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BACKGROUND: Until now, the analysis of microvascular networks in the reperfused ischemic brain has been limited due to tissue transparency challenges. METHODS: Using light sheet microscopy, we assessed microvascular network remodeling in the striatum from 3 hours to 56 days post-ischemia in 2 mouse models of transient middle cerebral artery occlusion lasting 20 or 40 minutes, resulting in mild ischemic brain injury or brain infarction, respectively. We also examined the effect of a clinically applicable S1P (sphingosine-1-phosphate) analog, FTY720 (fingolimod), on microvascular network remodeling. RESULTS: Over 56 days, we observed progressive microvascular degeneration in the reperfused striatum, that is, the lesion core, which was followed by robust angiogenesis after mild ischemic injury induced by 20-minute middle cerebral artery occlusion. However, more severe ischemic injury elicited by 40-minute middle cerebral artery occlusion resulted in incomplete microvascular remodeling. In both cases, microvascular networks did not return to their preischemic state but displayed a chronically altered pattern characterized by higher branching point density, shorter branches, higher unconnected branch density, and lower tortuosity, indicating enhanced network connectivity. FTY720 effectively increased microvascular length density, branching point density, and volume density in both models, indicating an angiogenic effect of this drug. CONCLUSIONS: Utilizing light sheet microscopy together with automated image analysis, we characterized microvascular remodeling in the ischemic lesion core in unprecedented detail. This technology will significantly advance our understanding of microvascular restorative processes and pave the way for novel treatment developments in the stroke field.
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Isquemia Encefálica , Cloridrato de Fingolimode , Camundongos , Animais , Cloridrato de Fingolimode/farmacologia , Cloridrato de Fingolimode/uso terapêutico , Infarto da Artéria Cerebral Média/patologia , Microscopia , Encéfalo/irrigação sanguínea , Microvasos/patologia , Modelos Animais de DoençasRESUMO
Deep learning methods have emerged as powerful tools for analyzing histopathological images, but current methods are often specialized for specific domains and software environments, and few open-source options exist for deploying models in an interactive interface. Experimenting with different deep learning approaches typically requires switching software libraries and reprocessing data, reducing the feasibility and practicality of experimenting with new architectures. We developed a flexible deep learning library for histopathology called Slideflow, a package which supports a broad array of deep learning methods for digital pathology and includes a fast whole-slide interface for deploying trained models. Slideflow includes unique tools for whole-slide image data processing, efficient stain normalization and augmentation, weakly-supervised whole-slide classification, uncertainty quantification, feature generation, feature space analysis, and explainability. Whole-slide image processing is highly optimized, enabling whole-slide tile extraction at 40x magnification in 2.5 s per slide. The framework-agnostic data processing pipeline enables rapid experimentation with new methods built with either Tensorflow or PyTorch, and the graphical user interface supports real-time visualization of slides, predictions, heatmaps, and feature space characteristics on a variety of hardware devices, including ARM-based devices such as the Raspberry Pi.
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Aprendizado Profundo , Software , Computadores , Processamento de Imagem Assistida por Computador/métodosRESUMO
We propose a concise hardware architecture supporting efficient exclusive OR (XOR) and exclusive NOR (XNOR) operations, by employing a single photonic spiking neuron based on a passive add-drop microring resonator (ADMRR). The threshold mechanism and inhibitory dynamics of the ADMRR-based spiking neuron are numerically discussed on the basis of the coupled mode theory. It is shown that a precise XOR operation in the ADMRR-based spiking neuron can be implemented by adjusting temporal differences within the inhibitory window. Additionally, within the same framework, the XNOR function can also be carried out by accumulating the input power over time to trigger an excitatory behavior. This work presents a novel, to the best of our knowledge, and pragmatic technique for optical neuromorphic computing and information processing utilizing passive devices.
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Natural products have been an important source of therapeutic agents and chemical tools. The recent realization that many natural product biosynthetic genes are silent or sparingly expressed during standard laboratory growth has prompted efforts to investigate their regulation and develop methods to induce their expression. Because it is difficult to intuit signals that induce a given biosynthetic locus, we recently implemented a forward chemical-genetic approach to identify such inducers. In the current work, we applied this approach to nine silent biosynthetic loci in the model bacterium Burkholderia thailandensis to systematically screen for elicitors from a library of Food and Drug Administration-approved drugs. We find that ß-lactams, fluoroquinolones, antifungals, and, surprisingly, calcimimetics, phenothiazine antipsychotics, and polyaromatic antidepressants are the most effective global inducers of biosynthetic genes. Investigations into the mechanism of stimulation of the silent virulence factor malleicyprol by the ß-lactam piperacillin allowed us to elucidate the underlying regulatory circuits. Low-dose piperacillin causes oxidative stress, thereby inducing redox-sensing transcriptional regulators, which activate malR, a pathway-specific positive regulator of the malleicyprol gene cluster. Malleicyprol is thus part of the OxyR and SoxR regulons in B. thailandensis, allowing the bacterium to initiate virulence in response to oxidative stress. Our work catalogs a diverse array of elicitors and a previously unknown regulatory input for secondary metabolism in B. thailandensis.
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Vias Biossintéticas , Burkholderia/fisiologia , Estresse Oxidativo , Piperacilina/farmacologia , Fatores de Virulência/biossíntese , Antibiose/efeitos dos fármacos , Vias Biossintéticas/efeitos dos fármacos , Burkholderia/efeitos dos fármacos , Burkholderia/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Modelos Biológicos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Metabolismo Secundário/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , beta-Lactamas/farmacologiaRESUMO
Aromatic amines are important commercial chemicals, but their carcinogenicity poses a threat to humans and other organisms, making their rapid quantitative detection increasingly urgent. Here, amorphous MoO3 (a-MoO3) monolayers with localized surface plasmon resonance (LSPR) effect in the visible region are designed for the trace detection of carcinogenic aromatic amine molecules. The hot-electron fast decay component of a-MoO3 decreases from 301â fs to 150â fs after absorption with methyl orange (MO) molecules, indicating the plasmon-induced hot-electron transfer (PIHET) process from a-MoO3 to MO. Therefore, a-MoO3 monolayers present high SERS performance due to the synergistic effect of electromagnetic enhancement (EM) and PIHET, proposing the EM-PIHET synergistic mechanism in a-MoO3. In addition, a-MoO3 possesses higher electron delocalization and electronic state density than crystal MoO3 (c-MoO3), which is conducive to the PIHET. The limit of detection (LOD) for o-aminoazotoluene (o-AAT) is 10-9â M with good uniformity, acid resistance, and thermal stability. In this work, trace detection and identification of various carcinogenic aromatic amines based on a-MoO3 monolayers is realized, which is of great significance for reducing cancer infection rates.
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The regulatory mechanisms that link WRKY gene expression to fruit ripening are largely unknown. Using transgenic approaches, we showed that a WRKY gene from wild strawberry (Fragaria vesca), FvWRKY48, may be involved in fruit softening and ripening. We showed that FvWRKY48 is localized to the nucleus and that degradation of the pectin cell wall polymer homogalacturonan, which is present in the middle lamella and tricellular junction zones of the fruit, was greater in FvWRKY48-OE (overexpressing) fruits than in empty vector (EV)-transformed fruits and less substantial in FvWRKY48-RNAi (RNA interference) fruits. Transcriptomic analysis indicated that the expression of pectate lyase A (FvPLA) was significantly downregulated in the FvWRKY48-RNAi receptacle. We determined that FvWRKY48 bound to the FvPLA promoter via a W-box element through yeast one-hybrid, electrophoretic mobility shift, and chromatin immunoprecipitation quantitative polymerase chain reaction experiments, and ß-glucosidase activity assays suggested that this binding promotes pectate lyase activity. In addition, softening and pectin degradation were more intense in FvPLA-OE fruit than in EV fruit, and the middle lamella and tricellular junction zones were denser in FvPLA-RNAi fruit than in EV fruit. We speculated that FvWRKY48 maybe increase the expression of FvPLA, resulting in pectin degradation and fruit softening.
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Fragaria , Parede Celular/genética , Parede Celular/metabolismo , Fragaria/genética , Fragaria/metabolismo , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Pectinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Polissacarídeo-LiasesRESUMO
We propose and demonstrate an all-optical synaptic neuron based on an add-drop microring resonator (ADMRR) with power-tunable auxiliary light. Dual neural dynamics of passive ADMRRs, having spiking response and synaptic plasticity, are numerically investigated. It is demonstrated that, by injecting two beams of power-tunable and opposite-direction continuous light into an ADMRR and maintaining their sum power at a constant value, linear-tunable and single-wavelength neural spikes can be flexibly generated, in virtue of the nonlinear effects triggered by perturbation pulses. Based on this, a weighting operation system based on cascaded ADMRRs is designed; it enables implementation of real-time weighting operations at a number of wavelengths. This work provides a novel, to the best of our knowledge, approach for integrated photonic neuromorphic systems based entirely on optical passive devices.
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Dispositivos Ópticos , Fótons , Óptica e Fotônica , NeurôniosRESUMO
Graphite carbon nitride (g-C3N4) with a suitable structure and strong amine activity is designed and prepared to serve as a hydrogen bond donor for the microfibrilization of corncob cellulose to form a cellulose microfiber (CMF) bundle. Simultaneously, well-dispersed nanosized g-C3N4 is loaded into the bundle to form a photocatalyst for efficient photodegradation of rhodamine B (Rh B) in water. Under the optimal preparation conditions at 165 °C, 10 min, and 0.08 mol/L H2SO4, the yield of g-C3N4-functionalized cellulose microfibers (CMF-g-C3N4) reaches to the highest over 70%. The catalytic rate of CMF-g-C3N4 is 3.3 times larger than that of pure g-C3N4. The degradation rate of Rh B is maintained at over 90% in 10 cycles of photocatalytic degradation. The obtained CMF-g-C3N4 also has good thermal stability and mechanical properties. This research suggests a particularly simple way to transform cellulose into a highly efficient photocatalyst for water treatment.
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Keratitis caused by drug-resistant bacteria is a severe condition that can lead to corneal perforation and even blindness, making effective treatment a top priority amid growing antibiotic resistance. Eye drops for anti-inflammatory treatment necessitate frequent administration of high doses throughout every day due to bacterial resistance resulting from antibiotic overuse and the low bioavailability of drugs. To overcome these issues, an antibacterial nanocomposite is prepared via conjugating random copolymers of galactose and 3-(acrylamide)phenylboronic acid to the surface of silver nanoparticles. The customized nanocomposites trigger specific binding to bacteria, resulting in excellent retention of the drug on the ocular surface, resulting in rapid and powerful killing of bacteria and inhibition of bacterial proliferation. Due to its superior drug delivery capabilities to the ocular surface, the functionalized nanocomplex markedly amplifies the anti-inflammatory efficacy, even at low doses. This effect is achieved by impeding immune cell infiltration and diminishing the synthesis of inflammatory mediators and cytokines, thereby suggesting enhanced healing properties for corneal inflammation. This study demonstrates a promising nanocomposite which is an effective and safe antibacterial strategy for bacterial keratitis with favorable prognostic and clinical conversion potential.
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Ceratite , Nanopartículas Metálicas , Humanos , Prata/farmacologia , Prata/química , Preparações Farmacêuticas , Nanopartículas Metálicas/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antibacterianos/química , Ceratite/tratamento farmacológico , Ceratite/microbiologia , Bactérias , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêuticoRESUMO
Narrowband deep blue thermally activated delayed fluorescent (TADF) materials have attracted significant attention. Herein, four asymmetrical structured TADF emitters based on diphenylsulfone (DPS) acceptor and 9,9-dimethyl-9,10-dihydroacridine (DMAC) donor with progressive performances were developed. The tert-butyloxy auxiliary electron-donor was adopted to restrict the intramolecular rotations and provide efficient steric hindrance. Regioisomerization by altering the substitution position of DMAC on DPS unit further enhanced the intra- and inter-molecular interactions. The accompanying effects yielded increased energy level, minimized reorganization energy, and inhibited non-radiative transitions in the crystals of tBuO-SOmAD, which achieved narrowband deep-blue emission peaking at 424â nm (FWHM=64â nm, ΦF =33.6 %) through aggregation-induced, blue-shifted emission (AIBSE). In addition, deep-blue organic light emitting diodes (OLEDs) based on tBuO-SOmAD realized the electroluminescence (EL) spectrum peaking located at 435â nm and CIE coordination of (0.12, 0.09).
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The high activation barrier, inferior rate performance, and short cycling life severely constrain the practical applications of the high-capacity Li2 S cathode. Herein, we fabricate a Li2 S-Cu nanocomposite with a drastically reduced activation potential, fast rate capability, and extraordinary cycling stability even under a practically relevant areal capacity of 2.96â mAh cm-2 . Detailed experimental investigations aided by theoretical calculations indicate that instead of converting to S8 via troublesome soluble lithium polysulfides, Li2 S is thermodynamically and kinetically more favorable to react with Cu by the displacement reaction, which alters the redox couple from Li2 S/S to Cu/Cu2 S, leading to the excellent electrochemical performance. Moreover, the stability of the composite is demonstrated in the full-cell configuration consisting of commercial graphite anodes. This work provides an innovative and effective approach to realize highly activated and stable Li2 S cathode materials.
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BACKGROUND: Racial and ethnic minority children with cancer disproportionately receive intensive care at the end of life (EOL). It is not known whether these differences are goal-concordant or disparities. The authors sought to explore patterns of pediatric palliative care (PPC) and health care utilization in pediatric oncology patients receiving subspecialty palliative care at the end-of-life (last 6 months) and to examine goal-concordance of location of death in a subset of these patients. METHODS: This was a retrospective cohort study of pediatric oncology patients receiving subspecialty palliative care at a single large tertiary care center who died between January 2013 and March 2017. RESULTS: A total of 115 patients including 71 White, non-Hispanic patients and 44 non-White patients (including 12 Black patients and 21 Hispanic patients) were included in the analytic cohort. There were no significant differences in oncologic diagnosis, cause of death, or health care utilization in the last 6 months of life. White and non-White patients had similar PPC utilization including time from initial consult to death and median number of PPC encounters. Non-White patients were significantly more likely to die in the hospital compared to White patients (68% vs 46%, P = .03). Analysis of a subcohort with documented preferences (n = 45) revealed that 91% of White patients and 93% of non-White patients died in their preferred location of death. CONCLUSIONS: Although non-White children with cancer were more likely to die in the hospital, this difference was goal-concordant in our cohort. Subspecialty PPC access may contribute to the achievement of goal-concordant EOL care.
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Neoplasias , Assistência Terminal , Criança , Morte , Etnicidade , Objetivos , Humanos , Grupos Minoritários , Neoplasias/terapia , Cuidados Paliativos , Estudos RetrospectivosRESUMO
Optical devices like virtual reality (VR) headsets present challenges in terms of vergence-accommodation conflict that leads to visual fatigue for the user over time. Lenses available to meet these challenges include liquid crystal (LC) lenses, which possess a response time in the millisecond range. This response time is slow, while accessing multiple focal lengths. A ferroelectric liquid crystal (FLC) has a response time in the microsecond range. In this article, we disclose a switchable lens device having a combination of the fast FLC-based polarization rotation unit and a passive polarization-dependent LC lens. A cascaded combination of three such lens units allows access to eight different focal points quite rapidly and can be a convenient device for VR applications.
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BACKGROUND: Modern therapeutic advances in high-risk neuroblastoma have improved overall survival (OS), but it is unclear whether these survival gains have been equitable. This study examined the relationship between socioeconomic status (SES) and overall survival (OS) in children with high-risk neuroblastoma and whether SES-associated disparities have changed over time. PROCEDURE: In this population-based cohort study, children <18 years diagnosed with high-risk neuroblastoma (diagnosis at age ≥12 months with metastatic disease) from 1991 to 2015 were identified through the National Cancer Institute's Surveillance, Epidemiology, and End Results database. Associations of county-level SES variables and OS were tested with univariate Cox proportional hazards regression. For a subcohort diagnosed after 2007, insurance status was examined as an individual-level SES variable. Multivariable regression analyses with treatment era and interaction terms were performed when SES variables reached near-significance (p ≤ .1) in univariate and bivariate modeling with treatment era. RESULTS: Among 1217 children, 2-year OS improved from 53.0 ± 3.4% in 1991-1998 to 76.9 ± 2.9% in 2011-2015 (p < .001). In univariate analyses, children in high-poverty counties (hazard ratio [HR] = 1.74, 95% confidence interval [CI] = 1.17-2.60, p = .007), and those with Medicaid (HR = 1.40, 95% CI = 1.05-1.86, p = .02) experienced an increased hazard of death. No interactions between treatment era and SES variables were statistically significant in multivariable analyses, indicating that differences in the OS between SES groups did not change over time. CONCLUSIONS: Survival disparities among children with high-risk neuroblastoma have not widened over time, suggesting equitable access to and benefit from therapeutic advances. However, children of low SES experience persistently inferior survival. Interventions to narrow this disparity are paramount.
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Disparidades em Assistência à Saúde , Neuroblastoma , Classe Social , Fatores Socioeconômicos , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Humanos , Lactente , Cobertura do Seguro , Neuroblastoma/terapia , Pobreza , Estados Unidos/epidemiologiaRESUMO
The expression of membrane type-1 matrix metalloproteinase (MT1-MMP) in cancer cells is critical for understanding the development, invasion and metastasis of cancers. In this study, we devised an interference-free surface-enhanced Raman scattering (SERS) nanoprobe with high selectivity and specificity for MT1-MMP. The nanoprobe was comprised of silver core-silica shell nanoparticle with a Raman reporter tag (4-mercaptobenzonitrile) embedded in the interface. Moreover, the nitrile group in 4-mercaptobenzonitrile shows a unique characteristic peak in the Raman-silent region (1800-2800 cm-1), which eliminates spectral overlapping or background interference in the Raman fingerprint region (500-1800 cm-1). After surface modification with a targeting peptide, the nanoprobe allowed visualization and evaluation of MT1-MMP in breast cancer cells via SERS spectrometry. This interference-free, peptide-functionalized SERS nanoprobe is supposed to be conducive to early diagnosis and invasive assessment of cancer in clinical settings.
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Neoplasias da Mama/metabolismo , Metaloproteinase 14 da Matriz/metabolismo , Nanopartículas Metálicas/química , Imagem Molecular/métodos , Análise Espectral Raman/métodos , Neoplasias da Mama/diagnóstico , Linhagem Celular Tumoral , Feminino , Humanos , Sondas Moleculares/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Prata/químicaRESUMO
The practical implementation of lithium-sulfur batteries is obstructed by poor conductivity, sluggish redox kinetics, the shuttle effect, large volume variation, and low areal loading of sulfur electrodes. Now, amorphous N-doped carbon/MoS3 (NC/MoS3 ) nanoboxes with hollow porous architectures have been meticulously designed as an advanced sulfur host. Benefiting from the enhanced conductivity by the N-doped carbon, reduced shuttle effect by the strong chemical interaction between unsaturated Mo and lithium polysulfides, improved redox reaction kinetics by the catalytic effect of MoS3 , great tolerance of volume variation and high sulfur loading arising from flexible amorphous materials with hollow-porous structures, the amorphous NC/MoS3 nanoboxes enabled sulfur electrodes to deliver a high areal capacity with superior rate capacity and decent cycling stability. The synthetic strategy can be generalized to fabricate other amorphous metal sulfide nanoboxes.
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Transplantation-associated thrombotic microangiopathy (TA-TMA) is a known complication of autologous hematopoietic cell transplantation (aHCT), particularly in children with neuroblastoma. We describe a pediatric single-institution experience of TA-TMA after aHCT. Data were abstracted from the medical record of patients who underwent aHCT between January 1, 2008, and July 1, 2018, at Boston Children's Hospital. TA-TMA was diagnosed using either the International Working Group criteria or the "probable TA-TMA criteria" of Cho et al. Overall, 318 aHCTs were performed in 243 patients. Nine patients (3.7%) were diagnosed with TA-TMA. TA-TMA occurred most frequently in children with neuroblastoma (nâ¯=â¯7; 78%), all of whom were conditioned with carboplatin, etoposide, and melphalan. The median age at aHCT in children who developed TA-TMA was 3 years, 5 months (range, 18 months to 25 years). TMA was diagnosed at a median of 35 days (range, 8 to 106 days) after stem cell infusion. On a retrospective chart review using the same criteria used by the provider, patients met criteria a median of 5 days before the clinical diagnosis (range, 0 to 58 days). Eight patients had renal involvement at presentation, including nephrotic range proteinuria and severe hypertension, requiring from 2 to 6 antihypertensive medications. Two patients presented with multiorgan failure. Six patients were treated with eculizumab a median of 0 days after TA-TMA diagnosis (range, 0 to 11 days). On retrospective review, patients were treated a median of 18 days (range, 0 to 58 days) after meeting criteria for TA-TMA. Before initiation of therapy, 4 of 6 patients checked for serum complement levels had normal values, 1 had elevated CH50 and 1 had elevated sC59-b and CH50. All patients had CH50 levels within the target range (≤3 CAE) after induction therapy. Two patients (33%) had no response to eculizumab and died of multiorgan failure. The other 4 had both a hematologic response with transfusion independence (median, 6.5 weeks; range, 4 to 9 weeks) and renal response, defined as resolution of nephrotic range proteinuria (median, 21 weeks; range, 13 to 25 weeks). Among the eculizumab-treated survivors, 2 patients remained on prolonged eculizumab therapy, and one had recurrence of TA-TMA after discontinuation of eculizumab. All 4 eculizumab treated survivors have persistent organ dysfunction. Three children were treated with supportive care only; 2 died of relapsed cancer, and the third is alive with stage 2 chronic kidney disease. The median duration of follow-up after TA-TMA diagnosis was 2.5 years (range, 9 months to 4 years). The 1-year overall survival was 78% (SEâ¯=â¯14%). However, regardless of treatment, no survivors had complete normalization of function in all organs. Three children with normal serum CH50 and sc5b-9 levels responded to eculizumab. This report highlights the importance of maintaining a high suspicion for TA-TMA after aHCT. Further study is warranted to identify individual risk factors for TMA after aHCT, predict the response to eculizumab, and capture long-term sequelae in survivors.
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Anticorpos Monoclonais Humanizados/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Microangiopatias Trombóticas/etiologia , Adolescente , Adulto , Anticorpos Monoclonais Humanizados/uso terapêutico , Criança , Pré-Escolar , Inativadores do Complemento/efeitos adversos , Humanos , Lactente , Insuficiência de Múltiplos Órgãos/induzido quimicamente , Insuficiência de Múltiplos Órgãos/etiologia , Pediatria , Estudos Retrospectivos , Transplante Autólogo/efeitos adversos , Adulto JovemRESUMO
An alternative solution to the cyclical development of new antibiotics is the concept of disarming pathogens without affecting their growth, thereby eliminating the selective pressures that lead to resistant phenotypes. Here, we have employed our previously developed HiTES methodology to identify one such compound against the ESKAPE pathogen Pseudomonas aeruginosa. Rather than induce silent biosynthetic gene clusters, we used HiTES to suppress actively expressed virulence genes. By screening a library of 770 FDA-approved drugs, we identified guanfacine, a clinical hypertension drug, as an antivirulence agent in P.â aeruginosa. Follow-up studies showed that guanfacine reduces biofilm formation and pyocycanin production without altering growth. Moreover, we identified a homologue of QseC, a sensor His kinase used by multiple pathogens to turn on virulence, as a target of guanfacine. Our studies suggest that guanfacine might be an attractive antivirulence lead in P.â aeruginosa and provide a template for uncovering such molecules by screening for downregulators of actively expressed biosynthetic genes.
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Antibacterianos/farmacologia , Anti-Hipertensivos/farmacologia , Guanfacina/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Fatores de Virulência/antagonistas & inibidores , Antibacterianos/química , Anti-Hipertensivos/química , Guanfacina/química , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Inert dielectric shells coating the surface of metallic nanoparticles (NPs) are important for enhancing the NPs' stability, biocompatibility, and realizing targeting detection, but they impair NPs' sensing ability due to the electric fields damping. The dielectric shell not only determines the distance of the analyte from the NP surface, but also affects the field decay. From a practical point of view, it is extremely important to investigate the critical thickness of the shell, beyond which the NPs are no longer able to effectively detect the analytes. The plasmon decay length of the shell-coated NPs determines the critical thickness of the coating layer. Extracting from the exponential fitting results, we quantitatively demonstrate that the critical thickness of the shell exhibits a linear dependence on the NP volume and the dielectric constants of the shell and the surrounding medium, but only with a small variation influenced by the NP shape where the dipole resonance is dominated. We show the critical thickness increases with enlarging the NP sizes, or increasing the dielectric constant differences between the shell and surrounding medium. The findings are essential for applications of shell-coated NPs in plasmonic sensing.
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Glucocorticoid receptors (GRs) exert actions on the hippocampus that are important for memory formation. There are correlations between vascular dysfunctions and GR-related gene expression. Both vascular dysfunction and GR gene expression decline occur during the ageing process. Therefore, hypotensors, which have effects on improving vascular dysfunction, may be able to ameliorate GR gene expression decline in ageing mice and improve ageing-mediated memory deficits. In this study, we hypothesized that hypotensors could alleviate the decline of GR gene expression and ameliorate age-induced learning and memory deficits in a D-gal-induced ageing mice model. In line with our hypothesis, we found that chronic D-gal treatment decreased GR and DCX expression in the hippocampus, leading to learning and memory deficits. Amlodipine (AM) and puerarin (PU) treatment improved GR gene expression decline in the hippocampus and ameliorated the learning and memory deficits of D-gal-treated mice. These changes correlated with enhanced DCX expression and brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Furthermore, PU treatment conveyed better effects than AM treatment, but combination therapy did not enhance the effects on improving GR expression. However, we did not find evidence of these changes in non-D-gal-treated mice that lacked GR gene expression decline. These results suggest that AM and PU could improve D-gal-induced behavioural deficits in correlation with GR gene expression.