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In the field, necrosis area induced by pathogens is usually surrounded by a red circle in apple fruits. However, the underlying molecular mechanism of this phenomenon remains unclear. In this study, we demonstrated that accumulated salicylic acid (SA) induced by fungal infection promoted anthocyanin biosynthesis through MdNPR1-MdTGA2.2 module in apple (Malus domestica). Inoculating apple fruits with Valsa mali or Botryosphaeria dothidea induced a red circle surrounding the necrosis area, which mimicked the phenotype observed in the field. The red circle accumulated a high level of anthocyanins, which was positively correlated with SA accumulation stimulated by fungal invasion. Further analysis showed that SA promoted anthocyanin biosynthesis in a dose-dependent manner in both apple calli and fruits. We next demonstrated that MdNPR1, a master regulator of SA signaling, positively regulated anthocyanin biosynthesis in both apple and Arabidopsis. Moreover, MdNPR1 functioned as a co-activator to interact with and enhance the transactivation activity of MdTGA2.2, which could directly bind to the promoters of anthocyanin biosynthetic and regulatory genes to promote their transcription. Suppressing expression of either MdNPR1 or MdTGA2.2 inhibited coloration of apple fruits, while overexpressing either of them significantly promoted fruit coloration. Finally, we revealed that silencing either MdNPR1 or MdTGA2.2 in apple fruits repressed SA-induced fruit coloration. Therefore, our data determined that fungal-induced SA promoted anthocyanin biosynthesis through MdNPR1-MdTGA2.2 module, resulting in a red circle surrounding the necrosis area in apple fruits.
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Antocianinas , Ascomicetos , Frutas , Regulação da Expressão Gênica de Plantas , Malus , Doenças das Plantas , Proteínas de Plantas , Ácido Salicílico , Malus/microbiologia , Malus/genética , Malus/metabolismo , Ácido Salicílico/metabolismo , Antocianinas/biossíntese , Antocianinas/metabolismo , Ascomicetos/fisiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Frutas/microbiologia , Frutas/metabolismo , Frutas/genética , Arabidopsis/microbiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genéticaRESUMO
Spin-crossover (SCO) materials exhibit remarkable potential as bistable switches in molecular devices. However, the spin transition temperatures (Tc) of known compounds are unable to cover the entire ambient temperature spectrum, largely limiting their practical utility. This study reports an exemplary two-dimensional SCO solid solution system, [FeIII(H0.5LCl)2-2x(H0.5LF)2x]·H2O (H0.5LX = 5-X-2-hydroxybenzylidene-hydrazinecarbothioamide, X = F or Cl, x = 0 to 1), in which the adjacent layers are adhered via hydrogen bonding. Notably, the Tc of this system can be fine-tuned across 90 K (227-316 K) in a linear manner by modulating the fraction x of the LF ligand. Elevating x results in strengthened hydrogen bonding between adjacent layers, which leads to enhanced intermolecular interactions between adjacent SCO molecules. Single-crystal diffraction analysis and periodic density functional theory calculations revealed that such a special kind of alteration in interlayer interactions strengthens the FeIIIN2O2S2 ligand field and corresponding SCO energy barrier, consequently resulting in increased Tc. This work provides a new pathway for tuning the Tc of SCO materials through delicate manipulation of molecular interactions, which could expand the application of bistable molecular solids to a much wider temperature regime.
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Fruit colour is a critical determinant for the appearance quality and commercial value of apple fruits. Viroid-induced dapple symptom severely affects the fruit coloration, however, the underlying mechanism remains unknown. In this study, we identified an apple dimple fruit viroid (ADFVd)-derived small interfering RNA, named vsiR693, which targeted the mRNA coding for a bHLH transcription factor MdPIF1 (PHYTOCHROME-INTERACTING FACTOR 1) to regulate anthocyanin biosynthesis in apple. 5' RLM-RACE and artificial microRNA transient expression system proved that vsiR693 directly targeted the mRNA of MdPIF1 for cleavage. MdPIF1 positively regulated anthocyanin biosynthesis in both apple calli and fruits, and it directly bound to G-box element in the promoter of MdPAL and MdF3H, two anthocyanin biosynthetic genes, to promote their transcription. Expression of vsiR693 negatively regulated anthocyanin biosynthesis in both apple calli and fruits. Furthermore, co-expression of vsiR693 and MdPIF1 suppressed MdPIF1-promoted anthocyanin biosynthesis in apple fruits. Infiltration of ADFVd infectious clone suppressed coloration surrounding the injection sites in apple fruits, while a mutated version of ADFVd, in which the vsiR693 producing region was mutated, failed to repress fruit coloration around the injection sites. These data provide evidence that a viroid-derived small interfering RNA targets host transcription factor to regulate anthocyanin biosynthesis in apple.
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Molecule-based magnetic materials are useful candidates as the spin qubit due to their long coherence time and high designability. The anisotropy of the g-values of the metal complexes can be utilized to access the individual spin of the metal complexes, making it possible to achieve the scalable molecular spin qubit. For this goal, it is important to evaluate the effect of g-value anisotropy on the magnetic relaxation behaviour. This study reports the slow magnetic relaxation behaviour of chromium nitride (CrN2+ ) porphyrinato complex (1), which is structurally and magnetically similar with the vanadyl (VO2+ ) porphyrinato complex (2) which is known as the excellent spin qubit. Detailed analyses for vibrational and dynamical magnetism of 1 and 2 revealed that g-value anisotropy accelerates magnetic relaxations greater than the internal magnetic field from nuclear spin does. These results provide a design criterion for construction of multiple spin qubit based on g-tensor engineering.
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Heat shock protein 20 (Hsp20) is a small molecule heat shock protein that plays an important role in plant growth, development, and stress resistance. Little is known about the function of Hsp20 family genes in apple (Malus domestica). Here, we performed a genome-wide analysis of the apple Hsp20 gene family, and a total of 49 Hsp20s genes were identified from the apple genome. Phylogenetic analysis revealed that the 49 genes were divided into 11 subfamilies, and MdHsp18.2b, a member located in the CI branch, was selected as a representative member for functional characterization. Treatment with NaCl and Botryosphaeria dothidea (B. dothidea), the causal agent of apple ring rot disease, significantly induced MdHsp18.2b transcription level. Further analysis revealed that overexpressing MdHsp18.2b reduced the resistance to salt stress but enhanced the resistance to B. dothidea infection in apple calli. Moreover, MdHsp18.2b positively regulated anthocyanin accumulation in apple calli. Physiology assays revealed that MdHsp18.2b promoted H2O2 production, even in the absence of stress factors, which might contribute to its functions in response to NaCl and B. dothidea infection. Hsps usually function as homo- or heterooligomers, and we found that MdHsp18.2b could form a heterodimer with MdHsp17.9a and MdHsp17.5, two members from the same branch with MdHsp18.2b in the phylogenetic tree. Therefore, we identified 49 Hsp20s genes from the apple genome and found that MdHsp18.2b was involved in regulating plant resistance to salt stress and B. dothidea infection, as well as in regulating anthocyanin accumulation in apple calli.
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Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico HSP20 , Malus , Filogenia , Doenças das Plantas , Proteínas de Plantas , Malus/genética , Malus/microbiologia , Malus/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Proteínas de Choque Térmico HSP20/genética , Proteínas de Choque Térmico HSP20/metabolismo , Ascomicetos/fisiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Família Multigênica , Resistência à Doença/genética , Antocianinas/metabolismoRESUMO
Plants possess the remarkable ability to sense detrimental environmental stimuli and launch sophisticated signal cascades that culminate in tailored responses to facilitate their survival, and transcription factors (TFs) are closely involved in these processes. Phytochrome interacting factors (PIFs) are among these TFs and belong to the basic helix-loop-helix family. PIFs are initially identified and have now been well established as core regulators of phytochrome-associated pathways in response to the light signal in plants. However, a growing body of evidence has unraveled that PIFs also play a crucial role in adapting plants to various biological and environmental pressures. In this review, we summarize and highlight that PIFs function as a signal hub that integrates multiple environmental cues, including abiotic (i.e., drought, temperature, and salinity) and biotic stresses to optimize plant growth and development. PIFs not only function as transcription factors to reprogram the expression of related genes, but also interact with various factors to adapt plants to harsh environments. This review will contribute to understanding the multifaceted functions of PIFs in response to different stress conditions, which will shed light on efforts to further dissect the novel functions of PIFs, especially in adaption to detrimental environments for a better survival of plants.
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Proteínas de Arabidopsis , Fitocromo , Fitocromo/genética , Fitocromo/metabolismo , Proteínas de Arabidopsis/genética , Transdução de Sinais/genética , Regulação da Expressão Gênica de Plantas , Plantas/genética , Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Estresse Fisiológico , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismoRESUMO
Plant secondary metabolites are well known for their biological functions in defending against pathogenic microorganisms. Tea saponin (TS), one type of secondary metabolite of the tea plant (Camellia sinensis), has been shown to be a valuable botanical pesticide. However, its antifungal activity in controlling the fungi Valsa mali, Botryosphaeria dothidea, and Alternaria alternata, which induce major diseases in apple (Malus domestica), has not been determined. In this study, we first determined that TS has higher inhibitory activity than catechins against the three types of fungi. We further utilized in vitro and in vivo assays to confirm that TS showed high antifungal activity against the three types of fungi, especially for V. mali and B. dothidea. In the in vivo assay, application of a 0.5% TS solution was able to restrain the fungus-induced necrotic area in detached apple leaves efficiently. Moreover, a greenhouse infection assay also confirmed that TS treatment significantly inhibited V. mali infection in leaves of apple seedlings. In addition, TS treatment activated plant immune responses by decreasing accumulation of reactive oxygen species and promoting the activity of pathogenesis-related proteins, including chitinase and ß-1,3-glucanase. This indicated that TS might serve as a plant defense inducer to activate innate immunity to fight against fungal pathogen invasion. Therefore, our data indicated that TS might restrain fungal infection in two ways, by directly inhibiting the growth of fungi and by activating plant innate defense responses as a plant defense inducer.
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Malus , Malus/microbiologia , Antifúngicos/farmacologia , Antifúngicos/metabolismo , Proteínas de Plantas/metabolismo , Doenças das Plantas/microbiologia , Chá/metabolismoRESUMO
Objective: To investigate the value of mesenteric CTA combined with D-dimer (DD) level and inflammatory factor changes in evaluating the severity of mesenteric artery embolism. Methods: This is a retrospective study. The imaging data of mesenteric CTA and the levels of plasma DD and inflammatory factors in 120 patients with mesenteric artery embolism confirmed by DSA or surgery in Baoding No.1 Central Hospital were analyzed retrospectively from January 2021 to December 2022. The coincidence rate of CTA alone and CTA combined with DD and inflammatory factors with the results of surgery or DSA was compared and analyzed. The specificity, sensitivity and accuracy of CTA alone and CTA combined with DD and inflammatory factors in diagnosing superior mesenteric artery embolism were compared. The correlations of different severity of mesenteric artery embolism with DD and inflammatory factor levels were compared and analyzed. Results: There was a significant difference in the coincidence rate between CTA diagnosis and CTA combined with DD and inflammatory factors diagnosis (p= 0.01). And the sensitivity and accuracy of the latter were significantly higher than those of the former (sensitivity, p= 0.01; accuracy, p= 0.00). The levels of plasma DD, TNF-a, CRP and IL-6 in the intestinal wall thinning group were significantly higher than those in the thickening group (p= 0.00). The above indexes increased significantly in the decreased intestinal wall enhancement group compared with the increased intestinal wall enhancement group (p= 0.00). DD, TNF-É, CRP and IL-6 levels increased with the increase in stenosis severity. Conclusion: Mesenteric CTA combined with plasma DD and inflammatory factor levels can effectively determine the severity of mesenteric arterial embolism, and provide a scientific basis for early clinical diagnosis and treatment.
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The hitherto elusive benzo[c]anthanthrenyl radical derivatives composed of seven fused six-membered rings are synthesized and isolated in the crystalline form, representing a laterally π-extended doublet open-shell graphene fragment compared to the phenalenyl and olympicenyl radical structures. X-ray crystallographic analysis revealed one-dimensional chain stacking with relatively close intermolecular contacts, which is an important precondition for achieving single-component conductors. The magnetic, optical, and redox properties are investigated in the solution phase. In combination with the good stability, such open-shell molecular systems have potentials as functional electronic materials.
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Hybrid organic-inorganic piezoelectrics have attracted attention due to their simple synthesis, mechanical flexibility, and designability, which have promising application potential in flexible sensing and self-powered energy harvesting devices. Although some hybrid piezoelectrics are discovered, most of their structures are limited by the perovskite-type and often contain lead. Herein, the synthesis, structure, and piezoelectric properties of a new hybrid lead-free metal halide, (BTMA)2 CoBr4 (BTMA = benzyltrimethylammonium) are reported. The experimental and theoretical results demonstrate that this material simply composed of [CoBr4 ]2- tetrahedra and BTMA+ cations exhibits significant piezoelectricity (d22 = 5.14, d25 = 12.40 pC N-1 ), low Young's and shear moduli (4.11-17.56 GPa; 1.86-7.91 GPa). Moreover, the (BTMA)2 CoBr4 /PDMS (PDMS = polydimethylsiloxane) composite thin films are fabricated and optimized. The 10% (BTMA)2 CoBr4 /PDMS-based flexible devices show attractive performance in energy harvesting with an open-circuit voltage of 19.70 V, short-circuit current of 4.24 µA, and powder density of 11.72 µW cm-2 , catching up with those of piezoelectric ceramic composites. Meanwhile, these film devices show excellent capability in accurately sensing human body motions, such as finger bending and tapping. This work demonstrates that (BTMA)2 CoBr4 and related piezoelectric lead-free halides can be promising molecular materials in modern energy and sensing applications.
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Movimento (Física) , HumanosRESUMO
Taking advantage of the pentaethylene glycol (EO5) and deprotonation of EO5, a family of new structurally hexagonal bipyramidal Dy(III) complexes, [Dy(EO5)(2,6-dichloro-4-nitro-PhO)2](2,6-dichloro-4-nitro-PhO) (1), [Dy(EO5-BPh2)(2,6-dichloro-4-nitro-PhO)2] (2), and [Dy(EO5-BPh2)(2,6-dichloro-4-nitro-PhO)Cl] (3), were controbllably synthesized and structurally characterized. Magnetic measurements show that complex 1 is a zero-field SIM and has an observable hysteresis opening up to 4 K. Conversely, only under extra magnetic field is slow magnetic relaxation observed in 2 and 3. This considerable difference in the magnetic behavior is mainly caused by the change of the equatorial negative charge. Detailed ab initio calculations further elucidate that the quantum tunneling is induced by the presence of equatorial negative charge, and the magnetic anisotropy depends on the axial ligands. This work demonstrates that the absence of the equatorial negative charge should also be considered in the rational design of promising single molecular magnets based on the oblate ions.
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In condensed matter, phase separation is strongly related to ferroelasticity, ferroelectricity, ferromagnetism, electron correlation, and crystallography. These ferroics are important for nano-electronic devices such as non-volatile memory. However, the quantitative information regarding the lattice (atomic) structure at the border of phase separation is unclear in many cases. Thus, to design electronic devices at the molecular level, a quantitative electron-lattice relationship must be established. Herein, we elucidated a PdII-PdIV/PdIII-PdIII phase transition and phase separation mechanism for [Pd(cptn)2Br]Br2 (cptn = 1R,2R-diaminocyclopentane), propagated through a hydrogen-bonding network. Although the Pd···Pd distance was used to determine the electronic state, the differences in the Pd···Pd distance and the optical gap between Mott-Hubbard (MH) and charge-density-wave (CDW) states were only 0.012 Å and 0.17 eV, respectively. The N-H···Br···H-N hydrogen-bonding network functioned as a jack, adjusting the structural difference dynamically, and allowing visible ferroelastic phase transition/separation in a fluctuating N2 gas flow. Additionally, the effect of the phase separation on the spin susceptibility and electrical conductivity were clarified to represent the quasi-epitaxial crystals among CDW-MH states. These results indicate that the phase transitions and separations could be controlled via atomic and molecular level modifications, such as the addition of hydrogen bonding.
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The daily life of people in the intelligent age is inseparable from electronic device, and a number of bacteria on touch screens are increasingly threatening the health of users. Herein, a photocatalytic TiO2/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction. Ultraviolet-visible (UV-Vis) spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO2. The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO2/Ag film against S. aureus and E. coli was 98.2% and 98.6%, under visible light irradiation for 5 min. The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO2 reduced the bandgap of TiO2 from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO2 and Ag. Thus, TiO2/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens. More importantly, the TiO2/Ag film had great biocompatibility with/without light irradiation. The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.
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BACKGROUND: To identify candidate key genes and pathways related to resting mast cells in meningioma and the underlying molecular mechanisms of meningioma. METHODS: Gene expression profiles of the used microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. GO and KEGG pathway enrichments of DEGs were analyzed using the ClusterProfiler package in R. The protein-protein interaction network (PPI), and TF-miRNA- mRNA co-expression networks were constructed. Further, the difference in immune infiltration was investigated using the CIBERSORT algorithm. RESULTS: A total of 1499 DEGs were identified between tumor and normal controls. The analysis of the immune cell infiltration landscape showed that the probability of distribution of memory B cells, regulatory T cells (Tregs), and resting mast cells in tumor samples were significantly higher than those in the controls. Moreover, through WGCNA analysis, the module related to resting mast cells contained 158 DEGs, and KEGG pathway analysis revealed that the DEGs were dominant in the TNF signaling pathway, cytokine-cytokine receptor interaction, and IL-17 signaling pathway. Survival analysis of hub genes related to resting mast cells showed that the risk model was constructed based on 9 key genes. The TF-miRNA- mRNA co-regulation network, including MYC-miR-145-5p, TNFAIP3-miR-29c-3p, and TNFAIP3-hsa-miR-335-3p, were obtained. Further, 36 nodes and 197 interactions in the PPI network were identified. CONCLUSION: The results of this study revealed candidate key genes, miRNAs, and pathways related to resting mast cells involved in meningioma development, providing potential therapeutic targets for meningioma treatment.
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Perfilação da Expressão Gênica , Mastócitos/citologia , Neoplasias Meníngeas/genética , Meningioma/genética , Algoritmos , Bases de Dados Genéticas , Humanos , Imunidade Celular , Interleucina-17/metabolismo , Células B de Memória/citologia , Neoplasias Meníngeas/imunologia , Neoplasias Meníngeas/patologia , Meningioma/imunologia , Meningioma/patologia , MicroRNAs/metabolismo , Mapas de Interação de Proteínas , Transdução de Sinais , Linfócitos T Reguladores/citologiaRESUMO
The seriousness of the energy crisis and the environmental impact of global anthropogenic activities have led to an urgent need to develop efficient and green fuels. Hydrogen, as a promising alternative resource that is produced in an environmentally friendly and sustainable manner by a water splitting reaction, has attracted extensive attention in recent years. However, the large-scale application of water splitting devices is hindered predominantly by the sluggish oxygen evolution reaction (OER) at the anode. Therefore, the design and exploration of high-performing OER electrocatalysts is a critical objective. Considering their low prices, abundant reserves, and intrinsic activities, NiFe-based bimetal compounds are widely studied as excellent OER electrocatalysts. Moreover, recent progress on NiFe-based OER electrocatalysts in alkaline environments is comprehensively and systematically introduced through various catalyst families including NiFe-layered hydroxides, metal-organic frameworks, NiFe-based (oxy)hydroxides, NiFe-based oxides, NiFe alloys, and NiFe-based nonoxides. This review briefly introduces the advanced NiFe-based OER materials and their corresponding reaction mechanisms. Finally, the challenges inherent to and possible strategies for producing extraordinary NiFe-based electrocatalysts are discussed.
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BACKGROUND: This study was intended to investigate the genomic landscape of the immune microenvironments of brain metastases in breast cancer. METHODS: Three gene expression profile datasets (GSE76714, GSE125989 and GSE43837) of breast cancer with brain metastases were downloaded from Gene Expression Omnibus (GEO) database. After differential expression analysis, the tumor immune microenvironment and immune cell infiltration were analyzed. Then immune-related genes were identified, followed by function analysis, transcription factor (TF)-miRNA-mRNA co-regulatory network analysis, and survival analysis of metastatic recurrence. RESULTS: The present results showed that the tumor immune microenvironment in brain metastases was immunosuppressed compared with primary caner. Compared with primary cancer samples, the infiltration ratio of plasma cells in brain metastases samples was significantly higher, while the infiltration ratio of macrophages M2 cells in brain metastases samples was significantly lower. Total 42 immune-related genes were identified, such as THY1 and NEU2. CD1B, THY1 and DOCK2 were found to be implicated in the metastatic recurrence of breast cancer. CONCLUSIONS: Targeting macrophages or plasma cells may be new strategies for immunotherapy of breast cancer with brain metastases. THY1 and NEU2 may be potential therapeutic targets for breast cancer with brain metastases, and THY1, CD1B and DOCK2 may serve as potential prognostic markers for improvement of brain metastases survival.
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Neoplasias Encefálicas , Neoplasias da Mama , Neoplasias Encefálicas/genética , Mama , Neoplasias da Mama/genética , Genômica , Humanos , Microambiente TumoralRESUMO
BACKGROUND AND AIMS: Glioblastoma (GBM) is a common and aggressive primary brain tumor, and the prognosis for GBM patients remains poor. This study aimed to identify the key genes associated with the development of GBM and provide new diagnostic and therapies for GBM. METHODS: Three microarray datasets (GSE111260, GSE103227, and GSE104267) were selected from Gene Expression Omnibus (GEO) database for integrated analysis. The differential expressed genes (DEGs) between GBM and normal tissues were identified. Then, prognosis-related DEGs were screened by survival analysis, followed by functional enrichment analysis. The protein-protein interaction (PPI) network was constructed to explore the hub genes associated with GBM. The mRNA and protein expression levels of hub genes were respectively validated in silico using The Cancer Genome Atlas (TCGA) and Human Protein Atlas (HPA) databases. Subsequently, the small molecule drugs of GBM were predicted by using Connectivity Map (CMAP) database. RESULTS: A total of 78 prognosis-related DEGs were identified, of which10 hub genes with higher degree were obtained by PPI analysis. The mRNA expression and protein expression levels of CETN2, MKI67, ARL13B, and SETDB1 were overexpressed in GBM tissues, while the expression levels of CALN1, ELAVL3, ADCY3, SYN2, SLC12A5, and SOD1 were down-regulated in GBM tissues. Additionally, these genes were significantly associated with the prognosis of GBM. We eventually predicted the 10 most vital small molecule drugs, which potentially imitate or reverse GBM carcinogenic status. Cycloserine and 11-deoxy-16,16-dimethylprostaglandin E2 might be considered as potential therapeutic drugs of GBM. CONCLUSIONS: Our study provided 10 key genes for diagnosis, prognosis, and therapy for GBM. These findings might contribute to a better comprehension of molecular mechanisms of GBM development, and provide new perspective for further GBM research. However, specific regulatory mechanism of these genes needed further elaboration.
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Invited for the cover of this issue are Ryuta Ishikawa and Satoshi Kawata at Fukuoka University and co-workers at Osaka University, Tohoku University, and Kumamoto University, Japan, collaborating within the research project "SOFT CRYSTALS". The image depicts the thermally induced simultaneous switching of magnetism and electrical conductivity in a two-dimensional supramolecular architecture composed of dinuclear FeII spin-crossover complexes and partially charged 7,7',8,8'-tetracyano-p-quinodimethanide radicals. 10.1002/chem.201903934.
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The reaction of Fe(OAc)2 and Hbpypz with neutral TCNQ results in the formation of [Fe2 (bpypz)2 (TCNQ)2 ](TCNQ)2 (1), in which Hbpypz=3,5-bis(2-pyridyl)pyrazole and TCNQ=7,7',8,8'-tetracyano-p-quinodimethane. Crystal packing of 1 with uncoordinated TCNQ and π-π stacking of bpypz- ligands produces an extended two-dimensional supramolecular coordination assembly. Temperature dependence of the dc magnetic susceptibility and heat capacity measurements indicate that 1 undergoes an abrupt spin crossover (SCO) with thermal spin transition temperatures of 339 and 337â K for the heating and cooling modes, respectively, resulting in a thermal hysteresis of 2â K. Remarkably, the temperature dependence of dc electrical transport exhibits a transition that coincides with thermal SCO, demonstrating the thermally induced magnetic and electrical bistability of 1, strongly correlating magnetism with electrical conductivity. This outstanding feature leads to thermally induced simultaneous switching of magnetism and electrical conductivity and a magnetoresistance effect.
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The first three-dimensional (3D) conductive single-ion magnet (SIM), (TTF)2 [Co(pdms)2 ] (TTF=tetrathiafulvalene and H2 pdms=1,2-bis(methanesulfonamido)benzene), was electrochemically synthesised and investigated structurally, physically, and theoretically. The similar oxidation potentials of neutral TTF and the molecular precursor [HNEt3 ]2 [M(pdms)2 ] (M=Co, Zn) allow for multiple charge transfers (CTs) between the SIM donor [M(pdms)2 ]n- and the TTF.+ acceptor, as well as an intradonor CT from the pdms ligand to Co ion upon electrocrystallisation. Usually TTF functions as a donor, whereas in our system TTF is both a donor and an accepter because of the similar oxidation potentials. Furthermore, the [M(pdms)2 ]n- donor and TTF.+ acceptor are not segregated but strongly interact with each other, contrary to reported layered donor-acceptor electrical conductors. The strong intermolecular and intramolecular interactions, combined with CT, allow for relatively high electrical conductivity even down to very low temperatures. Furthermore, SIM behaviour with slow magnetic relaxation and opening of hysteresis loops was observed. (TTF)2 [Co(pdms)2 ] (2-Co) is an excellent building block for preparing new conductive SIMs.