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Majorana bound states constitute one of the simplest examples of emergent non-Abelian excitations in condensed matter physics. A toy model proposed by Kitaev shows that such states can arise at the ends of a spinless p-wave superconducting chain1. Practical proposals for its realization2,3 require coupling neighbouring quantum dots (QDs) in a chain through both electron tunnelling and crossed Andreev reflection4. Although both processes have been observed in semiconducting nanowires and carbon nanotubes5-8, crossed-Andreev interaction was neither easily tunable nor strong enough to induce coherent hybridization of dot states. Here we demonstrate the simultaneous presence of all necessary ingredients for an artificial Kitaev chain: two spin-polarized QDs in an InSb nanowire strongly coupled by both elastic co-tunnelling (ECT) and crossed Andreev reflection (CAR). We fine-tune this system to a sweet spot where a pair of poor man's Majorana states is predicted to appear. At this sweet spot, the transport characteristics satisfy the theoretical predictions for such a system, including pairwise correlation, zero charge and stability against local perturbations. Although the simple system presented here can be scaled to simulate a full Kitaev chain with an emergent topological order, it can also be used imminently to explore relevant physics related to non-Abelian anyons.
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We report an experimental study of a 1D quintuple-quantum-dot array integrated with two charge sensors in an InAs nanowire. The device is studied by measuring double quantum dots formed consecutively in the array, and corresponding charge stability diagrams are revealed with both direct current measurements and charge sensor signals. The one-dimensional quintuple-quantum-dot array is then tuned up, and its charge configurations are fully mapped out with the two charge sensors. The energy level of each dot in the array can be controlled individually using virtual gates. After that, four dots in the array are selected to form two double quantum dots, and ultrastrong inter-double-dot interaction is obtained. A theoretical simulation confirms the strong coupling strength between the two double quantum dots. The highly controllable one-dimensional quantum dot array is expected to be valuable for employing InAs nanowires to construct advanced quantum hardware in the future.
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We study the current-phase relation (CPR) of an InSb-Al nanowire Josephson junction in parallel magnetic fields up to 700 mT. At high magnetic fields and in narrow voltage intervals of a gate under the junction, the CPR exhibits π shifts. The supercurrent declines within these gate intervals and shows asymmetric gate voltage dependence above and below them. We detect these features sometimes also at zero magnetic field. The observed CPR properties are reproduced by a theoretical model of supercurrent transport via interference between direct transmission and a resonant localized state.
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Under certain symmetry-breaking conditions, a superconducting system exhibits asymmetric critical currents, dubbed the "superconducting diode effect." Recently, systems with the ideal superconducting diode efficiency or unidirectional superconductivity have received considerable interest. In this work, we report the study of Al-InAs nanowire-Al Josephson junctions under microwave irradiation and magnetic fields. We observe an enhancement of superconducting diode effect under microwave driving, featured by a horizontal offset of the zero-voltage step in the voltage-current characteristic that increases with microwave power. Devices reach the unidirectional superconductivity regime at sufficiently high driving amplitudes. The offset changes sign with the reversal of the magnetic field direction. Meanwhile, the offset magnitude exhibits a roughly linear response to the microwave power in dBm when both the power and the magnetic field are large. The signatures observed are reminiscent of a recent theoretical proposal using the resistively shunted junction (RSJ) model. However, the experimental results are not fully explained by the RSJ model, indicating a new mechanism for unidirectional superconductivity that is possibly related to nonequilibrium dynamics or dissipation in periodically driven superconducting systems.
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We report an experimental study of proximity induced superconductivity in planar Josephson junction devices made from free-standing InAs nanosheets. The nanosheets are grown by molecular beam epitaxy, and the Josephson junction devices are fabricated by directly contacting the nanosheets with superconductor Al electrodes. The fabricated devices are explored by low-temperature carrier transport measurements. The measurements show that the devices exhibit a gate-tunable supercurrent, multiple Andreev reflections, and a good quality superconductor-semiconductor interface. The superconducting characteristics of the Josephson junctions are investigated at different magnetic fields and temperatures and are analyzed based on the Bardeen-Cooper-Schrieffer (BCS) theory. The measurements of the ac Josephson effect are also conducted under microwave radiations with different radiation powers and frequencies, and integer Shapiro steps are observed. Our work demonstrates that InAs nanosheet based hybrid devices are desired systems for investigating the forefront of physics, such as two-dimensional topological superconductivity.
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Semiconducting nanowire Josephson junctions represent an attractive platform to investigate the anomalous Josephson effect and detect topological superconductivity. However, an external magnetic field generally suppresses the supercurrent through hybrid nanowire junctions and significantly limits the field range in which the supercurrent phenomena can be studied. In this work, we investigate the impact of the length of InSb-Al nanowire Josephson junctions on the supercurrent resilience against magnetic fields. We find that the critical parallel field of the supercurrent can be considerably enhanced by reducing the junction length. Particularly, in 30 nm long junctions supercurrent can persist up to 1.3 T parallel fieldâapproaching the critical field of the superconducting film. Furthermore, we embed such short junctions into a superconducting loop and obtain the supercurrent interference at a parallel field of 1 T. Our findings are highly relevant for multiple experiments on hybrid nanowires requiring a magnetic-field-resilient supercurrent.
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The tachinid fly, Exorista sorbillans, is a notorious ovolarviparous endoparasitoid of the silkworm, Bombyx mori, causing severe damage to silkworm cocoon industry. Silkworm larvae show typically precocious wandering behavior after being parasitized by E. sorbillans; however, the underlying molecular mechanism remains unexplored. Herein, we investigated the changes in the levels of 20-hydroxyecdysone (20E) and juvenile hormone (JH) titer, and they both increased in the hemolymph of parasitized silkworms. Furthermore, we verified the expression patterns of related genes, which showed an upregulation of 20E signaling and biosynthesis genes but a significant downregulation of ecdysone oxidase (EO), a 20E inactivation enzyme, in parasitized silkworms. In addition, related genes of the JH signaling were activated in parasitized silkworms, while related genes of the JH degradation pathway were suppressed, resulting in an increase in JH titer. Notably, the precocious wandering behavior of parasitized silkworms was partly recoverable by silencing the transcriptions of BmCYP302A1 or BmCYP307A1 genes. Our findings suggest that the developmental duration of silkworm post parasitism could be shortened by regulation of 20E and JH titers, which may help silkworm to resist the E. sorbillans infestation. These findings provide a basis for deeper insight into the interplay between silkworms and E. sorbillans and may serve as a reference for the development of a novel approach to control silkworm myiasis.
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Bombyx , Dípteros , Lepidópteros , Manduca , Animais , Dípteros/metabolismo , Larva , Ecdisona/metabolismo , Lepidópteros/metabolismo , Hormônios Juvenis/metabolismoRESUMO
Aberrant protein N-glycosylation is a cancer hallmark, which has great potential for cancer detection. However, large-scale and in-depth analysis of N-glycosylation remains challenging because of its high heterogeneity, complexity, and low abundance. Human saliva is an attractive diagnostic body fluid, while few efforts explored its N-glycoproteome for lung cancer. Here, we utilized a zwitterionic-hydrophilic interaction chromatography-based strategy to specifically enrich salivary glycopeptides. Through quantitative proteomics analysis, 1492 and 1234 intact N-glycopeptides were confidently identified from pooled saliva samples of 10 subjects in the nonsmall-cell lung cancer group and 10 subjects in the normal control group. Accordingly, 575 and 404 N-glycosites were revealed for the lung cancer group and normal control group. In particular, 154 N-glycosites and 259 site-specific glycoforms were significantly dysregulated in the lung cancer group. Several N-glycosites located at the same glycoprotein and glycans attached to the same N-glycosites were observed with differential expressions, including haptoglobin, Mucin-5B, lactotransferrin, and α-1-acid glycoprotein 1. These N-glycoproteins were mainly related to inflammatory responses, infectious diseases, and cancers. Our study achieved comprehensive characterization of salivary N-glycoproteome, and dysregulated site-specific glycoforms hold promise for noninvasive detection of lung cancer.
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Neoplasias Pulmonares , Saliva , Glicopeptídeos/análise , Glicoproteínas/metabolismo , Humanos , Neoplasias Pulmonares/diagnóstico , Proteoma/metabolismo , Proteômica , Saliva/químicaRESUMO
The development of novel stationary phases with specific functionality is of great importance in chromatographic separation. Herein, we fabricated fluoro-functionalized spherical covalent organic frameworks (SF-COFs) via a bottom-up strategy as stationary phases for high-performance liquid chromatography (HPLC). Benefiting from the significant monodispersity, narrow size distribution, and high fluorine content, the SF-COFs packed column showed high column efficiency and excellent resolution for the separation of the organic fluorides involving polyfluorobenzenes, polychlorobenzenes, polybromobenzenes, perfluoroalkyl methacrylates, and halogenated trifluorotoluenes, which cannot be separated on the fluorine-free spherical covalent organic frameworks packed column. Especially, the column efficiency of 20â¯100-38â¯500 plates/m was obtained for polyfluorobenzenes, and the relative standard deviations of the retention time for continuous 10 separations of polychlorobenzenes and polybromobenzenes were less than 0.98%. Furthermore, the prepared SF-COFs packed column showed overwhelming superiority in the separation of organic halides compared with commercial C18 and pentafluorophenyl (PFP) packed columns. In addition, the compounds with different hydrophobicity or aromatic ring structure were also successfully separated on the SF-COFs packed column. This work extended the application of spherical COFs and provided a new way to introduce specific functional groups into the COF-based stationary phase for HPLC.
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Compostos Inorgânicos , Estruturas Metalorgânicas , Estruturas Metalorgânicas/química , Cromatografia Líquida de Alta Pressão/métodosRESUMO
BACKGROUND: Many stage II/III colorectal cancer (CRC) patients may relapse after routine treatments. Aberrant phosphorylation can regulate pathophysiological processes of tumors, and finding characteristic protein phosphorylation is an efficient approach for the prediction of CRC relapse. RESEARCH DESIGN AND METHODS: We compared the tissue proteome and phosphoproteome of stage II/III CRC patients between the relapsed group (n = 5) and the non-relapsed group (n = 5). Phosphopeptides were enriched with Ti4+-IMAC material. We utilized label-free quantification-based proteomics to screen differentially expressed proteins and phosphopeptides between the two groups. Gene Ontology (GO) analysis and Ingenuity Pathway Analysis (IPA) were used for bioinformatics analysis. RESULTS: The immune response of the relapsed group (Z-score -2.229) was relatively poorer than that of the non-relapsed group (Z-score 1.982), while viability of tumor was more activated (Z-score 2.895) in the relapsed group, which might cause increased relapse risk. The phosphorylation degrees of three phosphosites (phosphosite 1362 of TP53BP1, phosphosite 809 of VCL and phosphosite 438 of STK10) might be reliable prognostic biomarkers. CONCLUSIONS: Some promising proteins and phosphopeptides were discovered to predict the relapse risk in postoperative follow-ups.
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Neoplasias Colorretais , Fosfopeptídeos , Humanos , Fosfopeptídeos/metabolismo , Proteômica , Neoplasias Colorretais/metabolismo , Proteoma/metabolismo , FosforilaçãoRESUMO
Extracellular vesicles (EVs) play critical roles in intercellular communications, which contain valuable biomarkers for the detection of cancers. Phosphoproteomics analysis of human saliva EVs (sEVs) can help to discover lung cancer-related candidates. Due to the low abundance of phosphoproteins in sEVs, an efficient, reproducible, and cost-effective strategy is required for their enrichment. Here, we compared the latest phosphopeptide techniques, including TiO2, ZrO2, CaTiO3, and Ti4+-IMAC (immobilized metal affinity chromatography) methods, for phosphopeptide isolation. Our data demonstrated that Ti4+-IMAC was the superior one. By using the optimized Ti4+-IMAC approach, we identified more than 500 sEV phosphopeptides. Quantitative proteomics was employed to comprehensively decipher the sEV phosphoproteome of the normal group (n = 6) and lung cancer group (n = 6). Accordingly, 524 and 333 phosphopeptides were enriched, respectively, which corresponded to 439 and 282 phosphoproteins. In total, 857 unique sEV phosphopeptides corresponding to 721 phosphoproteins were revealed. Among 493 identified phosphosites, 37 were upregulated (> 1.5) and 217 were downregulated (< 0.66) in the cancer group. Our data collectively demonstrated that Ti4+-IMAC is an efficient and reproducible technology for comprehensive analysis of sEV phosphoproteome. Differentially expressed sEV phosphoproteins and phosphosites might be used for the detection of lung cancer non-invasively.
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Vesículas Extracelulares , Neoplasias Pulmonares , Cromatografia de Afinidade/métodos , Vesículas Extracelulares/química , Humanos , Neoplasias Pulmonares/diagnóstico , Fosfopeptídeos/análise , Fosfoproteínas , Proteoma , Titânio/químicaRESUMO
We have measured the Zeeman splitting of quantum levels in few-electron quantum dots (QDs) formed in narrow bandgap InSb nanowires via the Schottky barriers at the contacts under application of different spatially orientated magnetic fields. The effective g-factor tensor extracted from the measurements is strongly anisotropic and level-dependent, which can be attributed to the presence of strong spin-orbit interaction (SOI) and asymmetric quantum confinement potentials in the QDs. We have demonstrated a successful determination of the principal values and the principal axis orientations of the g-factor tensors in an InSb nanowire QD by the measurements under rotations of a magnetic field in the three orthogonal planes. We also examine the magnetic field evolution of the excitation spectra in an InSb nanowire QD and extract a SOI strength of [Formula: see text] â¼ 180 µeV from an avoided level crossing between a ground state and its neighboring first excited state in the QD.
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The ROS1 fusion kinase is an attractive antitumor target. Though with significant clinical efficacy, the well-known first-generation ROS1 inhibitor (ROS1i) crizotinib inevitably developed acquired resistance due to secondary point mutations in the ROS1 kinase. Novel ROS1is effective against mutations conferring secondary crizotinib resistance, especially G2032R, are urgently needed. In the present study, we evaluated the antitumor efficacy of SAF-189s, the new-generation ROS1/ALK inhibitor, against ROS1 fusion wild-type and crizotinib-resistant mutants. We showed that SAF-189s potently inhibited ROS1 kinase and its known acquired clinically resistant mutants, including the highly resistant G2032R mutant. SAF-189s displayed subnanomolar to nanomolar IC50 values against ROS1 wild-type and mutant kinase activity and a selectivity vs. other 288 protein kinases tested. SAF-189s blocked cellular ROS1 signaling, and in turn potently inhibited the cell proliferation in HCC78 cells and BaF3 cells expressing ROS1 fusion wild-type and resistance mutants. In nude mice bearing BaF3/CD74-ROS1 or BaF3/CD74-ROS1G2032R xenografts, oral administration of SAF-189s dose dependently suppressed the growth of both ROS1 wild-type- and G2032R mutant-driven tumors. In a patient-derived xenograft model of SDC4-ROS1 fusion NSCLC, oral administration of SAF-189s (20 mg/kg every day) induced tumor regression and exhibited notable prolonged and durable efficacy. In addition, SAF-189s was more potent than crizotinib and comparable to lorlatinib, the most advanced ROS1i known against the ROS1G2032R. Collectively, these results suggest the promising potential of SAF-189s for the treatment of patients with the ROS1 fusion G2032R mutation who relapse on crizotinib. It is now recruiting both crizotinib-relapsed and naive ROS1-positive NSCLC patients in a multicenter phase II trial (ClinicalTrials.gov Identifier: NCT04237805).
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Antineoplásicos/uso terapêutico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Crizotinibe/uso terapêutico , Feminino , Humanos , Camundongos Nus , Mutação , Neoplasias/enzimologia , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Fibroblast growth factor receptor (FGFR) is a promising anticancer target. Currently, most FGFR inhibitors lack sufficient selectivity and have nonnegligible activity against kinase insert domain receptor (KDR), limiting their feasibility due to the serious side effects. Notably, compensatory activation occurs among FGFR1-4, suggesting the urgent need to develop selective pan-FGFR1-4 inhibitors. Here, we explored the antitumor activity of DW14383, a novel irreversible FGFR1-4 inhibitor. DW14383 exhibited equivalently high potent inhibition against FGFR1, 2, 3 and 4, with IC50 values of less than 0.3, 1.1, less than 0.3, and 0.5 nmol/L, respectively. It is a selective FGFR inhibitor, exhibiting more than 1100-fold selectivity for FGFR1 over recombinant KDR, making it one of the most selective FGFR inhibitors over KDR described to date. Furthermore, DW14383 significantly inhibited cellular FGFR1-4 signaling, inducing G1/S cell cycle arrest, which in turn antagonized FGFR-dependent tumor cell proliferation. In contrast, DW14383 had no obvious antiproliferative effect against cancer cell lines without FGFR aberration, further confirming its selectivity against FGFR. In representative FGFR-dependent xenograft models, DW14383 oral administration substantially suppressed tumor growth by simultaneously inhibiting tumor proliferation and angiogenesis via inhibiting FGFR signaling. In summary, DW14383 is a promising selective irreversible pan-FGFR inhibitor with pan-tumor spectrum potential in FGFR1-4 aberrant cancers, which has the potential to overcome compensatory activation among FGFR1-4.
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Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Receptores de Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Administração Oral , Animais , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Neoplasias/metabolismo , Neoplasias/patologia , Inibidores de Proteínas Quinases/farmacologia , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Human microbiome contains billions of microorganisms that play important roles in the biological system and different diseases. Due to its complexity, conventional culture-independent technology may underestimate the value of low-abundance bacteria, which calls for a highly efficient method for its enrichment and comprehensive analysis. In this study, we developed a recycling free-flow isoelectric focusing (RFFIEF) method-based electrophoresis method to separate salivary microbiome. First, we used Escherichia coli (DH5α) as a model for RFFIEF method development, which was focused in a narrow pH range (0.38 pH unit). The recovery rate was 80.81% with 5.85% relative standard deviation (n = 5). The optimized method was then adopted to separate the human salivary microbiome into 32 fractions, followed by 16S rRNA gene sequencing and metaproteomics analysis. After RFFIEF fractionation, we identified 508 bacterial genera, which increased by 225% on average (n = 3) when compared to the results before fractionation. We further compared the compositional change of microbiome in the saliva of lung cancer group (n = 22) and control group (n = 21) through RFFIEF. Quantitative results demonstrated that six bacterial genera were upregulated dramatically in the lung cancer group, while two genera were downregulated. Through qPCR verification in an independent sample set (n = 48), we confirmed that genus Granulicatella was significantly upregulated in the lung cancer group, whereas Pseudomonas was remarkably downregulated (p < 0.001). RFFIEF is an efficient and reproducible technology to fractionate the microbiome for its comprehensive analysis, which can be further applied to the in-depth study of the complex microbiomes and contribute to the discovery of disease-associated bacteria.
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Focalização Isoelétrica/métodos , Neoplasias Pulmonares/microbiologia , Microbiota/imunologia , Saliva/microbiologia , Humanos , Saliva/citologiaRESUMO
Low-dimensional narrow-band-gap III-V semiconductors are key building blocks for the next generation of high-performance nanoelectronics, nanophotonics, and quantum devices. Realizing these various applications requires an efficient methodology that enables the material dimensional control during the synthesis process and the mass production of these materials with perfect crystallinity, reproducibility, low cost, and outstanding electronic and optoelectronic properties. Although advances in one- and two-dimensional narrow-band-gap III-V semiconductors synthesis, the progress toward reliable methods that can satisfy all of these requirements has been limited. Here, we demonstrate an approach that provides a precise control of the dimension of InAs from one-dimensional nanowires to wafer-scale free-standing two-dimensional nanosheets, which have a high degree of crystallinity and outstanding electrical and optical properties, using molecular-beam epitaxy by controlling catalyst alloy segregation. In our approach, two-dimensional InAs nanosheets can be obtained directly from one-dimensional InAs nanowires by silver-indium alloy segregation, which is much easier than the previously reported methods, such as the traditional buffering technique and select-area epitaxial growth. Detailed transmission electron microscopy investigations provide solid evidence that the catalyst alloy segregation is the origination of the InAs dimensional transformation from one-dimensional nanowires to two-dimensional nanosheets and even to three-dimensional complex crosses. Using this method, we find that the wafer-scale free-standing InAs nanosheets can be grown on various substrates including Si, MgO, sapphire, GaAs, etc. The InAs nanosheets grown at high temperature are pure-phase single crystals and have a high electron mobility and a long time-resolved terahertz kinetics lifetime. Our work will open up a conceptually new and general technology route toward the effective controlling of the dimension of the low-dimensional III-V semiconductors. It may also enable the low-cost fabrication of free-standing nanosheet-based devices on an industrial scale.
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PURPOSE: There was limited study available on successful intervention for central-line-associated bloodstream infection (CLABSI) done at nonintensive care unit (ICU) and resources-limited setting. The objective of this study was to design, implement and evaluate a strategy to reduce CLABSI rate in non-ICU settings at general medical wards of Hospital Tuanku Ja'afar Seremban. DESIGN/METHODOLOGY/APPROACH: Preinterventional study was conducted in one-month period of January 2019, followed by intervention period from February to March 2019. Postintervention study was conducted from April to July 2019. The CLABSI rates were compared between pre and postintervention periods. A multifaceted intervention bundle was implemented, which comprised (1) educational program for healthcare workers, (2) weekly audit and feedback and (3) implementation of central line bundle of care. FINDINGS: There was a significant overall reduction of CLABSI rate between preintervention and postintervention period [incidence rate ratio (IRR) of 0.06 (95 percent CI, 0.01-0.33; P = 0.001)]. PRACTICAL IMPLICATIONS: CLABSI rates were reduced by a multifaceted intervention bundle, even in non-ICU and resource-limited setting. This includes a preinterventional study to identify the risk factors followed by a local adaption of the recommended care bundles. This study recommends resources-limited hospitals to design a strategy that is suitable for their own local setting to reduce CLABSI. ORIGINALITY/VALUE: This study demonstrated the feasibility of a multifaceted intervention bundle that was locally adapted with an evidence-based approach to reduce CLABSI rate in non-ICU and resource-limited setting.
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Controle de Infecções/métodos , Pacotes de Assistência ao Paciente , Garantia da Qualidade dos Cuidados de Saúde , Sepse/prevenção & controle , Adulto , Catéteres/efeitos adversos , Prática Clínica Baseada em Evidências , Recursos em Saúde , Unidades Hospitalares , Humanos , Malásia/epidemiologiaRESUMO
BACKGROUND: The merging of two divergent genomes during hybridization can result in the remodeling of parental gene expression in hybrids. A molecular basis underling expression change in hybrid is regulatory divergence, which may change with the parental genetic divergence. However, there still no unanimous conclusion for this hypothesis. RESULTS: Three species of Camellia with a range of genetic divergence and their F1 hybrids were used to study the effect of parental genetic divergence on gene expression and regulatory patterns in hybrids by RNA-sequencing and allelic expression analysis. We found that though the proportion of differentially expressed genes (DEGs) between the hybrids and their parents did not increase, a greater proportion of DEGs would be non-additively (especially transgressively) expressed in the hybrids as genomes between the parents become more divergent. In addition, the proportion of genes with significant evidence of cis-regulatory divergence increased, whereas with trans-regulatory divergence decreased with parental genetic divergence. CONCLUSIONS: The discordance within hybrid would intensify as the parents become more divergent, manifesting as more DEGs would be non-additively expressed. Trans-regulatory divergence contributed more to the additively inherited genes than cis, however, its contribution to expression difference would be weakened as cis mutations accumulated over time; and this might be an important reason for that the more divergent the parents are, the greater proportion of DEGs would be non-additively expressed in hybrid.
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Camellia/genética , Perfilação da Expressão Gênica , Variação Genética , Hibridização Genética , Alelos , GenômicaRESUMO
Knowledge about the chemical composition of floral volatile organic compounds (VOCs) is valuable in biological studies as well as for the flavor, cosmetic, and fragrance industries. The flowers of Chinese chestnut (Castanea mollissima) emit a distinctive semen-like odor; however, the chemical composition and biological role for the semen-like odor of chestnut flowers remain scarcely studied. Herein, we report the floral VOCs and the pollinators of chestnut flowers. A fast method based on a neutral desorption (ND) device coupled to extractive atmospheric pressure chemical ionization mass spectrometry (EAPCI-MS) was developed for the rapid identification of VOCs from freshly collected chestnut flowers without any chemical pretreatment. Chemical identification was performed using high-resolution MS analysis in combination with tandem MS analysis and whenever possible was confirmed by the analysis of standard reference compounds. Twenty volatiles were identified, most of which are nitrogen-containing. Out of the identified volatiles, 1-pyrroline is known to have a semen-like odor and is probably also responsible for the semen-like odor of the chestnut flowers. Four nitrogenous VOCs of chestnut flowers, including 1-pyrroline, 1-piperideine, 2-pyrrolidone, and phenethylamine, were also common in other semen-like odor flowers such as Photinia serrulata, Castanopsis sclerophylla, and Stemona japonica, suggesting similar chemical origin. The main visitors of chestnut flowers were dipteran species, such as Eristalis tenax, Eristalis arvorum, Episyrphus balteatus, Lucilia sericata, Chrysomya megacephala, Chrysochus asclepiadeus, and Adalia bipunctata. Our results suggest that the chestnut flowers and other semen-like odor flowers may present a new type of sapromyophily. This study also indicates that ND-EAPCI-MS provides more sensitive and simpler detection of many VOCs (particularly nitrogen-containing VOCs) than GC-MS and therefore can be used to complement traditional approaches for the higher chemical coverage of VOCs analysis. Graphical abstract á .
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Fagaceae/química , Flores/química , Espectrometria de Massas/métodos , Odorantes/análise , Sêmen/química , Compostos Orgânicos Voláteis/análise , Pressão AtmosféricaRESUMO
We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction can be suppressed, and the spin-orbit interaction dominates spin state mixing. We observe dependence of the leakage current on the applied magnetic field direction and determine the direction of the spin-orbit interaction field. We show that the spin-orbit field lies in a direction perpendicular to the nanowire axis but with a pronounced off-substrate-plane angle. The results are expected to have an important implication in employing InAs nanowires to construct spin-orbit qubits and topological quantum devices.