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1.
Theranostics ; 10(4): 1758-1776, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32042335

RESUMO

Background and Aim: DOT1L regulates various genes involved in cancer onset and progression by catalyzing H3K79 methylation, but how DOT1L activity itself is regulated is unclear. Here, we aimed to identify specific DOT1L post-translational modifications that might regulate DOT1L activity and thus impact on colorectal cancer (CRC) progression. Methods: We conducted affinity purification and mass spectrometry to explore DOT1L post-translational modifications. We then established transwell migration and invasion assays to specifically investigate the role of DOT1L(K358) acetylation on CRC cellular behavior in vitro and a bioluminescence imaging approach to determine the role of DOT1L(K358) acetylation in CRC metastasis in vivo. We performed chromatin immunoprecipitation to identify DOT1L acetylation-controlled target genes. Finally, we used immunohistochemical staining of human tissue arrays to examine the relevance of DOT1L(K358) acetylation in CRC progression and metastasis and the correlation between DOT1L acetylation and CBP. Results: We found that CBP mediates DOT1L K358 acetylation in human colon cancer cells and positively correlates with CRC stages. Mechanistically, DOT1L acetylation confers DOT1L stability by preventing the binding of RNF8 to DOT1L and subsequent proteasomal degradation, but does not affect its enzyme activity. Once stabilized, DOT1L can catalyze the H3K79 methylation of genes involved in epithelial-mesenchymal transition, including SNAIL and ZEB1. An acetylation mimic DOT1L mutant (Q358) could induce a cancer-like phenotype in vitro, characterized by metastasis and invasion. Finally, DOT1L(K358) acetylation correlated with CRC progression and a poor survival rate as well as with high CBP expression. Conclusions: DOT1L acetylation by CBP drives CRC progression and metastasis. Targeting DOT1L deacetylation signaling is a potential therapeutic strategy for DOT1L-driven cancers.

2.
BMC Musculoskelet Disord ; 21(1): 98, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32054465

RESUMO

BACKGROUND: Whether or not, prophylactic neurosurgical interventions of split cord malformation (SCM) before undertaking corrective surgery was the focus of debate. The present study was performed to evaluate the safety and efficacy of posterior-only surgical correction with heavy halo-femoral traction for the treatment of rigid congenital scoliosis (RCS) associated with SCM. METHODS: From 2011 to 2017, 24 patients suffered from RCS associated with SCM underwent posterior-only surgical correction with heavy halo-femoral traction. The apex of the deformity was lumbar (n = 9), thoracic (n = 11), and thoracolumbar (n = 4). There were 13 cases of failure of segmentation; 4 cases of failure of formation and 7 cases of mixed defects. Based on SCM classification, there were 14 patients with SCM type 1 and 10 patients with SCM type 2. The Scoliosis Research Society (SRS)-22 and modified Japanese Orthopaedic Association (mJOA) scores were assessed preoperatively and at the final follow up. RESULTS: The mean duration of surgery was 327.08 ± 43.99 min and the mean blood loss was 1303.33 ± 526.86 ml. The mean follow-up period was 20.75 ± 8.29 months. The preoperative mean coronal Cobb angle was 80.38° ± 13.55°; on the bending radiograph of the convex side, the mean Cobb angle was 68.91° ± 15.48°; the mean flexibility was 15.04% ± 7.11%. After heavy halo-femoral traction, the mean coronal Cobb angle was reduced to 56.89° ± 13.39°. After posterior-only surgical correction, postoperative mean coronal Cobb angle was further reduced to 32.54° ±11.33°. The postoperative mean correction rate was 60.51% ± 7.79%. At the final follow up, the corrective loss rate of Cobb angle was only 3.17%. The SRS-22 total score improved at the final follow-up evaluation compared with the preoperative SRS-22 total score. The spinal cord function was stable and there were no new neurological symptoms after correction. There were no significant differences between final follow-up and preoperative mJOA total scores. CONCLUSIONS: Without prophylactic neurosurgical intervention and spine-shortening osteotomy, posterior-only surgical correction with heavy halo-femoral traction could be safe and effective for the treatment of RCS associated with SCM.

3.
Mol Biol Evol ; 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32027372

RESUMO

Pikas are widely distributed in the Northern Hemisphere and are highly adapted to cold and alpine environments. They are one of the most complex and problematic groups in mammalian systematics, and the origin and evolutionary history of extant pikas remain controversial. In this study, we sequenced the whole coding sequences of 105 pika samples (29 named species, 1 putative new species) and obtained DNA data for more than 10000 genes. Our phylogenomic analyses recognized four subgenera of extant pikas: Alienauroa, Conothoa, Ochotona and Pika. The interrelationships between the four subgenera were strongly resolved as (Conothoa, (Alienauroa, (Ochotona, Pika))), with the mountain group Conothoa being the sister group of all other pikas. Our divergence time and phylogeographic analyses indicated that the last common ancestor of extant pikas first occurred on in the middle Miocene, approximately 14 million years ago. The emergence of opportunities related to the climate, food supply and spreading paths in concert promoted the dispersal of pikas from the Qinghai-Tibetan Plateau (QTP) to other parts of Eurasia and North America. We found that the genes that were positively selected in the early evolution of pikas were most concentrated in functional categories related to cold tolerance. These results suggest that the QTP may have served as a training ground for cold tolerance in early pikas, which gives pikas a great advantage when the climate continued to cool after the middle Miocene. Our study highlights the importance of the QTP as a center of origin for many cold-adapted animals.

4.
Cell Mol Life Sci ; 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32008086

RESUMO

BACKGROUND: Small bowel vascular malformation disease (SBVM) is the most common cause of obscure gastrointestinal bleeding (OGIB). Several studies suggested that EGFL6 was able to promote the growth of tumor endothelial cells by forming tumor vessels. To date, it remains unclear how EGFL6 promotes pathological angiogenesis in SBVM and whether EGFL6 is a target of thalidomide. METHODS: We took advantage of SBVM plasma and tissue samples and compared the expression of EGFL6 between SBVM patients and healthy people via ELISA and Immunohistochemistry. We elucidated the underlying function of EGFL6 in SBVM in vitro and by generating a zebrafish model that overexpresses EGFL6, The cycloheximide (CHX)-chase experiment and CoIP assays were conducted to demonstrate that thalidomide can promote the degradation of EGFL6 by targeting CRBN. RESULTS: The analysis of SBVM plasma and tissue samples revealed that EGFL6 was overexpressed in the patients compared to healthy people. Using in vitro and in vivo assays, we demonstrated that an EMT pathway triggered by the EGFL6/PAX6 axis is involved in the pathogenesis of SBVM. Furthermore, through in vitro and in vivo assays, we elucidated that thalidomide can function as anti-angiogenesis medicine through the regulation of EGFL6 in a proteasome-dependent manner. Finally, we found that CRBN can mediate the effect of thalidomide on EGFL6 expression and that the CRBN protein interacts with EGFL6 via a Lon N-terminal peptide. CONCLUSION: Our findings revealed a key role for EGFL6 in SBVM pathogenesis and provided a mechanism explaining why thalidomide can cure small bowel bleeding resulting from SBVM.

5.
Medicine (Baltimore) ; 99(4): e18951, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31977912

RESUMO

RATIONALE: An amniotic fluid embolism (AFE) is a rare, lethal syndrome that is commonly associated with disseminated intravascular coagulation (DIC). Anticoagulation therapy is the most important strategy to inhibit excessive activation of the coagulation cascade in patients with AFE and DIC. At present, treatment of AFE with rivaroxaban has not been reported. PATIENT CONCERNS: We report a 37-year-old woman (gravida 2, para 1) at 39 weeks' gestation with irregular contractions of the uterus was admitted to the obstetrical department. Ten minutes after the spontaneous rupture of the membranes, the patient complained of dyspnea and dysphoria and exhibited cyanosis of her lips. The patient's blood pressure decreased and heart rate increased rapidly, and 2100 mL of unclotted blood flowed from her vagina within 1 hour. Her platelet count dropped to 21 × 10/L, and the results from routine coagulation tests, and D-dimer and fibrin degradation product tests were obviously abnormal. DIAGNOSES: According to the current research consensus, AFE with DIC should be considered immediately when sudden cardiovascular collapse occurs around the time of labor and delivery, followed by the development of coagulopathy and hemorrhage. INTERVENTIONS: In addition, the variety of supportive treatments, rivaroxaban was used in anticoagulant therapy. OUTCOMES: At follow-up 30 and 60 days, there were no complaints of discomfort or abnormal laboratory assays. The patient recovered completely. LESSONS: This case highlights that rivaroxaban, as a direct inhibitor of activated factor Xa, demonstrates a good therapeutic efficacy for treating AFE with DIC.


Assuntos
Coagulação Intravascular Disseminada/tratamento farmacológico , Embolia Amniótica/tratamento farmacológico , Inibidores do Fator Xa/administração & dosagem , Rivaroxabana/administração & dosagem , Adulto , Transfusão de Eritrócitos , Feminino , Humanos , Gravidez , Resultado do Tratamento
6.
Nucleic Acids Res ; 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31970415

RESUMO

Genomic instability is an underlying hallmark of cancer and is closely associated with defects in DNA damage repair (DDR). Chromatin relaxation is a prerequisite for DDR, but how chromatin accessibility is regulated remains elusive. Here we report that the histone deacetylase SIRT6 coordinates with the chromatin remodeler CHD4 to promote chromatin relaxation in response to DNA damage. Upon DNA damage, SIRT6 rapidly translocates to DNA damage sites, where it interacts with and recruits CHD4. Once at the damage sites, CHD4 displaces heterochromatin protein 1 (HP1) from histone H3 lysine 9 trimethylation (H3K9me3). Notably, loss of SIRT6 or CHD4 leads to impaired chromatin relaxation and disrupted DNA repair protein recruitment. These molecular changes, in-turn, lead to defective homologous recombination (HR) and cancer cell hypersensitivity to DNA damaging agents. Furthermore, we show that SIRT6-mediated CHD4 recruitment has a specific role in DDR within compacted chromatin by HR in G2 phase, which is an ataxia telangiectasia mutated (ATM)-dependent process. Taken together, our results identify a novel function for SIRT6 in recruiting CHD4 onto DNA double-strand breaks. This newly identified novel molecular mechanism involves CHD4-dependent chromatin relaxation and competitive release of HP1 from H3K9me3 within the damaged chromatin, which are both essential for accurate HR.

7.
Nat Chem ; 12(2): 137-144, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31792389

RESUMO

Inorganic semiconductor nanocrystals interfaced with spin-triplet exciton-accepting organic molecules have emerged as promising materials for converting incoherent long-wavelength light into the visible range. However, these materials to date have made exclusive use of nanocrystals containing toxic elements, precluding their use in biological or environmentally sensitive applications. Here, we address this challenge by chemically functionalizing non-toxic silicon nanocrystals with triplet-accepting anthracene ligands. Photoexciting these structures drives spin-triplet exciton transfer from silicon to anthracene through a single 15 ns Dexter energy transfer step with a nearly 50% yield. When paired with 9,10-diphenylanthracene emitters, these particles readily upconvert 488-640 nm photons to 425 nm violet light with efficiencies as high as 7 ± 0.9% and can be readily incorporated into aqueous micelles for biological use. Our demonstration of spin-triplet exciton transfer from silicon to molecular triplet acceptors can critically enable new technologies for solar energy conversion, quantum information and near-infrared driven photocatalysis.

8.
Biomed Tech (Berl) ; 65(1): 73-86, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31525154

RESUMO

Due to velopharyngeal incompetence, airflow overflows from the oral cavity to the nasal cavity, which results in hypernasality. Hypernasality greatly reduces speech intelligibility and affects the daily communication of patients with cleft palate. Accurate assessment of hypernasality grades can provide assisted diagnosis for speech-language pathologists (SLPs) in clinical settings. Utilizing a support vector machine (SVM), this paper classifies speech recordings into four grades (normal, mild, moderate and severe hypernasality) based on vocal tract characteristics. Linear prediction (LP) analysis is widely used to model the vocal tract. Glottal source information may be included in the LP-based spectrum. The stabilized weighted linear prediction (SWLP) method, which imposes the temporal weights on the closed-phase interval of the glottal cycle, is a more robust approach for modeling the vocal tract. The extended weighted linear prediction (XLP) method weights each lagged speech signal separately, which achieves a finer time scale on the spectral envelope than the SWLP method. Tested speech recordings were collected from 60 subjects with cleft palate and 20 control subjects, and included a total of 4640 Mandarin syllables. The experimental results showed that the spectral envelope of normal speech decreases faster than that of hypernasal speech in the high-frequency part. The experimental results also indicate that the SWLP- and XLP-based methods have smaller correlation coefficients between normal and hypernasal speech than the LP method. Thus, the SWLP and XLP methods have better ability to distinguish hypernasal from normal speech than the LP method. The classification accuracies of the four hypernasality grades using the SWLP and XLP methods range from 83.86% to 97.47%. The selection of the model order and the size of the weight function are also discussed in this paper.

9.
Cancer Lett ; 472: 119-131, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31866466

RESUMO

Although trastuzumab has greatly improved the outcome of HER2-positive breast cancer, the emergence of resistance hampers its clinical benefits. Trastuzumab resistance is a multi-factorial consequence predominantly due to presence of cancer stem-like cells (CSCs). AZD1775, a potent anti-cancer agent targeting WEE1 kinase to drive tumor cells with DNA damage to premature mitosis, has previously shown high efficacies when targeting different cancers with a well-tolerated cytotoxic profile, but has not been evaluated in trastuzumab-resistant (TrR) breast cancer. We sought to investigate the effect of AZD1775 on cancer stem-like cell (CSC) properties, apoptosis, cell cycle regulation in TrR breast cancer. Our study for the first time demonstrated that AZD1775 induces apoptosis and arrests TrR cells at G2/M phase. More importantly, AZD1775 effectively targeted CSC properties by suppressing MUC1 expression levels. AZD1775 administration also induced apoptosis in our in-house patient-derived tumor cell line at passage 0, implying its significant clinical relevance. These findings highlight the potential clinical application of AZD1775 in overcoming trastuzumab resistance in breast cancer.

10.
Oncogene ; 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31831835

RESUMO

The original version of this Article omitted the following from the Acknowledgements: Professor Stebbing sits on SABs for Celltrion, Singapore Biotech, Vor Biopharma, TLC Biopharmaceuticals and Benevolent AI, has consulted with Lansdowne partners, Vitruvian and Social Impact Capital and Chairs the Board of Directors for BB Biotech Healthcare Trust and Xerion Healthcare. This has now been corrected in both the PDF and HTML versions of the Article.

11.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 50(6): 827-834, 2019 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-31880113

RESUMO

OBJECTIVE: To detect the effects and mechanism of asprosin (Asp) and spartin on the injury of mice cardiac microvascular endothelial cells (CMECs) induced by high glucose. METHODS: The cultured CMECs were divided into 2 groups, one group is normal group (5.5 mmol/L glucose in the medium) and another is HG group (30 mmol/L glucose in the medium). Real-time PCR (qRT-PCR) and Western blot were respectively used to detect the mRNA level of spastic paraplegia 20 (SPG20) and protein expression of spartin in CMECs. Upregulation or downregulation of the expression of spartin was achieved via transfection with adenovirus (Ad) or small interfering RNA (siRNA) respectively. CMECs with downregulation of spartin expression were firstly treated with anti-oxidant N-acetylcysteine (NAC) or Asp respectively for 48 h, and then were interfered with 30 mmol/L glucose for 24 h afterward. The apoptosis of cell was detected by flow cytometry. Nitric oxide (NO) production was detected by NO probe and ELISA kit. The intracellular reactive oxygen species (ROS) levels were tested by DHE staining and ELISA kit. Type 2 diabetic model mice were established and then divided into T2DM group and T2DM+Asp group. After the model mice were established successfully (random blood glucose was more than 16.7 mmol/L), Asp (1 µg/g) was intraperitoneally injected once a day. After 2 weeks, mice echocardiography was performed to test cardiac diastolic function. The integrity of the microvascular endothelium was observed by scanning electron microscopy. RESULTS: Compared with the normal group, the mRNA level of SPG20 and protein expression of spartin in mice CMECs of HG group were significantly reduced (P < 0.05). Under the condition of high glucose, Ad transfection induced significant decrease of the intracellular ROS level and the apoptosis level of the CMECs (P < 0.05), while NO increased after Ad transfection. In contrast, siRNA intervention resulted in opposite effect. In addition, the antioxidant NAC partly reversed the above changes caused by downregulating spartin. Asp upregulated the level of SPG20 mRNA and spartin protein expression in CMECs, reduced ROS production, reduced apoptosis and increased NO production. However, intervention effects of Asp, such as decreasing of ROS production, inhibiting apoptosis of CMECs and increasing of NO production, were partly reversed in spartin downregulated cells. In vivo, we found that Asp can improve cardiac function and increase the integrity and smoothness of cardiac microvascular endothelium in type 2 diabetic mice. CONCLUSION: Asp can inhibit oxidative stress in mice CMECs through upregulating spartin signaling pathway, thereby alleviating the damage of microvascular endothelium in diabetic heart.


Assuntos
Diabetes Mellitus Experimental , Células Endoteliais , Animais , Apoptose , Células Cultivadas , Camundongos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio
12.
Phys Rev E ; 100(5-1): 052312, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31870001

RESUMO

Recent years have witnessed a growing interest in using machine learning to predict and identify critical dynamical phase transitions in physical systems (e.g., many-body quantum systems). The underlying lattice structures in these applications are generally regular. While machine learning has been adopted to complex networks, most existing works concern about the structural properties. To use machine learning to detect phase transitions and accurately identify the critical transition points associated with dynamical processes on complex networks thus stands out as an open and significant problem. Here we develop a framework combining supervised and unsupervised learning, incorporating proper sampling of training data set. In particular, using epidemic spreading dynamics on complex networks as a paradigmatic setting, we start from supervised learning alone and identify situations that degrade the performance. To overcome the difficulties leads to the idea of exploiting confusion scheme, effectively a combination of supervised and unsupervised learning. We demonstrate that the scheme performs well for identifying phase transitions associated with spreading dynamics on homogeneous networks, but the performance deteriorates for heterogeneous networks. To strive to meet this challenge leads to the realization that sampling the training data set is necessary for heterogeneous networks, and we test two sampling methods: one based on the hub nodes together with their neighbors and another based on k-core of the network. The end result is a general comprehensive machine learning framework for detecting phase transition and accurately identifying the critical transition point, which is robust, computationally efficient, and universally applicable to complex networks of arbitrary size and topology. Extensive tests using synthetic and empirical networks verify the virtues of the articulated framework, opening the door to exploiting machine learning for understanding, detection, prediction, and control of complex dynamical systems in general.

13.
Opt Express ; 27(25): 36680-36690, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31873441

RESUMO

We propose and demonstrate a single-step digital back propagation (DBP) algorithm for metro and regional transmissions with high order modulation formats. Based on subcarrier-multiplexing (SCM)-DBP, two modifications are made to improve performance and reduce complexity for the targeted link scenarios. First, an infinite impulse response (IIR) filter is adopted in self-subcarrier nonlinear compensation. Second, the second stage chromatic dispersion (CD) compensation is incorporated into an existing adaptive filter. Through experiment, we demonstrate the performance of the proposed scheme, denoted as M-SCM-DBP, for single channel 34.94-GBd SCM PDM-32QAM transmission. With 86.3% complexity reduction compared with the low-pass filter assisted DBP, the proposed M-SCM-DBP achieves 0.6-dB Q2 improvement for SCM-PDM-32QAM transmission over 960-km standard single mode fiber (SSMF). The reach extension of 36% to 1220-km is achieved with only 30.5 complex multiplications per sample, in comparison with the linear compensation scheme. Since the adaptive filter is used to simultaneously compensate 50% CD and other linear impairments, we also investigate the required number of filter taps and its polarization tracking ability.

14.
Appl Opt ; 58(34): G6-G10, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31873479

RESUMO

In this research, a novel optical multiple-image encryption method based on angular-multiplexing holography, quick response (QR) code, and spiral phase keys is proposed. With this method, images are transformed into QR codes and subsequently encrypted into a series of encrypted holograms using an angular-multiplexing technique. The encrypted holograms can only be decrypted when the hologram is illuminated with a duplicate of the reference beam and correct fingerprint and spiral phase plate (SPP) keys. The multiplexing performance and key sensitivity of fingerprint and SPP order were both analyzed, showing the high strength of the security of our proposed method.

15.
Opt Express ; 27(26): 37286-37297, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31878511

RESUMO

Co-frequency and co-time full duplex (CCFD) technique has the potential to further improve the capacity of the fifth-generation (5G) system. However, in a CCFD-based transceiver, the self-interference-cancellation (SIC) module is essential because the transmitted signal is also captured by the receiving antenna. In this paper, an optimized SIC technique is proposed based on a dual-parallel Mach-Zehnder modulator (DP-MZM). In addition to the multipath effect between the transmitting and receiving antennas, the nonlinear distortion induced by the used optical and electrical components is considered and analyzed for the first time. In this scheme, one of the children MZMs is biased at 90°. The bias points of the other child MZM and the parent MZM are swept for SIC optimization. Compared to the traditional SIC scheme using DP-MZM, the power of the received signal is increased by 6 dB and the robustness to the bias point drift is improved. In our experiment, over 35 dB cancellation ratio is achieved for 200 MHz filtered orthogonal frequency division multiplexing (F-OFDM) interference signal with carrier frequency from 2.5 GHz to 6 GHz. To mitigate the influence of multipath effect and nonlinear distortion, the recursive least squared (RLS) linear equalizer and the RLS Volterra equalizer are designed and compared. Finally, 42 dB cancellation ratio is achieved for 200 MHz F-OFDM signal with carrier frequency of 4.5 GHz in the presence of nonlinear distortion and emulated multipath effect.

16.
Opt Express ; 27(26): 37614-37621, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31878540

RESUMO

We report the peak-power-clamping (PPC) effect in a polarization-maintaining (PM) Q-switched mode locking fiber laser. The laser cavity with a compact and stable all-PM fiber configuration can clearly demonstrate three different output states including normal Q-switching, PPC Q-switching, and PPC Q-switched mode-locking (QML) with the increasing pump power. To the best of our knowledge, it is the first time that PPC effect is successfully obtained and analyzed from the Q-switching to QML. This research extends the theory of PPC in pulsed lasers and reveals the potential to achieve ultra-high pulse energy.

17.
Huan Jing Ke Xue ; 40(7): 3331-3338, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854735

RESUMO

The remediation of cadmium (Cd) contaminated paddy soils has become an important issue in the field of remediation of agricultural soils contaminated by heavy metals. The iron (Fe) redox cycle (referring to the fluctuation of iron between the ferrous (Ⅱ) and ferric (Ⅲ) oxidation states) exhibits a unique role in the transportation of Cd in the soil-rice system. The exploration of practical remediation strategies for Cd from the perspective of the Fe redox cycle is expected to obtain some state-of-the-art technologies and products to reduce Cd accumulation in rice grains. In this study, an amendment was selected and a field experiment was carried out to investigate the effects of this amendment on Cd transportation from the rhizosphere soil to the Fe plaque, and further to different rice tissues at four different growth stages, and to highlight some possible mechanisms by which the Fe redox cycle controls Cd availability in rice paddy fields. The results showed that the amendment induced the formation of Fe sulfides, which co-precipitated with Cd, reducing the NH4Ac-extractable Cd content in rhizosphere soils at the tillering, jointing, and filling stages; the oxidation of Fe sulfides increased the NH4Ac-extractable Cd content in the rhizosphere soil at the maturing stage; the formation of Fe sulfides in rhizosphere soils impeded the migration of Fe(Ⅱ) from the rhizosphere soil to the root surface, decreasing the content of DCB-extractable Fe and Cd in Fe plaques at the tillering and filling stages; the amendment inhibited Cd transportation from the roots to other tissues, increasing the proportion of Cd in the roots at the jointing, filling, and maturing stages, but decreasing the proportion in the straws at the jointing, filling, and maturing stages, and in the rice grain at the maturing stage. These findings provide a theoretical basis for the exploration and application of the amendment, and have significance in the field of remediation of Cd-contaminated paddy soils.


Assuntos
Cádmio/química , Ferro/química , Oryza , Rizosfera , Poluentes do Solo/química
18.
Chaos ; 29(11): 113106, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31779342

RESUMO

Deep learning has taken part in the competition since not long ago to learn and identify phase transitions in physical systems such as many-body quantum systems, whose underlying lattice structures are generally regular as they are in Euclidean space. Real networks have complex structural features that play a significant role in dynamics in them, and thus the structural and dynamical information of complex networks cannot be directly learned by existing neural network models. Here, we propose a novel and effective framework to learn the epidemic threshold in complex networks by combining the structural and dynamical information into the learning procedure. Considering the strong performance of learning in Euclidean space, the Convolutional Neural Network (CNN) is used, and, with the help of "confusion scheme," we can identify precisely the outbreak threshold of epidemic dynamics. To represent the high-dimensional network data set in Euclidean space for CNN, we reduce the dimensionality of a network by using graph representation learning algorithms and discretize the embedded space to convert it into an imagelike structure. We then creatively merge the nodal dynamical states with the structural embedding by multichannel images. In this manner, the proposed model can draw the conclusion from both structural and dynamical information. A large number of simulations show a great performance in both synthetic and empirical network data sets. Our end to end machine learning framework is robust and universally applicable to complex networks with arbitrary size and topology.

19.
Front Microbiol ; 10: 2591, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31781076

RESUMO

It is possible that arbuscular mycorrhizal fungi play a pivotal role in root development and Pb phytostabilization in plants grown in Pb-contaminated soil. In this study, a pot experiment was conducted over 4 months to evaluate the effects of Funneliformis mosseae strain BGCXJ01A on root characteristics of black locust (Robinia pseudoacacia L.) seedlings in Pb-contaminated soil. Four Pb treatments (0, 90, 900, and 3,000 mg kg-1) were applied to soil in the presence and absence of F. mosseae. Inoculation with F. mosseae prominently improved root length, surface area, volume, and tip number in the plants across all Pb treatments. The F. mosseae inoculation also increased root diameter and fork number, especially under high Pb treatments. The presence of F. mosseae significantly increased the root activity and root tolerance index. However, there was little difference in specific root length between inoculated and non-inoculated plants. The biomass of roots, stems, and leaves all increased following inoculation with F. mosseae. Inoculated plants had greater accumulation and translocation capacities for Pb in the roots and stems, but lower capacities were found in the leaves when compared with those in non-inoculated plants. These results highlight that F. mosseae can alleviate the toxic effects of Pb on root development and can immobilize Pb in the roots and stems of R. pseudoacacia grown in Pb-contaminated soil. This study provides a model system for phytoremediation of Pb-contaminated soil via reciprocal symbiosis between arbuscular mycorrhizal fungi and woody legumes.

20.
Opt Express ; 27(21): 29567-29580, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31684216

RESUMO

Nonlinear impairments induced by the opto-electronic components are one of the fundamental performance-limiting factors in high-speed optical short-reach communications, significantly hindering capacity improvement. This paper proposes to employ a kernel mapping function to map the signals in a Hilbert space to its inner product in a reproducing kernel Hilbert space, which has been successfully demonstrated to mitigate nonlinear impairments in optical short-reach communication systems. The operation principle is derived. An intensity modulation/direct detection system with 1.5-µm vertical cavity surface emitting laser and 10-km 7-core fiber achieving 540.68-Gbps (net-rate 505.31-Gbps) has been carried out. The experimental results reveal that the kernel mapping based schemes are able to realize comparable transmission performance as the Volterra filtering scheme even with a high order.

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