A comprehensive understanding of the combined effects of surface roughness and wettability on the dynamics of the trapping process is lacking. This can be primarily attributed to the contradictory ...experimental and numerical results regarding the impact of wettability on the capillary trapping efficiency. The discrepancy is presumably caused by the surface roughness of the inner pore‐solid interface. Herein, we present a comparative μ‐CT study of the static fluid‐fluid pattern in porous media with smooth (glass beads) and rough surfaces (natural sands). For the first time, a global optimization method was applied to map the characteristic geometrical and morphological properties of natural sands to 2‐D micromodels that exhibit different degrees of surface roughness. A realistic wetting model that describes the apparent contact angle of the rough surface as a function surface morphology and the intrinsic contact angle was also proposed. The dynamics of the trapping processes were studied via visualization micromodel experiments. Our results revealed that sand and glass beads displayed opposite trends in terms of the contact angle dependence between 5° and 115°. Sand depicted a nonmonotonous functional contact angle dependency, that is, a transition from maximal trapping to no trapping, followed by an increase to medium trapping. In contrast, glass beads showed a sharp transition from no trapping to maximal trapping. Since both porous media exhibit similar morphological properties (similar Minkowski functions: porosity, surface density, mean curvature density, Euler number density), we deduce that this difference in behavior is caused by the difference in surface roughness that allows complete wetting and hence precursor thick‐film flow for natural sands. Experimental results on micromodels verified this hypothesis.
Key Points
Wettability, surface roughness, and pore space structure have an impact on trapping efficiency
Porous media with rough surface, as natural sands and glass‐ceramic micromodels, were studied
Wettability‐controlled crossover from snap‐off to by‐pass trapping and spontaneous precursor thick‐film flow were observed
Innovative techniques, such as environmental DNA (eDNA) metabarcoding, are now promoting broader biodiversity monitoring at unprecedented scales, because of the reduction in time, presumably lower ...cost, and methodological efficiency. Our goal was to assess the efficiency of established inventory techniques (live-trapping grids, pitfall traps, camera trapping, mist netting) as well as eDNA for detecting Amazonian mammals. For terrestrial small mammals, we used 32 live-trapping grids based on Sherman and Tomahawk traps (total effort of 10,368 trap-nights); in addition to 16 pitfall traps (1,408 trap-nights). For bats, we used mist nets at 8 sites (4,800 net hours). For medium and large mammals, we used 72 camera trap stations (5,208 camera-days). We identified vertebrate and mammal taxa based on eDNA analysis (12S region, with V05 and Mamm01 markers) from water samples, including a total of 11 3-km transects for stagnant water sampling and seven small streams for running water sampling. A total of 106 mammal species were recorded. Building on sample-based rarefaction and extrapolation curves, both trapping grids and pitfall were successful, recording 91.16% and 82.1% of the expected species for these techniques (~22 and ~9 species), and 16.98% and 6.60% of the total recorded mammal species, respectively. Mist nets recorded 83.2% of the expected bat species (~48), and 34.91% of the total recorded species. Camera trapping recorded 99.2% of the predicted large- and medium-sized species (~31), and 33.02% of the total recorded species. eDNA recorded 75.4% of the expected mammal species for this technique (~68), and 47.0% of the total recorded species. eDNA resulted in a useful tool that saves on effort and reduces sampling costs. This study is among the first to show the large potential of eDNA metabarcoding for assessing Amazonian mammal communities, providing, in combination with conventional techniques, a rapid overview of mammal diversity with broad applications to monitoring, management and conservation. By including appropriate genetic markers and updated reference databases, eDNA metabarcoding method can be extended to the whole vertebrate community.
The perturbation in the environment by the discharge of toxic dyes in wastewater is a matter of concern and there is an urgent need to impart the balance. These organic dyes can be removed via ...catalytic degradation, adsorption or membrane filtration. In this study, we have developed a Zn(II)-based coordination polymer (CP) Zn(bpyp)(HL-NO2)2n(1) by solvothermal method using 2,5-bis(pyrid-4-yl)pyridine (bpyp) and 4-nitrobenzoic acid (HL-NO2) as organic linkers. The single crystal X-ray diffraction depicts that the Zn(II) adopts a tetragonal coordination environment and 1D linear chains are linked together to form a 2D framework via hydrogen bonding and π-π interactions. Methyl orange (MO), methyl violet (MV), methyl blue (MB) and rhodamine B (RhB) were investigated for photocatalytic degradation in the presence of visible light. Synthesized 1 shows 82% degradation of RhB dye. The Hirshfeld surfaces study demonstrated that these synthesized coordination polymers contain various forms of intermolecular contacts (C⋯C, H⋯C, H⋯H, and O⋯H).
The degradation efficiency of organic dye by 1 was discussed. The active species involved in the degradation of Rh B has been assessed using trapping experiments. Display omitted
•Zn(bpyp)(HL-NO2)2n(1) were synthesized.•The degradation efficiency of RhB by 1 was very high compared to other dye.•The active species involved in the degradation of Rh B has been assessed using trapping experiments.•Hirsfeld dnorm surface of carboxylate are mainly covered by H⋯O/O⋯H, C⋯H/H⋯C and H⋯H interactions.
Laser cooling and trapping
, and magneto-optical trapping methods in particular
, have enabled groundbreaking advances in science, including Bose-Einstein condensation
, quantum computation with ...neutral atoms
and high-precision optical clocks
. Recently, magneto-optical traps (MOTs) of diatomic molecules have been demonstrated
, providing access to research in quantum simulation
and searches for physics beyond the standard model
. Compared with diatomic molecules, polyatomic molecules have distinct rotational and vibrational degrees of freedom that promise a variety of transformational possibilities. For example, ultracold polyatomic molecules would be uniquely suited to applications in quantum computation and simulation
, ultracold collisions
, quantum chemistry
and beyond-the-standard-model searches
. However, the complexity of these molecules has so far precluded the realization of MOTs for polyatomic species. Here we demonstrate magneto-optical trapping of a polyatomic molecule, calcium monohydroxide (CaOH). After trapping, the molecules are laser cooled in a blue-detuned optical molasses to a temperature of 110 μK, which is below the Doppler cooling limit. The temperatures and densities achieved here make CaOH a viable candidate for a wide variety of quantum science applications, including quantum simulation and computation using optical tweezer arrays
. This work also suggests that laser cooling and magneto-optical trapping of many other polyatomic species
will be both feasible and practical.
There is keen interest in the use of amorphous WO3 thin films as cathodic electrodes in transmittance-modulating electrochromic devices1–4. However, these films suer from ion-trapping-induced ...degradation of optical modulation and reversibility on extended LiC-ion exchange. Here,we demonstrate that ion-trapping-induced degradation, which is commonly believed to be irreversible, can be successfully eliminatedby constant-current-driven de-trapping; that is, WO3 films can be rejuvenated and regain their initial highly reversible electrochromic performance. Pronounced ion trapping occurs when x exceeds 0.65 in LixWO3 during ion insertion. We find two main kinds of Li+-ion-trapping site (intermediate and deep) in WO3, where the intermediate ones are most prevalent. Li+ ions can be completely removed from intermediate traps but are irreversibly bound in deep traps. Our results provide a general framework for developing and designing superior electrochromic materials and devices.
Summary
Camera trapping is a widely applied method to study mammalian biodiversity and is still gaining popularity. It can quickly generate large amounts of data which need to be managed in an ...efficient and transparent way that links data acquisition with analytical tools.
We describe the free and open‐source R package camtrapR, a new toolbox for flexible and efficient management of data generated in camera trap‐based wildlife studies. The package implements a complete workflow for processing camera trapping data. It assists in image organization, species and individual identification, data extraction from images, tabulation and visualization of results and export of data for subsequent analyses. There is no limitation to the number of images stored in this data management system; the system is portable and compatible across operating systems.
The functions provide extensive automation to minimize data entry mistakes and, apart from species and individual identification, require minimal manual user input. Species and individual identification are performed outside the R environment, either via tags assigned in dedicated image management software or by moving images into species directories.
Input for occupancy and (spatial) capture–recapture analyses for density and abundance estimation, for example in the R packages unmarked or secr, is computed in a flexible and reproducible manner. In addition, survey summary reports can be generated, spatial distributions of records can be plotted and exported to gis software, and single‐ and two‐species activity patterns can be visualized.
camtrapR allows for streamlined and flexible camera trap data management and should be most useful to researchers and practitioners who regularly handle large amounts of camera trapping data.
Optical tweezers, a simple and robust implementation of optical micromanipulation technologies, have become a standard tool in biological, medical and physics research laboratories. Recently, with ...the utilization of holographic beam shaping techniques, more sophisticated trapping configurations have been realized to overcome current challenges in applications. Holographically generated higher‐order light modes, for example, can induce highly structured and ordered three‐dimensional optical potential landscapes with promising applications in optically guided assembly, transfer of orbital angular momentum, or acceleration of particles along defined trajectories. The non‐diffracting property of particular light modes enables the optical manipulation in multiple planes or the creation of axially extended particle structures. Alongside with these concepts which rely on direct interaction of the light field with particles, two promising adjacent approaches tackle fundamental limitations by utilizing non‐optical forces which are, however, induced by optical light fields. Optoelectronic tweezers take advantage of dielectrophoretic forces for adaptive and flexible, massively parallel trapping. Photophoretic trapping makes use of thermal forces and by this means is perfectly suited for trapping absorbing particles. Hence the possibility to tailor light fields holographically, combined with the complementary dielectrophoretic and photophoretic trapping provides a holistic approach to the majority of optical micromanipulation scenarios.
Optical tweezers, a simple and robust implementation of optical micromanipulation technologies, have become a standard tool in biological, medical and physics research laboratories. Recently, with the utilization of holographic beam shaping techniques, more sophisticated trapping configurations have been realized to overcome current challenges in applications. Holographically generated higher‐order light modes, for example, can induce highly structured and ordered three‐dimensional optical potential landscapes with promising applications in optically guided assembly, transfer of orbital angular momentum, or acceleration of particles along defined trajectories. The non‐diffracting property of particular light modes enables the optical manipulation in multiple planes or the creation of axially extended particle structures. Alongside with these concepts which rely on direct interaction of the light field with particles, two promising adjacent approaches tackle fundamental limitations by utilizing non‐optical forces which are, however, induced by optical light fields. Optoelectronic tweezers take advantage of dielectrophoretic forces for adaptive and flexible, massively parallel trapping. Photophoretic trapping makes use of thermal forces and by this means is perfectly suited for trapping absorbing particles. Hence the possibility to tailor light fields holographically, combined with the complementary dielectrophoretic and photophoretic trapping provides a holistic approach to the majority of optical micromanipulation scenarios.
High‐fidelity trapping of mitochondrial dynamic activity is critical to value cellular functions and forecast disease but lack of spatial–temporal probes. Given that commercial mitochondria probes ...suffering from low photostability, aggregation‐caused quenching effect, and limited signal‐to‐noise ratio from fluorescence “always on” in the process of targeting mitochondria, here, the rational design strategy of a novel aggregation‐induced emission (AIE) molecular motif and unique insight into the high‐fidelity targeting of mitochondria is reported, thereby illustrating the relationship between tailoring molecular aggregation state and mitochondrial targeting ability. This study focuses on how to exactly modulate the hydrophilicity and the aggregated state for realizing “off‐on” fluorescence, as well as matching the charge density to go across the cell membrane for mitochondrial targeting. Probe tricyano‐methylene‐pyridine (TCM‐1) exhibits an unprecedented high‐fidelity feedback on spatial–temporal mitochondrial information with several advantages such as “off‐on” near‐infrared characteristic, high targeting capacity, favorable biocompatibility, as well as excellent photostability. TCM‐1 also produces reactive oxygen species in situ for image‐guided photodynamic anticancer therapy. Through unraveling the relationship between tuning molecular aggregation behavior and organelle‐specific targeting ability, for the first time, a unique guide is provided in designing AIE‐active probes to explore the hydrophilicity and membrane potential for targeting subcellular organelles.
A novel aggregation‐induced emission building block is connected with a triphenylphosphine group at substitution positions for the high‐fidelity targeting of mitochondria, where the molecular aggregation state is modulated for realizing the “off‐on” characteristic, and the charge density is matched for mitochondrial targeting. The report reveals the relationship between tuning molecular aggregation behavior and organelle‐specific targeting ability.
We propose a systematic design of protograph-based quasi-cyclic (QC) low-density parity-check (LDPC) codes with low error floor. We first characterize the trapping sets of such codes and demonstrate, ...using edge coloring techniques, that the QC structure of the code eliminates some of the trapping set structures that can exist in a code with the same degree distribution and girth but lacking the QC structure. Based on this characterization, our design aims at eliminating a targeted collection of trapping sets. Considering the parent/child relationship between the trapping sets in the collection, we search for and eliminate those trapping sets that are in the collection but are not a child of any other trapping set in the collection. An efficient layered algorithm is designed for the search of these targeted trapping sets. Compared to the existing codes in the literature, the designed codes are superior in the sense that they are free of the same collection of trapping sets while having a smaller block length, or a larger collection of trapping sets while having the same block length. In addition, the efficiency of the search algorithm makes it possible to design codes with larger degrees which are free of trapping sets within larger ranges compared to the state-of-the-art.
The front cover artwork is provided by Prof. Sang‐Hyun Oh's group at the University of Minnesota. The image shows the optical trapping of chiral nanoparticles using coaxial nano‐optical tweezers, ...devices capable of harnessing light to manipulate objects a few nanometers in size. Read the full text of the Review at 10.1002/cphc.202100004.
“The theory behind optical tweezers is presented and discussed along with the various techniques and instrumentation used for the realization of optical tweezing down to the nanometer scale…” This and more about the story behind the front cover can be found in the Review at 10.1002/cphc.202100004.
PDF
