210 research outputs found
Generalized DFT: extensions in communications
Discrete Fourier Transform (DFT) is a restricted version of Generalized DFT (GDFT) which offers a very limited number of sets to be used in a multicarrier communication system. In contrast, as an extension on Discrete Fourier Transform (DFT) from the linear phase to non-linear phase, the proposed GDFT provides many possible carrier sets of various lengths with comparable or better performance than DFT. The availability of the rich library of orthogonal constant amplitude transforms with good performance allows people to design adaptive systems where user code allocations are made dynamically to exploit the current channel conditions in order to deliver better performance.
For MIMO Radar systems, the ideal case to detect a moving target is when all waveforms are orthogonal, which can provide an accurate estimation. But this is not practical in distributed MIMO radars, where sensors are at varying distances from a target. Orthogonal waveforms with low auto- and cross-correlations are of great interest for MIMO radar applications with distributed antennas. Finite length orthogonal codes are required in real-world applications where frequency selectivity and signal correlation features of the optimal subspace are compromised. In the first part of the dissertation, a method is addressed to design optimal waveforms which meets above requirements for various radar systems by designing the phase shaping function (PSF) of GDFT framework with non-linear phase.
Multicarrier transmission such as orthogonal frequency-division multiplexing (OFDM) has seen a rise in popularity in wireless communication, as it offers a promising choice for high speed data rate transmission. Meanwhile, high peak-to-average power ratio (PAPR) is one of the well-known drawbacks of the OFDM system due to reduced power efficiency in non-linear modules. Such a situation leads to inefficient amplification and increases the cost of the system, or increases in interference and signal distortion. Therefore, PAPR reduction techniques play an essential role to improve power efficiency in the OFDM systems. There has been a variety of PAPR reduction methods emphasizing different aspects proposed in the literature. The trade-off for PAPR reduction in the existing methods is either increased average power and/or added computational complexity. A new PAPR reduction scheme is proposed that implements a pre-designed symbol alphabet modifier matrix (SAM) to jointly modify the amplitude and phase values of the original data symbol alphabets prior to the IFFT operation of an OFDM system at the transmitter. The method formulated with the GDFT offers a low-complexity framework in four proposed cases devised to be independent of original data symbols. Without degrading the bit error rate (BER) performance, it formulates PAPR reduction problem elegantly and outperforms partial transmit sequences (PTS), selected mapping technique (SLM) and Walsh Hadamard transform (WHT-OFDM) significantly for the communication scenarios considered in the dissertation
N-(1-Naphthyl)benzenesulfonamide
In the title compound, C16H13NO2S, the C—SO2—NH—C torsion angle is −70.1 (2)°. The dihedral angle between the planes of the naphthyl ring system and the phenyl ring is 34.67 (4)°. In the crystal, molecules are linked by intermolecular N—H⋯O hydrogen bonds into chains along [100]. There are also π–π interactions between adjacent naphthyl groups [interplanar spacing = 3.541 (3) Å] for molecules stacked along [100]
Tri-MipRF: Tri-Mip Representation for Efficient Anti-Aliasing Neural Radiance Fields
Despite the tremendous progress in neural radiance fields (NeRF), we still
face a dilemma of the trade-off between quality and efficiency, e.g., MipNeRF
presents fine-detailed and anti-aliased renderings but takes days for training,
while Instant-ngp can accomplish the reconstruction in a few minutes but
suffers from blurring or aliasing when rendering at various distances or
resolutions due to ignoring the sampling area. To this end, we propose a novel
Tri-Mip encoding that enables both instant reconstruction and anti-aliased
high-fidelity rendering for neural radiance fields. The key is to factorize the
pre-filtered 3D feature spaces in three orthogonal mipmaps. In this way, we can
efficiently perform 3D area sampling by taking advantage of 2D pre-filtered
feature maps, which significantly elevates the rendering quality without
sacrificing efficiency. To cope with the novel Tri-Mip representation, we
propose a cone-casting rendering technique to efficiently sample anti-aliased
3D features with the Tri-Mip encoding considering both pixel imaging and
observing distance. Extensive experiments on both synthetic and real-world
datasets demonstrate our method achieves state-of-the-art rendering quality and
reconstruction speed while maintaining a compact representation that reduces
25% model size compared against Instant-ngp.Comment: Accepted to ICCV 2023 Project page:
https://wbhu.github.io/projects/Tri-MipR
Molecular cloning and characterisation of scavenger receptor class B in pearl oyster Pinctada fuctada martensii
Background: Molluscs can accumulate carotenoids in their body tissues
by predominantly feeding on aquatic plant sources. Carotenoid transport
and absorption are determined by the regulation of various proteins
such as Scavenger receptor class B(SR-BI). We report the identification
and characterisation of pearl oyster Pinctada fuctada martensii SR-BI
(PmSR-BI). The correlation between total carotenoid content (TCC) and
gene expression was also estimated. Results: The full-length cDNA of
PmSR-BI was 1828 bp, including an open-reading frame encoding of 1518
bpwith a pI value of 5.83. PmSR-BI protein contains a hydrophobic CD36
domain and four centrally clustered cysteine residues for the
arrangement of disulphide bridges. The deduced amino acid sequence had
an identity of 30% to 60% with the SR-B of other organisms. Reverse
transcription polymerase chain reaction analysis showed that mRNA
transcripts were expressed in multiple tissues of adult pearl oyster. A
higher expression of PmSR-BI gene was observed in the hepatopancreas
than in the adductor muscle, gill and mantle. The TCC and gene
expression of PmSR-BI were significantly correlated (P < 0.05), with
a correlation coefficient of 0.978. Conclusions: The results suggested
that PmSR-BI is involved in the absorption of carotenoids in the pearl
oyster P. fuctada martensii
Effect of tea polyphenols on intestinal barrier and immune function in weaned lambs
IntroductionThe purpose of this study was to explore the effects of tea polyphenols on growth performance, cytokine content, intestinal antioxidant status and intestinal barrier function of lambs, in order to provide reference for intestinal health of ruminants.MethodsThirty weaned lambs (average initial weight 9.32 ± 1.72 kg) were randomly divided into five groups with six lambs in each group. The control group did not add anything but the basic diet mainly composed of Pennisetum and Corn, and the other four groups added 2, 4, 6 g/kg tea polyphenols and 50 mg/kg chlortetracycline to the basic diet, respectively. The experiment lasted for 42 days.ResultsDietary tea polyphenols improved the growth and stress response and reduced intestinal permeability of lambs (p > 0.05), while CTC did not affect the final lamb weight (p > 0.05). Both tea phenols and CTC significantly reduced inflammatory factors and enhanced the immune system (p > 0.05). Dietary tea polyphenols increased villus height, villus height/crypt depth, secretory immunoglobulin A (p > 0.05), and antioxidant enzymes, while decreasing MDA and apoptosis in the intestine (p > 0.05). However, compared with other groups, the content of T-AOC in jejunum did not change significantly (p > 0.05). Tea polyphenols also increased claudin-1 levels in the duodenum, jejunum, and ileum more than CTC (p > 0.05). CTC had a limited effect on the mRNA expression of Occludin and ZO-1, while tea polyphenols increased these in both the duodenum and ileum (p > 0.05).ConclusionThis study demonstrated that tea polyphenols can effectively improve the intestinal barrier of weaned lambs, and that they have anti-inflammatory and antioxidant effects similar to those of antibiotics. Thus, tea polyphenols could be used to replace antibiotics in ensuring safety of livestock products and in achieving the sustainable development of modern animal husbandry
Development of SSR marker by RNA-seq and its application in genotyping pearl sac in pearl oyster Pinctada fucata martensii
Background: Pearl oyster Pinctada fucata martensii is cultured for
producing round nucleated pearls. Pearl production involves a surgical
operation where a mantle tissue graft from a donor oyster and a round
nucleus are implanted in the gonad of a host oyster. Whether the mantle
graft implanted in the gonad of a host oyster contributes to the
formation of a pearl sac that secretes pearl nacre to form a pearl
should be determined. In April 2012, two full-sib families were
separately used as donor and host oysters for a nucleus insertion
operation. The pearl sac was sampled from the host oysters at day 60
after nucleus operation. A large number of simple sequence repeat (SSR)
markers were developed using Illumina HiSeq\u2122 2000 platform. The
two full-sib families were also used to mine diagnostic SSR markers for
genotyping donor oyster, host oyster, and pearl sac. Results: A total
of 3168 microsatellite lociwere identified in 39,078 unigenes, and 1977
SSR primerswere designed by Primer 3.0. Forty-seven SSR primers were
validated, and the rate of successful amplification was 72.3%. Two
diagnostic SSR primers could successfully genotype pearl sac, donor
oyster, and host oyster. Donor and host oysters were both homogenous,
and the alleles in pearl sac were identical to those in donor and host
oysters. Conclusions: The present results confirmed that themantle
graft implanted in the gonad of host oyster contributed to the
formation of the pearl sac in pearl oyster P. fucata martensii
Elevation of YKL-40 in the CSF of Anti-NMDAR Encephalitis Patients Is Associated With Poor Prognosis
Objective: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis predominantly affects children and young women; the disease can have a multistage presentation and exhibit a wide variety of neuropsychiatric features. This study aimed to investigate the profile of YKL-40 (Chitinase 3-like 1) in anti-NMDAR encephalitis patients and evaluate its association with modified Rankin Scale (mRS) scores and expression of inflammatory cytokines.Methods: A total of 66 patients were enrolled in this study, 33 with anti-NMDAR encephalitis, 13 with viral meningitis and 20 with non-inflammatory neurological disease. Patients were evaluated to determine mRS scores at disease onset and at the 3 month follow-up; cerebrospinal fluid (CSF) samples were collected in the meantime. CSF levels of YKL-40 and cytokines (TNF-α, IL-6, IL-10) were measured by enzyme-linked immunosorbent assay.Results: CSF levels of YKL-40 and inflammatory cytokines (TNF-α, IL-6, IL-10) were all more highly elevated in patients with anti-NMDAR encephalitis at the acute stage of disease compared with the controls. Levels of CSF YKL-40 were correlated with levels of IL-6 both at disease onset and at the 3 month follow-up. Changes in YKL-40 levels were significantly correlated with improved mRS scores in patients with anti-NMDAR encephalitis.Conclusion: Our study suggests that CSF levels of YKL-40 in patients with anti-NMDAR encephalitis were increased and correlated with clinical mRS scores. This may be reflective of the underlying neuroinflammatory process. YKL-40 demonstrates potential as a possible biomarker for the prognosis of anti-NMDAR encephalitis
EFFECTS OF CIJI HUA’AI BAOSHENG FORMULA ON APOPTOSIS CORRELATION FACTORS OF TUMOR CHEMOTHERAPY MODEL MOUSE WITH H22 HEPATOMA CARCINOMA CELLS
Background: Ciji Hua’ai Baosheng Formula (CHBF) is a traditional Chinese empirical formula that can help the tumor patients who received chemotherapy to antagonize the toxin and side-effects so as to improve and prolong the life. This study is to evaluate the effects of Ciji Hua’ai Baosheng Formula on apoptosis correlation factors of transplanted tumor chemotherapy model mouse with H22 hepatoma carcinoma cells through detecting the protein level of serum Bax, Bcl-2, Caspase-3, epidermal growth factor receptor (EGFR) and the protein expression of CyclinD1 in femur bone marrow.
Materials and Methods: H22 hepatoma carcinoma cells were cultivated and diluted to 2×107/ml, and a total of 50 specific pathogen-free Kunming mice were injected subcutaneously into the right anterior armpit with H22 hepatoma carcinoma cells, after 7 days, all mice had formed tumors and were used peritoneal injection of Cytoxan (CTX) (200mg/kg) to establish the mouse chemotherapy model with transplanted tumor, then they were randomly divided into 5 groups such as model, positive control (CTX, 0.033g/kg) and three CHBF (117g/kg, 58.5g/kg and 29.25g/kg) groups with 10 mice in each group. They were administered next day after making model. Survival state was observed. After administering for 10 days, pathological tissue structural change was detected by light microscope, blood was collected through pricking eyeball, protein level of serum Bax, Bcl-2, Caspase-3 and EGFR was detected by enzyme-linked immunosorbent assay (ELISA), the protein expression of CyclinD1 in femur bone marrow was detected by immunohistochemisty.
Results: Under the light microscope, the deteriorated degree of tumor tissue and the proliferation degree of tumor cells in three CHBF groups were obviously milder than that of model group. The protein content of the pro-apoptotic gene Bax and effective enzyme Caspase-3 in CHBF (58.5g/kg and 29.25g/kg) groups were obviously higher than that of model groups (
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