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In recent years, antibody-drug conjugate (ADC) technology, which uses monoclonal antibodies (mAbs) to specifically deliver effective cytotoxic payloads to tumor cells, has become a promising method of tumor targeted therapy. ADCs are a powerful class of biopharmaceuticals that link antibodies targeting specific antigens and small molecule drugs with potent cytotoxicity via a linker, thus enabling selective destruction of cancer cells while minimizing systemic toxicity. DXd is a topoisomerase I inhibitor that induces DNA damage leading to cell cycle arrest, making it an option for ADC payloads. The DXd-ADC technology, developed by Daiichi Sankyo, is a cutting-edge platform that produces a new generation of ADCs with improved therapeutic metrics and has shown significant therapeutic potential in various types of cancer. This review provides a comprehensive assessment of drugs developed with DXd-ADC technology, with a focus on mechanisms of action, pharmacokinetics studies, preclinical data, and clinical outcomes for DS-8201a, U3-1402, DS-1062a, DS-7300a, DS-6157a, and DS-6000a. By integrating existing data, we aim to provide valuable insights into the current therapeutic status and future prospects of these novel agents.
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Imunoconjugados , Humanos , Imunoconjugados/química , Imunoconjugados/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Animais , Estrutura Molecular , Inibidores da Topoisomerase I/química , Inibidores da Topoisomerase I/farmacologia , Anticorpos Monoclonais/químicaRESUMO
PURPOSE: To evaluate the utility of dual-energy CT (DECT) in differentiating non-hypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs) with negative carbohydrate antigen 19-9 (CA 19-9). METHODS: This retrospective study included 26 and 39 patients with pathologically confirmed non-hypervascular PNENs and CA 19-9-negative PDACs, respectively, who underwent contrast-enhanced DECT before treatment between June 2019 and December 2021. The clinical, conventional CT qualitative, conventional CT quantitative, and DECT quantitative parameters of the two groups were compared using univariate analysis and selected by least absolute shrinkage and selection operator regression (LASSO) analysis. Multivariate logistic regression analyses were performed to build qualitative, conventional CT quantitative, DECT quantitative, and comprehensive models. The areas under the receiver operating characteristic curve (AUCs) of the models were compared using DeLong's test. RESULTS: The AUCs of the DECT quantitative (based on normalized iodine concentrations [nICs] in the arterial and portal venous phases: 0.918; 95% confidence interval [CI] 0.852-0.985) and comprehensive (based on tumour location and nICs in the arterial and portal venous phases: 0.966; 95% CI 0.889-0.995) models were higher than those of the qualitative (based on tumour location: 0.782; 95% CI 0.665-0.899) and conventional CT quantitative (based on normalized conventional CT attenuation in the arterial phase: 0.665; 95% CI 0.533-0.797; all P < 0.05) models. The DECT quantitative and comprehensive models had comparable performances (P = 0.076). CONCLUSIONS: Higher nICs in the arterial and portal venous phases were associated with higher blood supply improving the identification of non-hypervascular PNENs.
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Carcinoma Ductal Pancreático , Tumores Neuroendócrinos , Neoplasias Pancreáticas , Humanos , Tomografia Computadorizada por Raios X , Estudos Retrospectivos , Meios de ContrasteRESUMO
To keep pace with the demands of semiconductor integration technology, a semiconductor device should offer a small footprint. Here, we demonstrate a compact electro-optic modulator by controlling the spatial distribution of carrier density in indium tin oxide (ITO). The proposed structure is mainly composed of a symmetrical metal electrode layer, calcium fluoride dielectric layer, and an ITO propagating layer. The carrier density on the surface of the ITO exhibits a periodical distribution when the voltage is applied on the electrode, which greatly enhances the interaction between the surface plasmon polaritons (SPPs) and the ITO. This structure can not only effectively improve the modulation depth of the modulator, but also can further reduce the device size. The numerical results indicate that when the length, width, and height of the device are 14 µm, 5 µm, and 8 µm, respectively, the modulation depth can reach 37.1 dB at a wavelength of 3.66 µm. The structure can realize a broadband modulation in theory only if we select a different period of the electrode corresponding to the propagating wavelength of SPPs because the modulator is based on the scattering effect principle. This structure could potentially have high applicability for optoelectronic integration, optical communications, and optical sensors in the future.
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BACKGROUND. The 2019 WHO classification of digestive system tumors separates neuroendocrine neoplasms (NENs) into neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs), which are considered to represent pathologically distinct entities warranting different management approaches. Dual-layer spectral-detector CT (DLCT) may aid their differentiation through specific material decomposition. OBJECTIVE. The purpose of this study was to assess the utility of quantitative metrics derived from DLCT for the differentiation of pancreatic NET and NEC. METHODS. This retrospective study included 104 patients (mean age, 51 ± 13 [SD] years; 52 women, 52 men) with pathologically confirmed NEN (89 NET, including 22 grade 1, 48 grade 2, and 19 grade 3; 15 NEC) who underwent multiphase DLCT within 15 days before biopsy or resection. Two radiologists independently placed ROIs to record tumor attenuation, iodine concentration (IC), and effective atomic number (Zeff) across phases and assessed qualitative features (composition, homogeneity, margins, calcifications, main pancreatic duct dilatation, vascular invasion, lymphadenopathy). Interobserver agreement was assessed. Mean and median values of both readers' measurements were obtained for quantitative measures; consensus was reached for qualitative features. NET and NEC were compared using multivariable regression analysis and ROC analysis. RESULTS. Interobserver agreement, expressed as intraclass correlation coefficients, ranged from 0.869 to 0.992 for quantitative metrics and, expressed as kappa coefficients, ranged from 0.723 to 0.816 for qualitative features. In multivariable analysis of qualitative and quantitative features, significant independent predictors of NEC (p < .05) were IC in the portal venous phase (median, 1.3 mg/mL for NEC vs 2.7 mg/mL for NET), Zeff in the portal venous phase (median, 8.1 vs 8.6), and attenuation in the portal venous phase (median, 78.2 vs 113.5 HU). AUC for predicting NEC was 0.897 for IC, 0.884 for Zeff, 0.921 for combination of IC and Zeff, and 0.855 for attenuation. Predicted probability based on a combination of IC and Zeff achieved sensitivity of 93.33% and specificity of 80.90% for predicting NEC. Significant independent predictors (p < .05) for differentiating grade 3 NET and NEC were IC (median, 2.0 vs 1.3 mg/mL; AUC = 0.789) and attenuation (mean, 90.3 vs 78.2 HU; AUC = 0.647), both measured in the portal venous phase. CONCLUSION. Incorporation of DLCT metrics improves differentiation of NET and NEC compared with conventional CT attenuation and qualitative features. CLINICAL IMPACT. DLCT may help select patients with pancreatic NENs for platinum-based chemotherapies.
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Carcinoma Neuroendócrino , Tumores Neuroendócrinos , Neoplasias Pancreáticas , Adulto , Benchmarking , Carcinoma Neuroendócrino/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Tumores Neuroendócrinos/diagnóstico por imagem , Tumores Neuroendócrinos/metabolismo , Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/metabolismo , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodosRESUMO
To keep pace with the demands in optical communications, electro-optic modulators should feature a high extinction ratio, offer a small footprint, and allow for practical detection. Herein, we demonstrate a compact plasmon modulator with a high extinction ratio where a compact modulation region composed of indium tin oxide (ITO) is embedded to the arms of the Mach-Zehnder (M-Z) interferometer. The modulator has a footprint of 20µm×12µm with a modulation region of 4µm×0.5µm. The numerical results show that the extinction ratio is 15.2 dB when the electron concentration of ITO is changed 4×1020cm-3. This type of modulator paves the way for future compact optoelectronic integration and has potential application in the fields of optical communication, photodetection, and sensing.
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Spontaneous fluctuations in MRI signals from gray matter (GM) in the brain are interpreted as originating from variations in neural activity, and their inter-regional correlations may be analyzed to reveal functional connectivity. However, most studies of intrinsic neuronal activity have ignored the spontaneous fluctuations that also arise in white matter (WM). In this work, we explore spontaneous fluctuations in resting state MRI signals in WM based on spatial independent component analyses (ICA), a data-driven approach that separates signals into independent sources without making specific modeling assumptions. ICA has become widely accepted as a valuable approach for identifying functional connectivity within cortex but has been rarely applied to derive equivalent structures within WM. Here, BOLD signal changes in WM of a group of subjects performing motor tasks were first detected using ICA, and a spatial component whose time course was consistent with the task was found, demonstrating the analysis is sensitive to evoked BOLD signals in WM. Secondly, multiple spatial components were derived by applying ICA to identify those voxels in WM whose MRI signals showed similar temporal behaviors in a resting state. These functionally-related structures are grossly symmetric and coincide with corresponding tracts identified from diffusion MRI. Finally, functional connectivity was quantified by calculating correlations between pairs of structures to explore the synchronicity of resting state BOLD signals across WM regions, and the experimental results revealed that there exist two distinct groupings of functional correlations in WM tracts at rest. Our study provides further insights into the nature of activation patterns, functional responses and connectivity in WM, and support previous suggestions that BOLD signals in WM show similarities with cortical activations and are characterized by distinct underlying structures in tasks and at rest.
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Mapeamento Encefálico , Substância Cinzenta/fisiologia , Vias Neurais/fisiologia , Substância Branca/fisiologia , Adulto , Mapeamento Encefálico/métodos , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Neurônios/fisiologia , Adulto JovemRESUMO
Sn-glycerol-3-phosphate acyltransferase (GPAT) catalyzes the acylation at sn-1 position of glycerol-3-phosphate to produce lysophosphatidic acid (LPA) in an acyl-CoA or acyl-ACP-dependent manner, which is the initial and rate-determining step of TAG biosynthetic pathway. Some GPATs have sn-2 transfer activity. Part members of the GPAT gene family have been cloned from different plant species. Based on their subcellular localizations, GPATs can be classified into three types, plastid GPATs, mitochondria GPATs and endoplasmic reticulum GPATs. GPATs exhibit diverse biochemical properties and are involved in synthesis of several lipids such as TAG, suberin, and cutin which play important roles in the growth and development of plants. This review summarized the current understanding of the chromosomal locus and gene structure of GPAT genes and the subcellular localization, sn-2 regiospecificity, substrates specialty, and functions of GPATs in plants.
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Glicerol-3-Fosfato O-Aciltransferase/metabolismo , Plantas/enzimologia , Plantas/metabolismo , Glicerol-3-Fosfato O-Aciltransferase/genética , Plantas/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
To solve the problems of environmental pollution and resource waste caused by the rapid development of cold chain logistics of fresh agricultural products and improve the competitiveness of logistics enterprises in the market, a performance evaluation method of cold chain logistics enterprises based on the combined empowerment-TOPSIS was proposed. Firstly, from the five dimensions of cold supply chain capacity, service quality, economic efficiency, informatization degree and development ability, a comprehensive evaluation system of logistics enterprises' sustainable development is constructed, which consists of 16 indicators, such as storage and preservation capacity, distribution accuracy, and equipment input rate. Then, G1 method and entropy weight method are used to calculate the subjective and objective weights of the evaluation indicators, and the combined weights are calculated with the objective of minimizing the deviation of the subjective and objective weighted attributes. Finally, the TOPSIS method is used to calculate the comprehensive evaluation indicators. The results show that the established performance evaluation model can effectively evaluate the performance of fresh agricultural products logistics enterprises and provide theoretical basis for enterprise logistics management.
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Multi-parameter control of light is a key functionality to modulate optical signals in photonic integrated circuits for various applications. However, the traditional optical modulators can only control one or two properties of light at the same time. Herein, we propose a hybrid structure which can modulate the amplitude, wavelength and phase of surface plasmon polaritons (SPPs) simultaneously to overcome these limitations. The numerical results show that when the Fermi level of graphene changes from 0.3 to 0.9 eV, the variation of optical transmission, wavelength and phase are 32.7 dB, 428 nm and 306°, respectively. The demonstrated structure triggers an approach for the realization of ultracompact modulation and has potential applications in the fields of optical switches, communications and photo-detection.
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PURPOSE: To explore the optimal energy level of dual-layer spectral detector computed tomography (DLCT) images of pancreatic neuroendocrine neoplasms (pNENs) and investigate the value in their detection. METHODS: This retrospective analysis included 134 pNEN patients with 136 lesions; they underwent contrast-enhanced DLCT scanning with histopathological confirmation of pNENs. Virtual monoenergetic images (VMI) of 40-100 keV, iodine concentration map (IC map), Z-effective atomic number map (Zeff map), and conventional images were analysed. The optimal energy level was obtained by comparing the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The lesion detection rates of DLCT and conventional images were compared. Subjective image analysis was performed by two readers who assessed the image quality and lesion conspicuity on a 5-point scale. RESULTS: The SNR of VMIs from 40 to 80 keV (arterial phase, P < 0.001; venous phase, P < 0.05) and CNR from 40 to 60 keV (arterial and venous phases, each P < 0.05) were higher than that of conventional images; VMI40keV showed the highest SNR and CNR. There was a good inter-reader agreement between the two reviewers (Kappa values > 0.61); the scores of Zeff and IC maps were higher than those of conventional images and VMI40keV (P < 0.05). The detection performance of DLCT images was better than conventional images. CONCLUSIONS: The VMI40keV demonstrated the best CNR and SNR of pNENs compared to other VMIs. Zeff and IC maps improve objective image quality and reader preference compared to conventional images. These findings could possess important clinical implications in formulating treatment strategies.
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Neoplasias Pancreáticas , Imagem Radiográfica a Partir de Emissão de Duplo Fóton , Humanos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Neoplasias Pancreáticas/diagnóstico por imagem , Razão Sinal-Ruído , Processamento de Imagem Assistida por Computador , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodosRESUMO
The manipulation of surface plasmon polaritons plays a pivotal role in plasmonic science and technology, however, the modulation efficiency of the traditional method suffers from the weak light-matter interaction. Herein, we propose a new method to overcome this obstacle by directly controlling the couple of photon and electron. In this paper, a hybrid graphene-dielectric- interdigital electrode structure is numerically and experimentally investigated. The plasmon is excited due to the confined carrier which is regulated by the potential wells. The frequency of plasmon can be tuned over a range of ~ 33 cm-1, and the obtained maximum extinction ratio is 8% via changing the confined area and the density of carrier. These findings may open up a new path to design the high efficiency all-optical modulator because the electrons can also be driven optically.
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Background: Patients with chronic pancreatitis often have irreversible pancreatic insufficiency before a clinical diagnosis. Pancreatic cancer is a fatal malignant tumor in the advanced stages. Patients having high risk of pancreatic diseases must be screened early to obtain better outcomes using new imaging modalities. Therefore, this study aimed to investigate the reproducibility of tomoelastography measurements for assessing pancreatic stiffness and fluidity and the variance among healthy volunteers. Methods: Forty-seven healthy volunteers were prospectively enrolled and underwent two tomoelastography examinations at a mean interval of 7 days. Two radiologists blindly and independently measured the pancreatic stiffness and fluidity at the first examination to determine the reproducibility between readers. One radiologist measured the adjacent pancreatic slice at the first examination to determine the reproducibility among slices and measured the pancreas at the second examination to determine short-term repeatability. The stiffness and fluidity of the pancreatic head, body, and tail were compared to determine anatomical differences. The pancreatic stiffness and fluidity were compared based on sex, age, and body mass index (BMI). Results: Bland-Altman analyses (all P > 0.05) and intraclass correlation coefficients (all >0.9) indicated near perfect reproducibility among readers, slices, and examinations at short intervals. Neither stiffness (P = 0.477) nor fluidity (P = 0.368) differed among the pancreatic anatomical regions. The mean pancreatic stiffness was 1.45 ± 0.09 m/s; the mean pancreatic fluidity was 0.83 ± 0.06 rad. Stiffness and fluidity did not differ by sex, age, or BMI. Conclusion: Tomoelastography is a promising and reproducible tool for assessing pancreatic stiffness and fluidity in healthy volunteers.
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Optical antennas are promising for optical trapping and particle manipulation, when converting light between localized energy and freely propagating radiation. In this paper, we proposed a numerical method for the transport of nanoparticles using the optical force field over a plasmonic Au antenna array. The plasmonic Au antenna array is designed to produce strong near-field hot spots when illuminated by a plane wave. The hot spots function as optical traps, separately addressable by their resonant wavelengths. By changing the traps sequentially, the nanoparticles can be handed off between adjacent traps. We also demonstrated a valid area in which the nanoparticles could be trapped and transferred stably by discussing the trapping potential that particles encountered. The simulated and calculated results showed that this method had promising applications in the field of biochemical diagnoses and high-accuracy optical manipulation.
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OBJECTIVE: We aimed to provide ideas for clinicians, especially radiologists, for the diagnosis of multiple endocrine neoplasia (MEN) syndromes. BACKGROUND: MEN syndromes include MEN1, MEN2, and MEN4 and usually involve 2 or more endocrine tumors. The MEN syndromes are a group of euchromatic dominant genetic diseases, and the main genes involved include MEN1 (MEN1), RET (MEN2), and CDKN1B (MEN4). METHODS: In this article, involving 8 cases (4 cases of MEN1, 2 cases of MEN2A, 1 case of MEN2B, 1 case of MEN4) from our center, we introduced the disease spectrum, clinical manifestations (especially imaging findings), and related genes involved in each type of MEN syndromes. We also discussed the differential diagnosis between MEN and sporadic tumors and emphasized that MEN should be screened and the relevant required examinations. CONCLUSIONS: Considering that MEN syndromes involve multiple endocrine gland tumors and nonendocrine organ diseases, it is very important to identify potential patients early and perform multiple examinations on them, including biochemical and multitype, and multisite imaging examinations according to the disease spectrum of each type. Considering that this is a group of genetic diseases, both interviewing patients about their family history and genetic testing are also very important. Only in this way can a comprehensive and accurate diagnosis be made, enabling patients to receive appropriate treatment and improve their prognosis.
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Cesium lead-halide (CsPbX3; X = Cl, Br, I) perovskite microstructure arrays have become the basis for laser array applications, due to their outstanding spectral coherence, low threshold, and wideband tunability. Furthermore, the common fabrication methods for these arrays have the limitation to achieve both tailored design and high resolution simultaneously. Herein, we report a high-precision, template-assisted, wet etching (TAWE) method for the preparation of perovskite microstructure arrays. This method possesses the advantages of flexible design, controllable size, and ultrahigh accuracy (the resolution can reach 1 µm or higher). A 20 × 20 inverted pyramid array with a diameter of 3 µm and a period of 4 µm was fabricated using this method. CsPbBr3 perovskite quantum dots fabricated by means of hot injection were filled into the inverted pyramid array via spin-coating and pumped using a laser with a wavelength of 400 nm. The lasing characteristics of the array were then measured and analyzed; the threshold was measured to be 37.6 µJ cm-2, and the full width at half maximum of the amplified spontaneous emission spectrum was found to be about 4.7 nm. These results demonstrate that perovskite microstructure arrays prepared via this method have potential applications in laser arrays.
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An environmentally friendly approach for the comprehensive utilization of shrimp shell waste was reported. Instant catapult steam explosion (ICSE) was employed for shrimp shell waste pretreatment. After ICSE, lower crystallinity and greater surface areas of shrimp shells were achieved, which significantly enhanced the extraction of chitin. Compared to the traditional method, weaker organic acid (HCOOH) and much lower dosages of KOH (90% molar less) were used, and chitin with a high demineralization rate (98.2%) and deproteinization rate (97.7%) was obtained. The wastewater was neutralized by simply intermixing, and it was recycled as a potential plant fertilizer because it contained more oligopeptides, calcium, and potassium, but it was less salty and therefore non-toxic to plants. The whole process produced less solid waste and no waste water. The obtained chitin also showed a low degree of acetylation (50.5%), which demonstrates the potential for environmentally friendly preparation of chitosan in dilute alkali through ICSE.
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Large scale cesium lead-halide (CsPbX3, X = Cl, Br, and I) perovskite films have become the basis of laser applications. Common fabrication methods such as spin-coating and thermal evaporation have a trade-off between high quality and low cost. Herein, we reported a facile method for preparing a large area homogeneous perovskite CsPbBr3 film via a multiple centrifugal deposition and solvent annealing (MCDSA) method. This method is superior because it can control the thickness (180 nm to 880 nm) of the film, ensure the film is crack and pinhole free, has a large area (2.5 cm × 2.5 cm), and has a low surface roughness (a root mean square of 32 nm). Multiple times of centrifugation and solvent annealing in the MCDSA method are key to improving the quality of the film as well as the laser performance. With increased centrifugation cycles from one to four, the thickness of the film increases from 180 nm to 880 nm, leading to a decrease in the laser threshold from 18.1 µJ cm-2 to 14.2 µJ cm-2 and an increase in the gain coefficient from 78.5 cm-1 to 112.7 cm-1. When solvent annealing is employed, the gain coefficient is further increased to 122.7 cm-1.
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The forkhead protein (FoxO) family plays a crucial role in regulating oxidative stress, cell proliferation, and apoptosis. FoxO6, a member of the FoxO family, helps regulate oxidative stress in gastric cancer and hepatocellular carcinoma. However, it is unclear whether FoxO6 participates in the protective effect of isoflurane preconditioning in liver injury caused by oxidative stress in ischemia. In this study, we explored the role and mechanism of FoxO6 in the protective effect of isoflurane preconditioning during hepatocyte injury caused by oxygen-glucose deprivation (OGD). Cells from the human fetal hepatocyte (LO2) line were incubated with 0%, 1%, 2%, 2.5%, 3%, 3.5%, 4%, or 5% isoflurane for 3 h and then exposed to OGD. Data showed that 3% isoflurane preconditioning inhibited FoxO6 expression, caspase-3 activity, and reactive oxygen species production and promoted cell viability. FoxO6 overexpression abolished the effects of 3% isoflurane preconditioning on caspase-3 activity, reactive oxygen species production, and cell viability in these cells. Moreover, FoxO6 regulated nuclear factor erythroid 2-related factor (Nrf2) expression via c-Myc after 3% isoflurane preconditioning and OGD exposure. Thus, isoflurane preconditioning prevented OGD-induced injury in LO2 cells by modulating FoxO6, c-Myc, and Nrf2 signaling.
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Fatores de Transcrição Forkhead/genética , Isoflurano/farmacologia , Fator 2 Relacionado a NF-E2/genética , Neurônios/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/genética , Apoptose/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Hepatócitos/efeitos dos fármacos , Humanos , Precondicionamento Isquêmico/métodos , Fígado/efeitos dos fármacos , Fígado/lesões , Fígado/metabolismo , Fígado/patologia , Neurônios/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
In this study, instant catapult steam explosion (ICSE) was employed for chitin treatment, and the effect of ICSE on the chitin structure was systematically investigated by using a series of analytical techniques including scanning electron microscopy, X-ray diffraction and Brunauer-Emmett-Teller analysis. Due to the powerful seepage force of the steam during ICSE, the crystallinity index of chitin decreased 10.2% in the (1 1 0) plane and 13.3% in the (0 2 0) plane. Significantly larger surface areas (up to 2.5 times greater, 12.69 m²/g at 1.6 MPa) with more and larger pores (up to a 3.5 times larger pore volume, 0.0333 cm³/g at 2.0 MPa) were achieved after ICSE, and numerous lacerated-like pore shapes were observed on the porous surface of chitin. Importantly, the molecular structure of chitin remained intact with no substantial damage to chitin's molecular weight, thermostability and acetylation (â¼70%), which ensures the possibility and diversity of further chitin derivatization.
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Using selected sepiolite (SEP) and biochar (BC) as contrasts, we investigated the effects of a new cross-linked modified chitin (CC) on the bioavailability of Pb and Cd in soils, the yield of rice, and the absorption and accumulation of Pb and Cd in different parts of rice plants in a field environment. We hope this study provides the basis for the application of this material to improve soil fertility, and a direction for further soil improvement studies. A field experiment was carried out in 2015-2016 on selected Pb- and Cd-contaminated rice fields in Linghai, Liaoning. The changes in soil pH and available Pb and Cd in the soil were analyzed after the rice was harvested(October 2016). The effects of different treatments on the growth traits and yield of rice, the absorption of Pb and Cd by rice roots, stems and leaves, and grains were compared. The results showed that adding 167-333 kg·hm-2 CC could increase the soil pH value by 0.36-0.45 units, decreasing the contents of available Pb and Cd in the soil by 46.39%-64.01% and 29.73%-43.24% respectively (P<0.05). This treatment significantly reduced the Pb and Cd contents in all parts of rice (P<0.05) compared to conventional fertilization; Pb and Cd contents in different parts of rice were significantly reduced (P<0.05) by 16.09%-38.14% and 21.22%-31.38% in the root, 19.17%-46.92% and 25.66%-45.34% in the stem and leaf, and 29.47%-58.25% and 44.75%-64.02% in the grain, respectively. The treatment of adding 333 kg·hm-2 CC (CC-2) reduced the contents of Pb and Cd in rice grains to 0.2041±0.011 mg·kg-1 and 0.1922±0.021 mg·kg-1, respectively, which were lower than or close to the limit values of Pb and Cd in rice (0.20 mg·kg-1) as per GB 2762-2005. Compared to conventional fertilization, SEP treatment, and BC treatment, without adding any amendments, the yield per mu of rice under CC treatment increased by 33.6-47, 27.6-44, and 8.67-34.77 kg, respectively. The effect of CC-2 treatment on yield was the most obvious; the yield of rice per mu increased by 47 kg, and the yield increase rate was 8.59%. The ability of CC to repair soil contaminated by Pb and Cd and to reduce the contents of Pb and Cd in rice was not weaker than that of SEP and BC. The CC treatment also controlled the migration and redistribution of Pb and Cd in soil-rice systems, and significantly increased the yield of rice. It has good potential to ensure the safe production of rice.