Browse Articles

Development and evaluation of a mechanical chest compression device for standardized rodent cardiopulmonary resuscitation

Abstract Small animal models are indispensable in cardiopulmonary resuscitation (CPR) research. High-quality CPR, characterized by consistent chest compression rate, depth, and positioning is crucial for survival. However, achieving standardization in manual high-frequency chest compressions in small animal models remains technically challenging. This study evaluated the reproducibility of manual chest compressions and introduced a novel mechanical chest compression device (MCD) designed to improve consistency in rodent experiments. In an in vitro setup, manual compressions were performed by ten participants at target rates ranging from 100 to 260 bpm, guided by a metronome. Compressions performed on a fluid-filled polymer reservoir were analyzed for the compression rate, variability, and time within a ± 10% target range. A color indicator was used to assess the variability of the compression point. A small animal MCD was designed and tested under the same conditions. In vivo, 5 Sprague-Dawley rats underwent 5 min of electrically induced normothermic cardiac arrest followed by 8 min of external chest compressions using the MCD. Obtained data was compared to the in vitro results. A total of 21,650 manual and 20,098 mechanical compressions were analyzed. At 200 bpm, chest compressions using the MCD were significantly more precise (201 ± 1.2 bpm) than manual compressions (218 ± 21 bpm, p  < 0.001) with a significant reduced compression point variability (1.7 ± 0.1 cm 2 vs. 10.8 ± 3.1 cm 2 , p  < 0.001). Manual compressions maintained target rate in 58.8% of time compared to 100% for the MCD. In vivo testing confirmed these findings with chest compressions remaining within the target range 100% of the time and showing minimal rate variability (1.8 ± 1.7 bpm). These results highlight the limitations of manual chest compressions and demonstrate the potential of the MCD to enhance standardization and reproducibility in rodent CPR research.

Difluorinative Cyclopropene Rearrangement by I(I)/I(III) Catalysis: Regio‐ and Stereoselective Synthesis of Allyl Difluorides

Abstract Allyl difluorides are pervasive in the pharmaceutical arena, but synthetic challenges in the construction of highly substituted derivatives impede chemical space exploration. Consequently, efforts to develop general approaches that display high levels of regio‐ and stereo‐selectivity continue to be intensively pursued. To contribute to this vibrant area of contemporary organofluorine chemistry, a highly efficient difluorinative rearrangement of densely substituted cyclopropenes is disclosed under the auspices of I(I)/I(III) catalysis. This platform leverages a highly intuitive ring opening model that enables di‐, tri‐, and tetra‐substituted allyl difluorides to be generated with high levels of stereoselectivity where the transient I(III) center serves as a traceless directing group. X‐ray crystal structural analysis is described together with facile post‐reaction modifications that include expedient access to fluorinated indenes. Given the ubiquity of the allyl difluoride chemotype in drug discovery, it is envisaged that this operationally simple, organocatalytic platform will expedite bioisostere design.

Seasonal monopolization of small carrion by a scarab beetle in terra firme Amazonian rainforests

Heterogeneity of active mast cells, endothelial cells, and fibroblasts in hemophilic arthritis defined by synovial single-cell sequencing

Palladium‐Catalyzed Enantioselective Three‐Component Dearomative Coupling of Bromoarenes: Modular Construction of Terpenoid Scaffolds

Abstract We report a palladium‐catalyzed asymmetric three‐component coupling of bromoarenes, diazoalkanes, and malonates. It represents a significant advancement in catalytic enantioselective dearomative 1,4‐difunctionalization of unactivated arenes. A palladium catalyst of a novel phosphoramidite enables a domino reaction consisting of enantiofacial aryl insertion of a bound diazoalkane and regioselective and stereospecific allylic substitution. The new reaction was readily applied in short total syntheses of three terpenoids, including (+)‐erogorgiaene, (−)‐7‐hydroxy‐3,4‐dihydrocadalin, and (−)‐odongrossin C. Mechanistic studies establish that stereocontrol arises from a concerted aryl migration/N 2 extrusion, which forms the key cyclic π‐allyl palladium intermediate. The C4‐regioselectivity of the malonate attack is governed by a combination of ligand effects, silyl group sterics, and stabilizing noncovalent interactions between the naphthyl ring and sodium malonate.

A global perspective on cold wave disasters

Optimization and kinetic modeling of ciprofloxacin adsorption and photocatalytic degradation in water

Abstract The persistent presence of pharmaceutical residues in aquatic environments presents a significant ecological and public health challenge, necessitating innovative and sustainable remediation strategies. This study investigates the dual functionality of a synthesized nickel–aluminum layered double hydroxide (Ni–Al LDH) composite for the efficient removal of ciprofloxacin (CIP), a widely used antibiotic, from wastewater through both adsorption and photocatalytic degradation processes. The Ni–Al LDH was synthesized via co-precipitation and characterized using FE-SEM, EDX, XRD, FTIR, XPS, TGA, and BET techniques. Adsorption experiments demonstrated a maximum adsorption capacity of 14.03 mg g − 1 under optimized conditions, including an initial CIP concentration of 20 mg L − 1 , a contact time of 5 min, an adsorbent dosage of 0.125 g L − 1 , and a pH of 11. The photocatalytic degradation under solar irradiation achieved a removal efficiency of 78.7% at 60 min using 0.02 g of catalyst and an initial CIP concentration of 15 mg L − 1 . The kinetics and adsorption isotherm modeling confirmed the material’s high reactivity and affinity toward CIP. The novelty of this work lies in the application of dual-function Ni–Al LDH for the removal of a pharmaceutical pollutant, demonstrating rapid adsorption kinetics and an enhanced photocatalytic activity, a solar-driven, and a green approach involving ethanol and plant-based reagents for material regeneration, aligning with the sustainable water treatment goals. These findings highlight the material’s promise as an eco-friendly and efficient candidate for practical wastewater treatment applications.

A spontaneous Leidenfrost transitioning phenomenon

The boiling behavior of impacting droplets plays a critical role in spray cooling, directly governing the overall cooling efficiency. Among the various boiling regimes, transitional boiling is particularly significant, as it marks the onset of droplet instability. However, the dynamic interplay between transitional boiling and Leidenfrost rebound remains largely underexplored. In this Letter, we report a universal spontaneous Leidenfrost transitioning (SLT) phenomenon that reveals the coupled evolution of bubble-vapor dynamics, extending the current understanding. Using a custom-designed experimental setup featuring a transparent nano-film heater, we observe that droplets in the SLT regime initially experience vigorous contact boiling following the emergence of a distinctive fingering-crown structure. This stage is followed by repeated contact-levitation cycles, ultimately concluding in Leidenfrost rebound. To explain the formation of the fingering-crown structure, we propose a theoretical model in which a spatial vapor pressure gradient (Δpv) beneath the droplet, which is induced by a hyperbolic vertical vapor velocity distribution, acts as the key mechanism. This model is validated experimentally through combined hydrodynamic (ridge height and dynamic droplet radii) and thermodynamic (heat transfer evolution) analysis. Specifically, our results reveal a characteristic rise-fall pattern between the maximum Δpv and the initial surface temperature, spanning from nucleate boiling to stable Leidenfrost rebound. This trend shows a strong consistency with the predictions of the proposed theoretical model.

Optimizing operating conditions and stability evaluation of Fe/Co-NC catalyst in proton exchange membrane fuel cell

Incoherent phonon transport dominates the out-of-plane thermal conductivity of epitaxial van der Waals Bi2Se3/In2Se3 superlattices

The increase in thermal conductivity, κ, at small period lengths in covalently bonded semiconductor and oxide epitaxial superlattices (SLs) is a hallmark of coherent phonon transport and a route for improving heat dissipation in the thin limit. Here, we show that, on the contrary, the phonon coherence length remains shorter than the minimum SL period in van der Waals (vdW) SLs. We measured the cross-plane κz of epitaxial Bi2Se3/β-In2Se3 vdW SLs grown by molecular beam epitaxy; our results show that κ decreases monotonically with increasing interface density down to the two-layer period limit. This suggests that the weak interface vdW bonding of these SLs results in diffusive phonon transport over the whole period range. We discuss further reduction to single-layer SLs and its effects on crystal and interface quality. The results presented in this paper highlight a constraint for thermal management in vdW-based nanoelectronic and thermoelectric devices.

Surgery versus chemoradiotherapy in patients with stage T1bN0M0 esophageal cancer: a retrospective cohort study

Electric field-modulated AlGaN/GaN Schottky barrier diode with high breakdown voltage via polarized charge around thin GaN channel

In this work, electric field-modulated AlGaN/GaN Schottky barrier diodes (SBDs) with an AlN back barrier layer and a thin GaN channel layer are demonstrated. Benefiting from the built-in electric field (EB) induced via the positively polarized charge at the AlGaN/GaN interface and the negatively polarized charge at the GaN/AlN interface, the composite electric field in the GaN channel is effectively suppressed, when the diodes are reverse-biased. Compared to traditional GaN buffer SBDs, the breakdown voltage of AlGaN/GaN SBDs with AlN back barrier layer increases from −585 to −1122 V while the power figure-of-merit increases from 215 to 777 MW/cm2.

Dynamical spin susceptibility and magnetic ordering in a square-octagon lattice in the Hubbard model

Tough Supramolecular Glasses Enabled by Frustrated Non‐Covalent Complexation

Abstract Supramolecular glasses, as noncovalently cross‐linked amorphous materials, are hampered by a fundamental trade‐off between vitrification and mechanical performance. Here we propose a strategy—“frustrated non‐covalent complexation”—inspired by frustrated Lewis pairs to overcome this limitation. This is achieved by installing sterically hindering isopropyl groups adjacent to directional squaramide hydrogen‐bonding motifs. Relative to a nonfrustrated control, this design not only generates more loosely packed hydrogen‐bonded domains but also shifts the dominant interactions from squaramide–squaramide to squaramide–ester hydrogen bonding. The frustrated system yields a 4.3‐fold increase in mechanical toughness in the resulting supramolecular glass, facilitated by efficient energy dissipation through reversible hydrogen‐bond rupture. It also enhances interfacial adhesion, functioning as an effective impact‐resistant coating that mitigates substrate fracture. Overall, this work establishes frustrated noncovalent complexation as a powerful paradigm for designing high‐performance supramolecular glass materials.

Finding the Key: Binding of Metal‐Oxo Clusters to the Enzyme Active Site Enabled by “Click” (Bio)Conjugation

Abstract Molecular metal‐oxo nanoclusters with tunable redox and structural properties have emerged as powerful bio‐inorganic tools in catalysis, protein crystallization, and therapeutic applications. Despite their potential, interactions between discrete clusters and proteins are predominantly driven by nonspecific intermolecular interactions, which limit precise control over binding sites and functional outcomes. In this work, we introduce a new strategy to achieve site‐directed binding of vanadium‐based polyoxometalate clusters (POVs) to distinct regions of Hen Egg White Lysozyme (HEWL), an archetypal antimicrobial enzyme. Three novel hybrid POVs were designed and fully characterized, starting from an azide‐functionalized cluster ( Na‐V 6 ‐N 3 ), which was subsequently post‐functionalized with a hydrophobic hexyne group ( Na‐V 6 ‐Hex ) to probe nonpolar interactions, and α‐ d ‐mannopyranoside ( Na‐V 6 ‐Man ) to mimic the protein's natural substrate. Structural and spectroscopic analyses demonstrated that, in contrast to conventional nonhybrid POV clusters which bind nonspecifically to peripheral positively charged protein patches, the hybrid POVs achieve distinct binding behaviors. Specifically, Na‐V 6 ‐N 3 and Na‐V 6 ‐Man selectively target the glycosidic pocket, resembling the binding of the protein's natural substrate, while Na‐V 6 ‐Hex exhibits an unprecedented crystallization of two POV clusters in close proximity, which wrap around the protein surface. These findings highlight that strategic organic functionalization can circumvent electrostatic barriers to achieve site‐selective cluster–protein interactions, thus opening new avenues for the application of metal‐oxo clusters in biotechnology, drug delivery, and medicine.

Characterization of leakage errors in a transmon qubit due to resonant digital control

We present experimental measurements and analysis of leakage errors occurring during resonant digital control of a superconducting qubit. By increasing the amplitude of the digital pulse trains and therefore decreasing the duration of the control gates, from 100 to 40 ns for a π-gate, the leakage error rate measured per Clifford gate in a randomized benchmarking test increases from 4.3×10−4 to 2.4×10−3 and becomes the dominant source of single-qubit gate errors for our qubit; these error rates are 1–2 orders of magnitude larger than we measure when controlling the same qubit using traditional, shaped-analog signals. Simulations show the dominant leakage mechanism arises from the increased spectral power of the pulse trains at the frequency ω12 corresponding to excitations from the first excited state |1⟩ to the second excited state |2⟩. Our measurements demonstrate the fundamental limits to resonant digital control of low-anharmonicity qubits and outline the trade-off between reducing gate times while preserving gate fidelity. We discuss possible strategies for mitigating this issue in future digital control implementations.

Effects of meat-based, meat-based with α-tocopherol, and pesco-vegetarian diets on biomarkers associated with colorectal cancer risk: a randomized behavioral intervention trial

Semi-suspended graphene terahertz photothermoelectric detector

Terahertz (THz) waves, with their unique physical properties, have potential applications in a number of industries. However, current THz detectors are not widely used due to their poor sensitivity and response speed. Using semi-suspended graphene as the channel material, we present a THz photothermoelectric detector in this work. We show that the semi-suspended device has a better THz photothermoelectric response than non-suspended devices. Additionally, we calculate the temperature distribution of graphene in the channel and the resulting photoresponse voltage using heat conduction theory, validating the substrate impact on graphene heat conduction. This study offers an approach to build room-temperature THz detectors with high sensitivity and fast response.

Real-world modeling and simulation for the self-organized toroidal packing of a DNA chain

High-resolution self-referencing incoherent single-shot lensless imaging with direct image retrieval

Lensless imaging is a family of techniques that can produce images without the need for imaging optics. Conventional lensless imaging usually requires some combination of coherent illumination, a reference beam, an optical encoder, and an iterative image retrieval algorithm. Recent advances have expanded lensless imaging to incoherent illumination, although existing methods employ specialized optical encoders to achieve this. We present a single-shot, self-referencing incoherent lensless imaging technique, which is based only on mirrors, beam splitters, and a single detector. Notably, our technique does not require iterative image retrieval. This allows us to acquire real-time lensless video, as well as demonstrate very efficient noise suppression. We experimentally demonstrate the technique's quasi-infinite depth of focus, as well as the resolution, field of view, and dependence on the coherence of the illumination. The method opens up possibilities in low cost, high resolution, and easily accessible lensless imaging.