized and screened for antiproliferative effects against cancer cell lines. Structure-activity relationship correlations were established and the most promising compound 2-(3-hydroxy-5-methoxyphenyl)-6-pyrrolidin-1-ylquinolin-4-one (6h) exhibited strong inhibitory activity against various human cancer cell lines, particularly non-small cell lung cancer NCI-H522. Additional studies suggested a mechanism of action resembling that of the antimitotic drug vincristine. The presence of a C-ring OH group in 6h will allow this compound to be converted readily to a water soluble and physicochemically stable hydrophilic prodrug. Compound 6h is proposed as a new anticancer lead compound.

Network virtualization is a technology of running multiple heterogeneous network architecture on a shared substrate network. One of the crucial components in network virtualization is virtual network embedding, which provides a way to allocate physical network resources (CPU and link bandwidth) to virtual network requests. Despite significant research efforts on virtual network embedding in wired and cellular networks, little attention has been paid to that in wireless multi-hop networks, which is becoming more important due to its rapid growth and the need to share these networks among different business sectors and users. In this paper, we first study the root causes of new challenges of virtual network embedding in wireless multi-hop networks, and propose a new embedding algorithm that efficiently uses the resources of the physical substrate network. We examine our algorithm's performance through extensive simulations under various scenarios. Due to lack of competitive algorithms, we compare the proposed algorithm to five other algorithms, mainly borrowed from wired embedding or artificially made by us, partially with or without the key algorithmic ideas to assess their impacts., Comment: 22 pages

6,7-Methylenedioxy (or 5-hydroxy-6-methoxy)-2-(substituted selenophenyl)quinolin-4-ones and their isosteric compounds were synthesized and evaluated for anticancer activity. Structure–activity relationships (SAR) of these compounds were established. Among all tested compounds, 6,7-methylenedioxy-2-(5-methylselenophen-2-yl)quinolin-4-one (4d) was found to be the most promising anticancer agent. In screening against NCI’s 60 human tumor cell line panel, 4d exhibited highly selective and potent inhibitory activity against MDA-MB-435 melanoma. Furthermore, the results of COMPARE analysis suggested that 4d is an antimitotic agent with a different mechanism of action from the conventional antimitotic agents, such as colchicine, vinca alkaloids and paclitaxel. Therefore, 4d was identified as a new lead compound that merits further optimization.