Gold/graphene fractals as tunable plasmonic devices

Graphene, an atomically thin sheet of carbon atoms arranged in a honeycomb geometry, is attracting unique attention thanks to its extraordinary mechanical, electrical and optical properties. This thesis work concerns the realization of graphene-based nanoscale devices for novel plasmonic applications. We focus mainly on gold/graphene (Au/G) structures designed to display plasmonic multiresonances in the visible range thanks to the nanostructure geometry based on the Sierpinski carpet (SC) deterministic fractal

Harmine activates intrinsic and extrinsic pathways of apoptosis in B16F-10 melanoma

<p>Abstract</p> <p>Background</p> <p>Harmine is a beta-carboline alkaloid from the plant <it>Peganum harmala</it>. Previous studies found that harmine inhibited metastasis of B16F-10 melanoma cells. This study aims to elucidate the role of harmine in apoptosis of B16F-10 cells.</p> <p>Methods</p> <p>B16F-10 melanoma cells were treated in the presence and absence of harmine <it>in vitro</it>. Morphological changes, cell cycle and expression of various pro and anti- apoptotic genes were analyzed for the study of apoptosis.</p> <p>Results</p> <p>Morphological observation and DNA laddering assay showed that harmine treated cells displayed marked apoptotic characteristics, such as nuclear fragmentation, appearance of apoptotic bodies and DNA laddering fragment. TUNEL assay and flow cytometric analysis also confirmed apoptosis. Furthermore, RT-PCR analysis showed that harmine induced apoptosis in B16F-10 melanoma cells by up-regulating Bax and activating Caspase-3, 9 and p53 and down-regulating Bcl-2. Harmine also up-regulated Caspase-8 and Bid, indicating that harmine affected both extrinsic and intrinsic pathways of apoptosis. This study also showed inhibitory effects of harmine on some transcription factors and pro- inflammatory cytokines that protect cell from apoptosis.</p> <p>Conclusion</p> <p>Harmine activates both intrinsic and extrinsic pathways of apoptosis and regulates some transcription factors and pro-inflammatory cytokines.</p

Effect of Thermocycling on the Colour Stability of Aesthetic Restorative Materials: An in-vitro Spectrophotometric Analysis

Objective: To compare the color stability of Cention N, Fuji IX GP Extra, and Fuji IX GP after thermocycling. Material and Methods: Ten discs of each material of dimension 10 x 1 mm were prepared using a split mold. The preparations of the specimens were done according to the powder/liquid ratio as recommended by the manufacturers [4.6:1, 3.4:1 and 3.6:1 for the groups I, II, and III, respectively]. After setting, the samples were retrieved, and the thickness of each specimen was measured using a micrometer at five different locations. The specimens with variations in thickness, porosity or cracks were discarded and thus not included in the study. The selected specimens were stored in distilled water for 24 hours prior to testing. The prepared specimens were thermocycled at 5°C and 55°C, with a dwell time of 15 seconds for 250 or 500 cycles. Subsequently, the color parameters of the discs were measured using a spectrophotometer. The data were analyzed using two way ANOVA test, and a p-value &lt;0.001 was considered. Results: Thermocycling resulted in changes in the color of both Glass Ionomer cement and Cention N (p&lt;0.001). Among the materials tested, Cention N showed superior color stability. Conclusion: Cention N exhibited better color stability compared to Glass ionomer cements

Effect of Chelating Agents on Push-Out Bond Strength of NeoMTA Plus to Root Canal Dentin

Objective:&nbsp;To evaluate and compare the effect of 17% Ethylenediaminetetraacetic Acid (EDTA), 9% Etidronic acid (HEDP), and 7% Maleic acid (MA) on the push-out bond strength of NeoMTA Plus sealer to the coronal, middle, and apical thirds of root canal dentin.&nbsp;Material and Methods:&nbsp;Forty single-rooted human maxillary central incisors were selected and decoronated to 12 mm long root fragments. Working length was established and root canals were then enlarged up to rotary Protaper F3. After each instrumentation, the root canal was irrigated with 2.5% NaOCl. For the final irrigation regimen, the specimens were divided into 4 groups (n=10) and treated with EDTA, HEDP, MA or Saline. Root canals were coated with NeoMTA Plus sealer, and obturation was done with single cone obturation technique. Subsequently, three horizontal sections were taken from the coronal, middle and apical thirds of each specimen, and POBS was measured using a universal testing machine. The type of bond failures was assessed under a stereomicroscope. Statistical analysis was done with One-way ANOVA with Tukey’s Post hoc analysis.&nbsp;Results:&nbsp;MA and EDTA showed the highest POBS. There was no significant difference in bond strength between MA and EDTA (p&gt;0.05). HEDP and Saline showed lower POBS. Among all the four groups, the coronal third showed the highest values, followed by middle and apical thirds.&nbsp;Conclusion:&nbsp;The type of chelating agent used during the root canal treatment significantly affects the bond strength of NeoMTA Plus to the root canal dentin

Cloning, characterization and expression analysis of NBS-LRR-type resistance gene analogues (RGAs) in coconut

Coconut palms are highly susceptible to diseases caused by different pathogens, and replanting with resistant varieties is the best way to manage them. Obtaining a collection of resistance gene analogues (RGAs) is an effective strategy to identify genomic regions linked to disease resistance. We have successfully used a comparative genomics approach to amplify putative RGAs from the coconut root (wilt) disease resistant cultivar Chowghat Green Dwarf (CGD) by using primers designed based on conserved motifs of the NBS-LRR domain of the date palm. The amplified sequences were cloned, sequenced and characterized. The coconut RGAs had high identity to monocot NBS-LRRs. A complete structural analysis and 3-D modeling of the NBS domain of coconut RGA was also undertaken. Real-time quantitative polymerase chain reaction analysis indicated that the isolated coconut NBS-LRR class RGAs was expressed more in root (wilt) disease resistant genotypes than in susceptible ones. This study would provide a base for future efforts to map disease resistant traits in coconut

The 1-aminocyclopropane-1-carboxylic acid deaminase-producing Streptomyces violaceoruber UAE1 can provide protection from sudden decline syndrome on date palm

In the United Arab Emirates (UAE), sudden decline syndrome (SDS) is one of the major fungal diseases caused by Fusarium solani affecting date palm plantations. To minimize the impact of the causal agent of SDS on date palm, native actinobacterial strains isolated from rhizosphere soils of healthy date palm plants were characterized according to their antifungal activities against F. solani DSM 106836 (Fs). Based on their in vitro abilities, two promising biocontrol agents (BCAs), namely Streptomyces tendae UAE1 (St) andStreptomyces violaceoruber UAE1 (Sv), were selected for the production of antifungal compounds and cell wall degrading enzymes (CWDEs), albeit their variations in synthesizing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD). Although both isolates showed antagonism when applied 7 days before the pathogen in the greenhouse experiments, the ACCD-producing Sv was relatively superior in its efficacy against SDS over the non-ACCD-producing St. This was evident from the symptoms of SDS in diseased date palm seedlings which were greatly reduced by Sv compared to St. On a scale of 5.0, the estimated disease severity indices in Fs-diseased seedlings were significantly (P < 0.05) reduced from 4.8 to 1.5 and 0.5 by St and Sv, respectively. Thus, the number of conidia of Fs recovered from plants pre-treated with both BCAs was comparable, but significantly (P < 0.05) reduced compared to plants without any BCA treatment. In addition, a significant (P < 0.05) decrease in ACC levels of both the root and shoot tissues was detected inSv + Fs seedlings to almost similar levels of healthy seedlings. However, in planta ACC levels highly increased in seedlings grown in soils infested with the pathogen alone or amended with St prior to F. solani infestation (St + Fs). This suggests a major role of ACCD production in relieving the stress of date palm seedlings infected with F. solani, thus supporting the integrated preventive disease management programs against this pathogen. This is the first report of effective rhizosphere actinobacterial BCAs to provide protection against SDS on date palm, and to help increase agricultural productivity in a more sustainable manner in the UAE and the other arid regions

Neuropeptides in the Antennal Lobe of the Yellow Fever Mosquito, Aedes aegypti.

For many insects, including mosquitoes, olfaction is the dominant modality regulating their behavioral repertoire. Many neurochemicals modulate olfactory information in the central nervous system, including the primary olfactory center of insects, the antennal lobe. The most diverse and versatile neurochemicals in the insect nervous system are found in the neuropeptides. In the present study, we analyzed neuropeptides in the antennal lobe of the yellow fever mosquito, Aedes aegypti, a major vector of arboviral diseases. Direct tissue profiling of the antennal lobe by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry indicated the presence of 28 mature products from 10 different neuropeptide genes. In addition, immunocytochemical techniques were used to describe the cellular location of the products of up to seven of these genes within the antennal lobe. Allatostatin A, allatotropin, SIFamide, FMRFamide-related peptides, short neuropeptide F, myoinhibitory peptide, and tachykinin-related peptides were found to be expressed in local interneurons and extrinsic neurons of the antennal lobe. Building on these results, we discuss the possible role of neuropeptide signaling in the antennal lobe of Ae. aegypti. J. Comp. Neurol. 522:592-608, 2014. (c) 2013 Wiley Periodicals, Inc

Factors associated with unfavourable outcomes in COVID-19 patients with acute kidney injury: A single centre retrospective observational study

Background: COVID-19 infection adversely affects all nephron segments to cause acute kidney injury (AKI), leading to greater mortality. Methods: A retrospective analysis was conducted of patients (age &gt;18 years) with COVID-19-related AKI admitted at a quaternary-level multispeciality hospital between September 2020 and April 2021. Data regarding various clinical, radiological, biochemical and haematological parameters were analysed and their association with clinical outcomes concerning mortality or survival was determined. Results: We included 67 patients (46 males) with a mean age of 68.2 ± 12.17 years, of whom 45 patients were haemodynamically unstable, and 52 had hypoxaemia at the time of presentation. Overall, 53% of the cases were discharged from the hospital and 46% succumbed to the illness; females had higher mortality (67%, P = 0.024). The mean neutrophil/lymphocyte ratio (P = 0.014), HbA1c (P = 0.011), LDH (P = 0.002), D-dimer (P = 0.034) and C-reactive protein (P = 0.001) levels at admission were higher in patients with unfavourable outcomes. Increased mortality was present in patients who had a higher clinical category of illness (P = 0.014), advanced AKI stage (P = 0.001), haemodynamic instability at presentation (P &lt; 0.001), required some form of KRT (P = 0.009), oxygen (P = 0.047), ventilatory (P = 0.028) or inotropic support (P = &lt;0.001), were on calcium channel blockers at the time of admission (P = 0.024) or required antifungal agents (P = 0.003) or insulin therapy (P = 0.041). Conclusions: Female COVID-19 patients with AKI, presenting with advanced disease and chest pain, having preexisting comorbidities, had increased mortality

Graphene Plasmonic Fractal Metamaterials for Broadband Photodetectors

Metamaterials have recently established a new paradigm for enhanced light absorption in state-of-the-art photodetectors. Here, we demonstrate broadband, highly efficient, polarization-insensitive, and gate-tunable photodetection at room temperature in a novel metadevice based on gold/graphene Sierpinski carpet plasmonic fractals. We observed an unprecedented internal quantum efficiency up to 100% from the near-infrared to the visible range with an upper bound of optical detectivity of 1011 Jones and a gain up to 106, which is a fingerprint of multiple hot carriers photogenerated in graphene. Also, we show a 100-fold enhanced photodetection due to highly focused (up to a record factor of |E/E0| ≈ 20 for graphene) electromagnetic fields induced by electrically tunable multimodal plasmons, spatially localized in self-similar fashion on the metasurface. Our findings give direct insight into the physical processes governing graphene plasmonic fractal metamaterials. The proposed structure represents a promising route for the realization of a broadband, compact, and active platform for future optoelectronic devices including multiband bio/chemical and light sensors