535 research outputs found

    Effects of Atypical Neurotoxins on the Developing Fetal Brain

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    The brain is not only a control center of the body but also a part of the way that the body can communicate with external environments. The spatial and temporal events of brain development are well-defined. These processes are sequentially regulated by intrinsic and external factors, such as gene. Disruption of these steps results in malformation and malfunction of the brain. Neurotoxin may affect our developing nervous system as a kind of endogenous and exogenous factor. For classical neurotoxins, such as heavy metals, snake venom, and bacterial toxins, the underlying toxin-mediated physiological pathways are relatively clear, and their antidotes are usually available. However, for atypical neurotoxins, such as air pollutants, food additives, and manufactural compounds, their effects on the nervous system are ordinarily extended and not easy to detect. In addition, the corresponding mechanism is too complex to define. A single and effective antidote against these atypical neurotoxins is uncommon, so prevention is better than cure with this kind of toxin. This chapter starts with the introduction of endogenous and exogenous neurotoxins, how they affect nervous system and their potential antidotes, followed by the impact of atypical neurotoxins in fetal brain development and their possible preventative or therapeutic methods

    Selected Cello Sonatas from 1880-1950: Tradition and Innovation

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    In the Romantic era, composers were inspired to experiment and to expand the wide range of colors, dynamics, registers, and musical vocabularies of all instruments, including strings, because of a growing emphasis on virtuosity and brilliance among performers. Cello sonatas therefore started to emerge and evolve in many different and exciting ways. The goal of this performance project was to broaden my familiarity with the sonata genre, as well as to discover both the traditional and innovative sides of the selected cello sonatas from 1880 to 1950, using the sonatas of Brahms, Franck, Poulenc, Rachrnaninoff, Shostakovich, and Strauss. The following is the list of sonatas 1 presented on three dissertation recitals in Gildenhorn Recital Hall. These public performances were recorded on compact disc

    On Optimizing Signaling Efficiency of Retransmissions for Voice LTE

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    The emergence of voice over LTE enables voice traffic transmissions over 4G packet-switched networks. Since voice traffic is characterized by its small payload and frequent transmissions, the corresponding control channel overhead would be high. Semi-persistent scheduling (SPS) is hence proposed in LTE-A to reduce such overhead. However, as wireless channels typically fluctuate, tremendous retransmissions due to poor channel conditions, which are still scheduled dynamically, would lead to a large overhead. To reduce the control message overhead caused by SPS retransmissions, we propose a new SPS retransmission protocol. Different from traditional SPS, which removes the downlink control indicators (DCI) directly, we compress some key fields of all retransmissions' DCIs in the same subframe as a fixed-length hint. Thus, the base station does not need to send this information to different users individually but just announces the hint as a broadcast message. In this way, we reduce the signaling overhead and at the same time, preserve the flexibility of dynamic scheduling. Our simulation results show that, by enabling DCI compression, our design improves signaling efficiency by 2.16\times, and the spectral utilization can be increased by up to 60%

    Hey! I Have Something for You: Paging Cycle Based Random Access for LTE-A

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    The surge of M2M devices imposes new challenges for the current cellular network architecture, especially in radio access networks. One of the key issues is that the M2M traffic, characterized by small data and massive connection requests, makes significant collisions and congestion during network access via the random access (RA) procedure. To resolve this problem, in this paper, we propose a paging cycle-based protocol to facilitate the random access procedure in LTE-A. The high-level idea of our design is to leverage a UE's paging cycle as a hint to preassign RA preambles so that UEs can avoid preamble collisions at the first place. Our rpHint has two modes: (1) collision-free paging, which completely prevents cross-collision between paged user equipment (UEs) and random access UEs, and (2) collision-avoidance paging, which alleviates cross-collision. Moreover, we formulate a mathematical model to derive the optimal paging ratio that maximizes the expected number of successful UEs. This analysis also allows us to adapt dynamically to the better one between the two modes. We show via extensive simulations that our design increases the number of successful UEs in an RA procedure by more than 3× as compared to the legacy RA scheme of the LTE

    A novel glue attachment approach for precise anchoring of hydrophilic EGCG to enhance the separation performance and antifouling properties of PVDF membranes

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    A novel glue attachment approach was proposed to form a durable hydration layer on a hydrophobic PVDF hollow fiber membrane (PVDF HFM) surface to improve its hydrophilicity and antifouling ability during wastewater filtration. The functional glue was synthesized from reclaimed styrene butadiene rubber (SBR) and a hydroxyl group was created with an epoxidation reaction (ESBR). The hydrophilic epigallocatechin-s-gallate (EGCG) was then precisely anchored via hydrogen bonding with multiple phenolic hydroxyl groups in the ESBR without penetrating into the inner matrix of the PVDF to prevent flux decline. The hydrophilicity of the PVDF membrane increased drastically and the water contact angle decreased from 62.7° to 45.1° with only a 25% decline in the pure water flux. Furthermore, due to precise anchoring of the EGCG, the modified EGCG-ESBR/PVDF membrane showed a higher pure water flux (110.6 L m−2h−1) and much higher BSA and oil (kerosene) rejection rates (approximately 94.5% and 99.5%, respectively) compared to membranes directly coated with EGCG (EGCG-PVDF). Moreover, the modified membrane also showed higher water flux recovery after multiple filtration cycles. This promising and efficient hydrophilic modification suggests great potential for application of the eco-friendly material in wastewater treatment.</p

    Local Implicit Normalizing Flow for Arbitrary-Scale Image Super-Resolution

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    Flow-based methods have demonstrated promising results in addressing the ill-posed nature of super-resolution (SR) by learning the distribution of high-resolution (HR) images with the normalizing flow. However, these methods can only perform a predefined fixed-scale SR, limiting their potential in real-world applications. Meanwhile, arbitrary-scale SR has gained more attention and achieved great progress. Nonetheless, previous arbitrary-scale SR methods ignore the ill-posed problem and train the model with per-pixel L1 loss, leading to blurry SR outputs. In this work, we propose "Local Implicit Normalizing Flow" (LINF) as a unified solution to the above problems. LINF models the distribution of texture details under different scaling factors with normalizing flow. Thus, LINF can generate photo-realistic HR images with rich texture details in arbitrary scale factors. We evaluate LINF with extensive experiments and show that LINF achieves the state-of-the-art perceptual quality compared with prior arbitrary-scale SR methods.Comment: CVPR 2023 camera-ready versio

    In-Band Asymmetry Compensation for Accurate Time/Phase Transport over Optical Transport Network

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    The demands of precise time/phase synchronization have been increasing recently due to the next generation of telecommunication synchronization. This paper studies the issues that are relevant to distributing accurate time/phase over optical transport network (OTN). Each node and link can introduce asymmetry, which affects the adequate time/phase accuracy over the networks. In order to achieve better accuracy, protocol level full timing support is used (e.g., Telecom-Boundary clock). Due to chromatic dispersion, the use of different wavelengths consequently causes fiber link delay asymmetry. The analytical result indicates that it introduces significant time error (i.e., phase offset) within 0.3397 ns/km in C-band or 0.3943 ns/km in L-band depending on the wavelength spacing. With the proposed scheme in this paper, the fiber link delay asymmetry can be compensated relying on the estimated mean fiber link delay by the Telecom-Boundary clock, while the OTN control plane is responsible for processing the fiber link delay asymmetry to determine the asymmetry compensation in the timing chain

    Identification of the genetic determinants of Salmonella enterica serotype Typhimurium that may regulate the expression of the type 1 fimbriae in response to solid agar and static broth culture conditions

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    <p>Abstract</p> <p>Background</p> <p>Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of <it>Salmonella enterica </it>serotype Typhimurium. Previous investigations indicate that static broth culture favours <it>S</it>. Typhimurium to produce type 1 fimbriae, while non-fimbriate bacteria are obtained by growth on solid agar media. The phenotypic expression of type 1 fimbriae in <it>S</it>. Typhimurium is the result of the interaction and cooperation of several genes in the <it>fim </it>gene cluster. Other gene products that may also participate in the regulation of type 1 fimbrial expression remain uncharacterized.</p> <p>Results</p> <p>In the present study, transposon insertion mutagenesis was performed on <it>S</it>. Typhimurium to generate a library to screen for those mutants that would exhibit different type 1 fimbrial phenotypes than the parental strain. Eight-two mutants were obtained from 7,239 clones screened using the yeast agglutination test. Forty-four mutants produced type 1 fimbriae on both solid agar and static broth media, while none of the other 38 mutants formed type 1 fimbriae in either culture condition. The flanking sequences of the transposons from 54 mutants were cloned and sequenced. These mutants can be classified according to the functions or putative functions of the open reading frames disrupted by the transposon. Our current results indicate that the genetic determinants such as those involved in the fimbrial biogenesis and regulation, global regulators, transporter proteins, prophage-derived proteins, and enzymes of different functions, to name a few, may play a role in the regulation of type 1 fimbrial expression in response to solid agar and static broth culture conditions. A complementation test revealed that transforming a recombinant plasmid possessing the coding sequence of a NAD(P)H-flavin reductase gene <it>ubiB </it>restored an <it>ubiB </it>mutant to exhibit the type 1 fimbrial phenotype as its parental strain.</p> <p>Conclusion</p> <p>Genetic determinants other than the <it>fim </it>genes may involve in the regulation of type 1 fimbrial expression in <it>S</it>. Typhimurium. How each gene product may influence type 1 fimbrial expression is an interesting research topic which warrants further investigation.</p
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