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Abstract Microfluidics has enabled the miniaturization of fluidic systems for various biomedical and industrial applications, including small-scale robotic propulsion. One mechanism for generating propulsive force through microfluidics is by exploiting the solutal Marangoni effect via releasing surfactant on the air-water interface. Surfactants locally reduce the surface tension, which leads to a surface stress that can propel the floating robot, called Marangoni surfer. However, so far the release of the surfactant is not controllable. In this study, we combine microfluidics-based Marangoni propulsion with a novel untethered magnetic pumping mechanism to enhance its controllability. The proposed magnetic micropump capitalizes on the interaction force between two soft magnets, which can generate a pumping force of 4.64 mN to actuate a membrane, and achieve a deformation of 450 μm. Net flow is achieved using a nozzle/diffuser flow rectifier whose efficacy as a function of the channel geometry is numerically studied. We investigate the flow rate of the pump with regard to the actuation frequency. Finally, we demonstrate its ability to control the motion of the Marangoni surfer.

Abstract High-dimensional quantum entanglement is a cornerstone for advanced technology enabling large-scale noise-tolerant quantum systems, fault-tolerant quantum computing, and distributed quantum networks. The recently developed biphoton frequency comb (BFC) provides a powerful platform for high-dimensional quantum information processing in its spectral and temporal quantum modes. Here we propose and generate a singly-filtered high-dimensional BFC via spontaneous parametric down-conversion by spectrally shaping only the signal photons with a Fabry-Pérot cavity. High-dimensional energy-time entanglement is verified through Franson-interference recurrences and temporal correlation with low-jitter detectors. Frequency- and temporal- entanglement of our singly-filtered BFC is then quantified by Schmidt mode decomposition. Subsequently, we distribute the high-dimensional singly-filtered BFC state over a 10 km fiber link with a post-distribution time-bin dimension lower bounded to be at least 168. Our demonstrations of high-dimensional entanglement and entanglement distribution show the singly-filtered quantum frequency comb’s capability for high-efficiency quantum information processing and high-capacity quantum networks.

Summary: Microorganism communities can shape host phenotype evolution but are often comprised of thousands of taxa with varied impact on hosts. Identification of taxa influencing host evolution relies on first describing microorganism communities and acquisition routes. Keratinolytic (keratin-degrading) microorganisms are hypothesized to be abundant in saltmarsh sediments and to contribute to plumage evolution in saltmarsh-adapted sparrows. Metabarcoding was used to describe plumage bacterial (16S rRNA) and fungal (ITS) communities in three sparrow species endemic to North America’s Atlantic coast saltmarshes. Results describe limited within-species variability and moderate host species-level patterns in microorganism diversity and community composition. A small percentage of overall microorganism diversity was comprised of potentially keratinolytic microorganisms, warranting further functional studies. Distinctions between plumage and saltmarsh sediment bacteria, but not fungal, communities were detected, suggesting multiple bacterial acquisition routes and/or vertebrate host specialization. This research lays groundwork for future testing of causal links between microorganisms and avian host evolution.

Untethered microrobotic grasping has enabled the precise manipulation of small components in difficult‐to‐reach environments. However, the fabrication of deformable grasping robots at small scales requires advanced materials and fabrication technologies. Alternatively, multiple microrobots can be used to surround and grasp objects. By collaborating, microrobots can perform complex tasks that they would not be capable of executing individually. The complexity of controlling multiple untethered microrobots has limited the applications of collaborative microrobots to two‐dimensional operations. To fill this gap, this work proposes a collaborative microrobotic system for three‐dimensional grasping operations. The system is based on the control of two magnetic agents and the exploitation of the magnetic interactions between them to grasp, manipulate, and assemble passive components. A custom‐made closed‐loop controller is developed to automatically stabilize the system, achieving pose control of a grasped passive component (of 2 mm in size) with a precision of 300 μm in position and 10° in orientation. The main advantage of the proposed system is its capability to reconfigure the magnetic agents for other operations, as demonstrated by the assembly of a microgear and subsequent reconfiguration to power the assembled mechanism.

An integrated thin-film lithium niobate phase modulator enables on-chip frequency and bandwidth control of single photons

Abstract Magnetocapillary interactions between particles allow to self-assemble floating crystals along liquid interfaces. For a fixed number of particles, different states possessing different symmetrical features, known as metastable states, coexist. In this paper, we demonstrate how to trigger the transition from one state to another, either by rearranging the crystal, or by controlling its growth. First, we show that externally controlled magnetic fields can squeeze the entire crystal to induce structural modifications, that upon relaxation can lead to a modified state. Second, we propose localized laser-induced thermocapillary flows that can be used to guide new particles towards an existing crystal in a desired direction, thus favoring a particular resulting state. The control of the formation of metastable states is a key ingredient to functionalize such assemblies, paving the way to self-assembled microrobots.

Abstract Qudit entanglement is an indispensable resource for quantum information processing since increasing dimensionality provides a pathway to higher capacity and increased noise resilience in quantum communications, and cluster-state quantum computations. In continuous-variable time–frequency entanglement, encoding multiple qubits per photon is only limited by the frequency correlation bandwidth and detection timing jitter. Here, we focus on the discrete-variable time–frequency entanglement in a biphoton frequency comb (BFC), generating by filtering the signal and idler outputs with a fiber Fabry–Pérot cavity with 45.32 GHz free-spectral range (FSR) and 1.56 GHz full-width-at-half-maximum (FWHM) from a continuous-wave (cw)-pumped type-II spontaneous parametric downconverter (SPDC). We generate a BFC whose time-binned/frequency-binned Hilbert space dimensionality is at least 324, based on the assumption of a pure state. Such BFC’s dimensionality doubles up to 648, after combining with its post-selected polarization entanglement, indicating a potential 6.28 bits/photon classical-information capacity. The BFC exhibits recurring Hong–Ou–Mandel (HOM) dips over 61 time bins with a maximum visibility of 98.4% without correction for accidental coincidences. In a post-selected measurement, it violates the Clauser–Horne–Shimony–Holt (CHSH) inequality for polarization entanglement by up to 18.5 standard deviations with an S-parameter of up to 2.771. It has Franson interference recurrences in 16 time bins with a maximum visibility of 96.1% without correction for accidental coincidences. From the zeroth- to the third-order Franson interference, we infer an entanglement of formation (E of) up to 1.89 ± 0.03 ebits—where 2 ebits is the maximal entanglement for a 4 × 4 dimensional biphoton—as a lower bound on the 61 time-bin BFC’s high-dimensional entanglement. To further characterize time-binned/frequency-binned BFCs we obtain Schmidt mode decompositions of BFCs generated using cavities with 45.32, 15.15, and 5.03 GHz FSRs. These decompositions confirm the time–frequency scaling from Fourier-transform duality. Moreover, we present the theory of conjugate Franson interferometry—because it is characterized by the state’s joint-temporal intensity (JTI)—which can further help to distinguish between pure-state BFC and mixed state entangled frequency pairs, although the experimental implementation is challenging and not yet available. In summary, our BFC serves as a platform for high-dimensional quantum information processing and high-dimensional quantum key distribution (QKD).

Abstract Deterministic frequency manipulation of single photons is an essential tool for quantum communications and quantum networks. We demonstrate a 15.65 GHz frequency shift for classical and nonclassical light using a commercially available quadrature phase-shift keying modulator. The measured spectrum of frequency-shifted single photons indicates a high carrier-to-sideband ratio of 30 dB. We illustrate our frequency shifter’s utility in quantum photonics by performing Hong–Ou–Mandel quantum interference between two photons whose initial frequency spectra overlap only partially, and showing visibility improvement from 62.7 to 89.1% after one of the photons undergoes a corrective frequency shift.

Non-line-of-sight imaging is typically limited by loss of directional information due to diffuse reflections scattering light in all directions. Here, the authors see around corners by using vertical edges and temporal response to pulsed light to obtain angular and longitudinal resolution, respectively.

La calidad del agua subterránea en estado natural está relacionada con las propiedades del suelo a través del cual fluye. El arsénico (As) es un elemento que resulta nocivo para la salud, tanto en concentraciones altas como en ingesta crónica en bajas concentra ciones. En esta investigación se estudiaron muestras de aguas subterráneas de la ciudad de Rafaela y Sunchales, las que poseen valores de arsénico superiores al límite establecido por el Código Alimentario Argentino (CAA). En la adsorción se utiliza un sólido para eliminar sustancias disueltas del agua. Con el fin de remover el As, se estudiaron diferentes adsorbentes tales como zeolita, bentonita, arcilla de La Rioja, suelo arcillo limoso de Santa Fe y arcilla de Misiones. Por su efectividad, se seleccionó la arcilla de Misiones y se trabajó con una columna compuesta por ésta y por arenas de filtración, obteniéndose una remoción de As aproximadamente de un 80 %.

Active optical imaging systems use their own light sources to recover scene information but typically operate with large number of photon detections. Here, the authors present a 3D imaging system that acquires depth and reflectivity information with a single photon camera operating in low-light conditions.

Photonic integrated circuits provide a compact and stable platform for quantum photonics. Here we demonstrate a silicon photonics quantum key distribution (QKD) encoder in the first high-speed polarization-based QKD field tests. The systems reach composable secret key rates of 1.039 Mbps in a local test (on a 103.6-m fiber with a total emulated loss of 9.2 dB) and 157 kbps in an intercity metropolitan test (on a 43-km fiber with 16.4 dB loss). Our results represent the highest secret key generation rate for polarization-based QKD experiments at a standard telecom wavelength and demonstrate photonic integrated circuits as a promising, scalable resource for future formation of metropolitan quantum-secure communications networks.

A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as a mobile phase comprised of acetonitrile-0.1 M KH2PO4 pH 6.5–0.1 M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59 v/v/v/v) delivered at a flow rate of 1.0 mL/min. The stationary phase consisted of reverse-phase XTerra® (250 mm × 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50%–150% (r2 = 0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg), respectively, with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation.

The functional principle behind extrusion‐based printing is the capability of flowing material through a nozzle on demand, which must solidify upon deposition, a behavior exhibited only by some materials. Embedded printing offers a solution to maintain shape fidelity during the deposition of a wider range of materials. However, the use of a moving nozzle in a support bath can lead to bath disturbance and the spreading of the ink. In this study, a novel embedded printing technique that eliminates the need for a nozzle by employing a magnetic sphere as the plotting moiety is introduced. The externally steered sphere creates a path by locally fluidizing the bath, allowing the simultaneously injected ink to flow into the space behind it. The method is benchmarked using water as an ink, achieving free‐form printing without additional stabilization methods. The creation of solid structures is also demonstrated by printing a photocurable ink that is crosslinked and removed from the bath. Moreover, the plotting magnet can be incorporated into the printed part during the crosslinking, thus giving place to a magnetically responsive structure. This advancement paves the way for innovations in fields such as tissue engineering and microrobotics by enabling the fabrication of intricate and functional designs. [ABSTRACT FROM AUTHOR]

Introduction: The use of veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) as a direct bridge to heart transplantation (BTT) is not common in adults worldwide. BTT with ECMO is associated with increased early/mid‐term mortality compared with other interventions. In low‐ and middle‐income countries (LMIC), where no other type of short‐term mechanical circulatory support is available, its use is widespread and increasingly used as rescue therapy in patients with cardiogenic shock (CS) as a direct bridge to heart transplantation (HT). Objective: To assess the outcomes of adult patients using VA‐ECMO as a direct BTT in an LMIC and compare them with international registries. Methods: We conducted a single‐center study analyzing consecutive adult patients requiring VA‐ECMO as BTT due to refractory CS or cardiac arrest (CA) in a cardiovascular center in Argentina between January 2014 and December 2022. Survival and adverse clinical events after VA‐ECMO implantation were evaluated. Results: Of 86 VA‐ECMO, 22 (25.5%) were implanted as initial BTT strategy, and 52.1% of them underwent HT. Mean age was 46 years (SD 12); 59% were male. ECMO was indicated in 81% for CS, and the most common underlying condition was coronary artery disease (31.8%). Overall, in‐hospital mortality for VA‐ECMO as BTT was 50%. Survival to discharge was 83% in those who underwent HT and 10% in those who did not, p <.001. In those who did not undergo HT, the main cause of death was hemorrhagic complications (44%), followed by thrombotic complications (33%). The median duration of VA‐ECMO was 6 days (IQR 3‐16). There were no differences in the number of days on ECMO between those who received a transplant and those who did not. In the Spanish registry, in‐hospital survival after HT was 66.7%; the United Network of Organ Sharing registry estimated post‐transplant survival at 73.1% ± 4.4%, and in the French national registry 1‐year posttransplant survival was 70% in the VA‐ECMO group. Conclusions: In adult patients with cardiogenic shock, VA‐ECMO as a direct BTT allowed successful HT in half of the patients. HT provided a survival benefit in listed patients on VA‐ECMO. We present a single center experience with results comparable to those of international registries. [ABSTRACT FROM AUTHOR]

In this work we performed a detailed numerical analysis to investigate the static and dynamic magnetic properties of hexagonal cells of square and circular cobalt nanodots as a function of the distance between them and the external magnetic field to which they are subjected. By simulating hysteresis curves with the external magnetic field applied parallel and perpendicular to the plane of these nanostructures, we can conclude that the cobalt nanodots presented a significant perpendicular magnetic anisotropy. We also obtained that the coercivity increases with decreasing volume, which implies that the circular dots have a higher coercivity than the square dots. Furthermore, we studied the dynamic susceptibility of these systems and found that it is possible to control both the position and the number of resonance peaks by controlling the geometry and the distance between the magnetic nanodots. This work provides useful information on the behaviour of cobalt nanodot arrays, opening paths for the design and improvement of two-dimensional technological devices. [ABSTRACT FROM AUTHOR]

Untethered microrobotic grasping has enabled the precise manipulation of small components in difficult‐to‐reach environments. However, the fabrication of deformable grasping robots at small scales requires advanced materials and fabrication technologies. Alternatively, multiple microrobots can be used to surround and grasp objects. By collaborating, microrobots can perform complex tasks that they would not be capable of executing individually. The complexity of controlling multiple untethered microrobots has limited the applications of collaborative microrobots to two‐dimensional operations. To fill this gap, this work proposes a collaborative microrobotic system for three‐dimensional grasping operations. The system is based on the control of two magnetic agents and the exploitation of the magnetic interactions between them to grasp, manipulate, and assemble passive components. A custom‐made closed‐loop controller is developed to automatically stabilize the system, achieving pose control of a grasped passive component (of 2 mm in size) with a precision of 300 μm in position and 10° in orientation. The main advantage of the proposed system is its capability to reconfigure the magnetic agents for other operations, as demonstrated by the assembly of a microgear and subsequent reconfiguration to power the assembled mechanism. [ABSTRACT FROM AUTHOR]