Interannual variability and decadal stability of benthic organisms on an Indonesian coral reef

The availability of colonizable substrate is an important driver of the temporal dynamics of sessile invertebrates on coral reefs. Increased dominance of algae and, in some cases, sponges has been documented on many coral reefs around the world, but how these organisms benefit from non-colonized substrate on the reef is unclear. In this study, we described the temporal dynamics of benthic organisms on an Indonesian coral reef across two time periods between 2006 and 2017 (2006–2008 and 2014–2017), and investigated the effects of colonizable substrate on benthic cover of coral reef organisms at subsequent sampling events. In contrast with other Indonesian reefs where corals have been declining, corals were dominant and stable over time at this location (mean ± SE percentage cover 42.7 ± 1.9%). Percentage cover of turf algae and sponges showed larger interannual variability than corals and crustose coralline algae (CCA) (P < 0.001), indicating that these groups are more dynamic over short temporal scales. Bare substrate was a good predictor of turf cover in the following year (mean effect 0.2, 95% CI: 0–0.4). Algal cover combined with bare space was a good predictor of CCA cover the following year generally, and of sponge cover the following year but only at one of the three sites. These results indicate that turf algae on some Indonesian reefs can rapidly occupy free space when this becomes available, and that other benthic groups are probably not limited by the availability of bare substrate, but may overgrow already fouled substrates.

Origin of Large Bumps Abnormally Grown on 4H-SiC Epitaxial Film by Adding HCl Gas with High Cl/Si Ratio in CVD Process

4H-SiC homo-epitaxial film was grown by adding HCl gas with a high Cl/Si ratio in CVD process, and defect formation and origin of the defect were investigated by confocal differential interference contrast (CDIC) microscope, PL imaging and normal differential interference contrast (DIC) microscope. It was found that a large number of large bumps are formed on the film grown at a high Cl/Si ratio of 30, and a large number of PL defects on bare substrate before the film growth are also observed. Coordinates where the bumps on the film are observed were good agreement with those where the PL defects on the bare substrate are observed. An etch pit sample on reproduced substrate from which epitaxial film was removed was fabricated by etching process using molten KOH+Na2O2, and some types of etch pits which might be originated from threading edge dislocations (TEDs), threading screw dislocations (TSDs) and basal plane dislocations (BPDs) in the substrate were observed. The coordinates where the etch pits on the reproduced substrate are observed were also good agreement with those where the bumps on the epitaxial film are observed. Therefore, it was clarified that a large number of the bumps abnormally grown on the epitaxial film are originated from the dislocations in the substrate.

Six-fold plasmonic enhancement of thermal scavenging via CsPbBr3 anti-Stokes photoluminescence

One-photon up-conversion, also called anti-Stokes photoluminescence (ASPL), is the process whereby photoexcited carriers scavenge thermal energy and are promoted into a higher energy excited state before emitting a photon of greater energy than initially absorbed. Here, we examine how ASPL from CsPbBr3 nanoparticles is modified by coupling with plasmonically active gold nanoparticles deposited on a substrate. Two coupling regimes are examined using confocal fluorescence microscopy: three to four Au nanoparticles per diffraction limited region and monolayer Au nanoparticle coverage of the substrate. In both regimes, CsPbBr3 ASPL is blue-shifted relative to CsPbBr3 deposited on a bare substrate, corresponding to an increase in the thermal energy scavenged per emitted photon. However, with monolayer Au nanoparticle coverage, ASPL is enhanced relative to the conventional Stokes-shifted PL. Together, these phenomena result in a 6.7-fold increase in the amount of thermal energy extracted from the system during optical absorption and reemission.

Morphology and Electrochemical Characterization of Electrodeposited Nanocrystalline Ni-Co Electrodes for Methanol Fuel Cells

An electrocatalytic electrode surface was developed for alcoholic fuel cell by electrodeposition of Ni-Co alloy on a 301 stainless steel substrate. Material characterization by EDX and XRD confirmed deposition of Ni-Co alloy on stainless steel surfaces with a cobalt content of 15–35%. SEM showed nodular and/or angular particles with some subparticles embedded within the coarse nodules. Increasing the deposition current density as well as deposition time leads to deposition of Ni-Co alloys characterized by coarse angular morphology with lower cobalt content. The electrocatalytic activity of the coated electrodes was characterized by potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) tests in anodic solution for electrochemical oxidation of methanol. Polarization study showed very much higher current density for the coated electrode compared to bare stainless steel. According to the EIS test in 1 M methyl alcohol acidic solution, it was found that polarization resistance of the coated sample was much lower compared to the bare substrate. The electrical equivalent circuit at the metal solution interface was found to be matching Randle with Warburg resistance. The results of the CV test showed higher peaks for alcohol oxidation and oxygen reduction compared to the bare substrate. The alloy coating with increased effective surface area leads to enhancement in the electrocatalytic activity of the electrodes. The alloys deposited at current densities of 50 and 80 mA/cm2 for 30 minutes (15–16% Co) had higher catalytic activity of the Ni-Co nanocrystalline deposits for methanol oxidation for direct methanol fuel cells, than those under other deposition conditions.

Study on Magnetic and Corrosion Properties of Ce16Fe95-xCoxB8 (x=0-4) Alloys

To understand the phase composition and improve the magnetic performances of Ce2Fe14B-type alloys, the ribbons of Ce16Fe95-xCoxB8(x=0-4.0) were prepared by melt-spinning at a quench wheel velocity of 40 m/s. The phase composition and magnetic properties of Ce16Fe95-xCoxB8(x=0-4.0) alloys were investigated. XRD results indicated that the main phase existed in the as-spun ribbons is Ce2Fe14B. The amorphous formation ability and thermal stability of as-spun ribbons were enhanced by trace cobalt addition. Co-doped samples had higher Curie temperature compared with bare Ce2Fe14B, which signified that Co atoms could substitute for Fe directly into Ce2Fe14B phase. The corrosion potential of alloys from-1089mV (vs. SCE) to-1077mV (vs. SCE) which indicated that the Co-doped provided better corrosion protection properties for the Ce-Fe-B magnet compared with bare substrate.

Facilitation shifts paradigms and can amplify coastal restoration efforts

Restoration has been elevated as an important strategy to reverse the decline of coastal wetlands worldwide. Current practice in restoration science emphasizes minimizing competition between out-planted propagules to maximize planting success. This paradigm persists despite the fact that foundational theory in ecology demonstrates that positive species interactions are key to organism success under high physical stress, such as recolonization of bare substrate. As evidence of how entrenched this restoration paradigm is, our survey of 25 restoration organizations in 14 states in the United States revealed that >95% of these agencies assume minimizing negative interactions (i.e., competition) between outplants will maximize propagule growth. Restoration experiments in both Western and Eastern Atlantic salt marshes demonstrate, however, that a simple change in planting configuration (placing propagules next to, rather than at a distance from, each other) results in harnessing facilitation and increased yields by 107% on average. Thus, small adjustments in restoration design may catalyze untapped positive species interactions, resulting in significantly higher restoration success with no added cost. As positive interactions between organisms commonly occur in coastal ecosystems (especially in more physically stressful areas like uncolonized substrate) and conservation resources are limited, transformation of the coastal restoration paradigm to incorporate facilitation theory may enhance conservation efforts, shoreline defense, and provisioning of ecosystem services such as fisheries production.

Preparation of a native β-cyclodextrin modified plasmonic hydrogel substrate and its use as a surface-enhanced Raman scattering scaffold for antibiotics identification

Native β-cyclodextrin modified Ag-hydrogel was synthesized as a SERS sensor for the determination of antibiotics with a poor affinity to the bare substrate.

The Effect of Deposition Time on the Structural Properties of ZnO Nanorods Prepared by Sol-Gel Immersion Method

ZnO nanorods were successfully grown on Au coated Si substrate and Si bare substrate. The growth was using sol-gel immersion method at different deposition time which is 2, 4, 6, 8, 10 and 12 hours. In the presence of Au, growth rate of nanorods is much faster as it performs as a catalyst by decreasing the growth time of ZnO nanorods to half compared to growth on Si substrate without Au coated. Using Scanning Electron Microscope (SEM), changes in growth of nanorods at different deposition time was captured and the structural properties are discussed.

Adhesion ofE. coliBacteria Cells to Prosthodontic Alloys Surfaces Modified by TiO2Sol-Gel Coatings

The evaluation of the degree of bacteriaE. coliadhesion to modified surfaces of the chosen prosthodontic alloys was presented. The study was carried out on Co-Cr (Wironit), Ni-Cr (Fantocer), and Fe-Cr-Ni (Magnum AN) alloys. Bare substrate as a control and titanium dioxide coated samples were used. The samples were placed for 24 hours in bacterial culture medium. After incubation period, a number of bacterial cells were evaluated by scanning electron microscope. The study revealed that modification of the alloy surfaces by titanium dioxide coating significantly decreases the amount of bacteria adhering to the surfaces and that additionally bare metal alloy substrates have a different degree of susceptibility to bacterial adhesion.