129 research outputs found

    Volume holographic recording in nanoparticle–polymer composites doped with multifunctional chain transfer agents

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    We report on an experimental investigation of the properties of volume holographic recording in photopolymerizable nanoparticle–polymer composites (NPCs) doped with chain transferring multifunctional di- and tri-thiols as chain transfer agents. It is shown that the incorporation of the multifunctional thiols into NPCs more strongly influences on volume holographic recording than that doped with mono-thiol since more chemical reactions involve in the polymer network formation. It is found that, as similar to the case of mono-thiol doping, there exist optimum concentrations of di- and tri-thiols for maximizing the saturated refractive index modulation. It is also seen that recording sensitivity monotonically decreases with an increase in multifunctional thiol concentration due to the partial inhibition of the photopolymerization event by excessive thiols

    Photopolymers for Use as Holographic Media

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    In this chapter we briefly review some of the developments which have been made in the area of photopolymer material development for applications such as holography. We also examine some of the extensions which have been made to the theoretical models of the processes which occur during free radical photo-polymerisation, namely the Non-local Photo-polymerisation Driven Diffusion (NPDD) model. An understanding of these photochemical and photo-physical processes is of extreme importance when attempting to improve a photopolymer material’s performance for a given application. We will explore the most recent developments made and illustrate some of the useful trends, which this NPDD model predicts and then analyze their implications on photopolymer improvement. Among the effects examined are; the temporal and spatial primary radical generation (the driving force of photo-polymerisation), multiple termination mechanisms, non-local polymer chain growth, the effects of oxygen inhibition, mass transport effects (diffusion), dark reactions (post exposure effects) and chain transfer, to name a few

    Value of 18F-PSMA PET/MRI for early diagnosis of recurrence and metastasis in prostate cancer patients after radical prostatectomy

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    Objective: To investigate the value and significance of 18F-prostate-specific membrane antigen (18F-PSMA)-1007 PET/MR for early diagnosis of recurrence and metastasis in prostate cancer patients after radical prostatectomy (RP). Methods: A total of 143 patients with prostate cancer after radical prostatectomy were enrolled during June 2019 to January 2022 in Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. All the patients underwent 18F-PSMA-1007 PET/MR imaging within 12 to 60 months after surgery. According to the serum prostate-specific antigen (PSA) levels, patients were divided into 5 groups(PSA≤0.2 ng/mL, 0.2 ng/mL<PSA≤0.5 ng/mL, 0.5 ng/mL<PSA≤4.0 ng/mL, 4.0 ng/mL<PSA<10.0 ng/mL and PSA≥10.0 ng/mL). The detection rates of recurrence or metastasis were compared between different groups. Results: The detection rates of 18F-PSMA-1007 PET/MR for recurrence or metastasis in PSA≤0.2 ng/mL, 0.2 ng/mL<PSA≤0.5 ng/mL, 0.5 ng/mL< PSA ≤ 4.0 ng/mL, 4.0 ng/mL<PSA<10.0 ng/mL and PSA ≥ 10.0 ng/mL groups were 25.00% (6/24),70.00% (7/10),66.67% (16/24),74.07% (20/27) and 94.83% (55/58) respectively, and bilateral comparison between groups revealed that difference in detection rate was statistically significant (P<0.01 or P<0.05). In terms of treatment,34 patients (27.64%) changed their pre-examination treatment regimen based on the results of 18F-PSMA-1007 PET/MR imaging. Conclusions: It reveals that prostate patients with detected recurrence or metastasis account for 25% of those with normal PSA level.The detection rate increases with the increase of PSA levels. It suggests that 18F-PSMA PET/MR can detect recurrence and metastasis in the early stage, which can effectively guide the formulation of treatment plans

    Polarization-Insensitive Metasurface for Harvesting Electromagnetic Energy with High Efficiency and Frequency Stability over Wide Range of Incidence Angles

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    In this paper, a polarization-insensitive metasurface, harvesting electromagnetic (EM) energy with high efficiency and frequency stability over a wide range of incidence angles, is proposed. The previously reported metasurfaces suffer from their maximum efficiencies shifting with the frequency when the incidence angle increases. By introducing a square-shaped metal via ring around the elements, the mutual coupling among adjacent cells is reduced so that the proposed metasurface can maintain maximum efficiency at the fixed operation frequency over a wide range of incidence angles. Furthermore, with one single harvesting via in the proper position for the connection of a harvesting load, the metasurface can collect EM energy effectively with both transverse electric (TE) and transverse magnetic (TM) polarizations in one single harvesting load. Compared with the reported metasurfaces, this proposed metasurface has a higher efficiency and fixed operation frequency within a wide incidence range. The energy distribution, harvesting efficiency, and surface current are simulated to investigate the operation mechanism of the proposed metasurface. The simulation results show that the maximum harvesting efficiency is 91% at 5.8 GHz for both TE and TM polarizations at the normal incidence. When the incident angle increases to 75°, the maximum efficiency is achieved at 5.79 GHz (0.19% shift), and the maximum efficiencies of TM and TE polarizations are 91% and 68%, respectively. A 5 × 5 array is fabricated and tested. The experimental results are in good agreement with the simulated ones

    Transcriptome Profiling to Identify Genes Involved in Mesosulfuron-Methyl Resistance in Alopecurus aequalis

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    Non-target-site resistance (NTSR) to herbicides is a worldwide concern for weed control. However, as the dominant NTSR mechanism in weeds, metabolic resistance is not yet well-characterized at the genetic level. For this study, we have identified a shortawn foxtail (Alopecurus aequalis Sobol.) population displaying both TSR and NTSR to mesosulfuron-methyl and fenoxaprop-P-ethyl, yet the molecular basis for this NTSR remains unclear. To investigate the mechanisms of metabolic resistance, an RNA-Seq transcriptome analysis was used to find candidate genes that may confer metabolic resistance to the herbicide mesosulfuron-methyl in this plant population. The RNA-Seq libraries generated 831,846,736 clean reads. The de novo transcriptome assembly yielded 95,479 unigenes (averaging 944 bp in length) that were assigned putative annotations. Among these, a total of 29,889 unigenes were assigned to 67 GO terms that contained three main categories, and 14,246 unigenes assigned to 32 predicted KEGG metabolic pathways. Global gene expression was measured using the reads generated from the untreated control (CK), water-only control (WCK), and mesosulfuron-methyl treatment (T) of R and susceptible (S). Contigs that showed expression differences between mesosulfuron-methyl-treated R and S biotypes, and between mesosulfuron-methyl-treated, water-treated and untreated R plants were selected for further quantitative real-time PCR (qRT-PCR) validation analyses. Seventeen contigs were consistently highly expressed in the resistant A. aequalis plants, including four cytochrome P450 monooxygenase (CytP450) genes, two glutathione S-transferase (GST) genes, two glucosyltransferase (GT) genes, two ATP-binding cassette (ABC) transporter genes, and seven additional contigs with functional annotations related to oxidation, hydrolysis, and plant stress physiology. These 17 contigs could serve as major candidate genes for contributing to metabolic mesosulfuron-methyl resistance; hence they deserve further functional study. This is the first large-scale transcriptome-sequencing study to identify NTSR genes in A. aequalis that uses the Illumina platform. This work demonstrates that NTSR is likely driven by the differences in the expression patterns of a set of genes. The assembled transcriptome data presented here provide a valuable resource for A. aequalis biology, and should facilitate the study of herbicide resistance at the molecular level in this and other weed species

    Neuroprotective Effect of Xueshuantong for Injection (Lyophilized) in Transient and Permanent Rat Cerebral Ischemia Model

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    Xueshuantong for Injection (Lyophilized) (XST), a Chinese Materia Medica standardized product extracted from Panax notoginseng (Burk.), is used extensively for the treatment of cerebrovascular diseases such as acutely cerebral infarction clinically in China. In the present study, we evaluated the acute and extended protective effects of XST in different rat cerebral ischemic model and explored its effect on peroxiredoxin (Prx) 6-toll-like receptor (TLR) 4 signaling pathway. We found that XST treatment for 3 days could significantly inhibit transient middle cerebral artery occlusion (MCAO) induced infarct volume and swelling percent and regulate the mRNA expression of interleukin-1β (IL-1β), IL-17, IL-23p19, tumor necrosis factor-α (TNFα), and inducible nitric oxide synthase (iNOS) in brain. Further study demonstrated that treatment with XST suppressed the protein expression of peroxiredoxin (Prx) 6-toll-like receptor (TLR) 4 and phosphorylation level of p38 and upregulated the phosphorylation level of STAT3. In permanent MCAO rats, XST could reduce the infarct volume and swelling percent. Moreover, our results revealed that XST treatment could increase the rats’ weight and improve a batch of functional outcomes. In conclusion, the present data suggested that XST could protect against ischemia injury in transient and permanent MCAO rats, which might be related to Prx6-TLR4 pathway
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