We investigate the oscillatory behaviour of the footpoints of twisted magnetic flux tubes in the solar photosphere. We identify the dominant magnetohydrodynamic (MHD) wave modes present in these waveguides and assess their role in energy transport. Using vector magnetograms from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager Space-weather HMI Active Region Patches (SDO/HMI SHARP) series of active region 11158, the footpoints of twisted flux tubes are identified as convex local maxima of the Integrated Average Current Deviation (IACD) field, which highlights regions of enhanced magnetic twist and current concentration. To study the waves propagating in these structures, we apply the Spectral Proper Orthogonal Decomposition (SPOD) method, which separates complex spatio-temporal data into oscillatory patterns and their characteristic frequencies. Our analysis shows that the footpoints of the twisted flux tubes support both kink and sausage MHD modes, with oscillations detected across multiple diagnostics, including IACD, the vertical magnetic field, and the vertical Poynting flux. The coexistence of these modes suggests nonlinear interactions or mode coupling within the twisted magnetic structures. These twisted flux tubes act as magnetic waveguides that modulate the vertical transport of energy between the photosphere and higher atmospheric layers. The inferred upward Poynting fluxes ( 10 5  -  10 6 W m - 2 ) indicate that such twisted magnetic features may contribute to localised chromospheric heating.
The Posterior Anchor-Anterior Rotation (PAAR) method is presented in this paper as a biomechanically and anatomically sound approach to correcting twisted nose abnormalities. By combining controlled posterior anchoring with focused anterior rotation, the PAAR method overcomes intrinsic cartilage memory and multi-vector deviation pressures, addressing the limitations of conventional septal repositioning techniques within the scope of the Septal Redirection Concept. This study involved 48 patients undergoing primary rhinoplasty who received repair of a twisted nose deformity via the PAAR procedure. This method achieves long-lasting alignment by preserving structural integrity through the use of a sufficient L-strut and targeted graft-mediated torque. A high correction rate was achieved. This biomechanically sound method of long-term septal realignment is based on the Septal Redirection Concept and employs a dual-mechanism strategy: posterior anchoring to create a stable structural base and anterior rotation to overcome intrinsic deforming pressures. The PAAR procedure is a significant addition to the current literature on structural and preservation-oriented rhinoplasty because it is both effective and innovative in addressing complex septal abnormalities.
Transient ground-state bleaching (GSB), stimulated emission (SE), and excited-state absorbance (ESA) are measured for betaine-30 (B30) in the first excited singlet state (S1) on picosecond time scales. In the viscous solvents glycerol, ethylene glycol, and deep eutectic solvents with intermediate viscosities, SE is seen to the red of the ground-state absorption band and ESA at shorter wavelengths. By contrast, SE is not seen in the nonviscous solvents acetone and ethyl acetate, although both GSB and ESA are prominent. Fluorescence is detectable at room temperature in ethylene glycol and glycerol and increases as the temperature is lowered but is not seen in acetone or ethyl acetate. The absence of SE and fluorescence in nonviscous solvents is consistent with previous suggestions that S1 can relax to a conformation in which radiative transitions to the ground state (S0) are forbidden. Viscous solvents evidently suppress this relaxation. Time-dependent DFT calculations for B30 in various solvents show that the relaxed configuration is strongly twisted. Molecular orbitals, excitation energies, and oscillator strengths are calculated for structures on minimum-energy paths for twisting using six different density functionals, including spin-opposite, range-separated double-hybrid functionals optimized for excited states. As the molecule twists, the oscillator strength for S0-S1 transitions decreases while ESA shifts to shorter wavelengths. Excitation from S0 to S1 has substantial π-π* character in the ground-state conformation but becomes almost entirely a charge-transfer transition as S1 relaxes, accounting for the loss of oscillator strength. The need for solvent rearrangement explains the sensitivity of the relaxation dynamics to viscosity and temperature.
In this work, we present a thorough analysis of the propagation of fiber modes carrying orbital angular momentum in twisted, tapered, ring-core optical fibers. By generalizing the usual coupled-mode approach to include the effect of twisting and tapering, we discuss how it is possible to achieve efficient power transfer between modes carrying different amounts of orbital angular momentum. Our model presents, to the best of our knowledge, the first unified coupled-mode framework incorporating tapering, twisting, and arbitrary perturbations. In addition, our results allow us to get a clear insight into the dynamics of vortex modes propagating through twisted ring core fibers.
While large π-conjugated nanoribbons possess highly tunable electronic properties, their potential in high-performance organic photovoltaics (OPVs) remains largely untapped. Herein, we report a π-extended nanoribbon-like electron acceptor, PDIY, featuring a molecular length of 4.85 nm (11 fused rings) and near-infrared absorption extending to 900 nm. PDIY is engineered with a perylene diimide core fused to dual rylene units and end-capped with Y-type acceptor moieties. The rigid conjugated framework effectively suppresses conformational/vibronic relaxation, weakens electron-phonon coupling, and yields an intrinsically low non-radiative voltage loss (ΔVnr) of 0.146 eV, among the lowest values reported to date, thereby enabling higher open-circuit voltage. Despite its large size, the twisted geometry of PDIY leads to a unique "low crystallinity, strong aggregation" behavior. This allows PDIY to serve as a potent morphology-directing additive that acts in a manner consistent with heterogeneous nucleation, inducing the formation of robust, large-diameter fibrillar networks within bulk-heterojunction blends. Consequently, the integration of PDIY yields a simultaneous enhancement across all photovoltaic parameters, boosting power conversion efficiencies (PCEs) from 19.62% to 20.57%. This work establishes twisted nanoribbon-like acceptor as a versatile molecular platform for the dual regulation of excited-state dynamics and active-layer morphology in next-generation OSCs.
We study samples and a dipolar model of magnetic rods arranged on twisted polygonal clusters in terms of the twist angle. We find that the relative twist between polygons induces noncollinear chiral phases, ranging from flux vortex closure to hedgehog like radial configurations. 
Chirality, quantified in terms of a bond order parameter, is an emergent property that behaves here as an Ising variable. The chiral configurations of the systems can be understood in terms of chirality and clock index order parameters, whose evolution with twist occurs through discontinuous switching of the magnetic textures. Within a fixed Ising chiral sector, the clock index, rooted in the $C_N$ invariance of the polygons, distinguishes chiral textures that share chirality. As the twist increases, it continuously shifts the preferred relative clock phase, but the N-fold anisotropy only allows discrete orientations; the competition produces a tilted N-fold energy landscape whose global minimum hops discontinuously between clock sectors. As the number of sites in the polygon grows, the resulting response displays a nonlinear crossover from rigid, Ising-like behavior to an almost $\rm U(1)$-invariant regime, governed by a twist-induced suppression of the emergent $Z_N$ clock anisotropy. Guided by symmetry considerations and the outcomes of the numerical minimization, we developed a Landau phenomenological description that is compatible with both the Ising-type chirality and the $Z_N$ clock anisotropy.
Retinal projection displays (RPDs) relying on Holographic Optical Elements (HOEs) suffer from limited eye-box, inferior efficiency, and pronounced chromatic dispersion. To tackle these challenges, we propose a multi-viewpoint RPD architecture that achieves eye-box expansion and efficiency enhancement through a twisted nematic liquid crystal (TN-LC) lens array. The extended Jones matrix-based broadband wide-FOV optimization algorithm (EJM-BWOA) is developed to optimize lens layer thickness and twist angle, thereby realizing superior broadband and wide-angle polarization performance. Results verify that the multi-viewpoint structure enhances display performance under maximum horizontal eye rotation of ±30°, with the fabricated HOE lens reaching an efficiency of 47.38%. Furthermore, the optimized TN-LC lens achieves a polarization conversion efficiency (PCE) exceeding 90% across the visible spectral range (380-780 nm), while remaining functional at incident angles from 0° to 50°. Moreover, the proposed lens exhibits superior focusing capability at the RGB central wavelengths (450 nm, 532 nm, 630 nm). Collectively, this study establishes a novel, to the best of our knowledge, design paradigm for compact, high-performance near-eye displays, paving the way for further advancements in next-generation wearable display technologies.
We show that electron crystals compete closely with non-Abelian fractional Chern insulators in the half-filled second moiré band of twisted bilayer MoTe2. Depending on the twist angle and microscopic model, these crystals can have non-zero or zero Chern numbers C. The C = 0 crystal occurs because contributions to the total Chern number from the full first band (+1) and half-full second band (-1) cancel. This is counterintuitive because the first two non-interacting bands in a given valley have the same Chern number  + 1. For these two reasons, we call this crystal an anti-topological crystal. The anti-topological crystal is a novel type of electron crystal that may occur in systems with multiple Chern bands at filling factors n > 1.
Dynamical control of quantum matter is a challenging, yet promising direction for probing strongly correlated states. Motivated by recent experiments in twisted MoTe_{2} that demonstrated optical control of magnetization, we propose a protocol for probing magnetization dynamics in flat-band ferromagnets. We investigate the nucleation and dynamical growth of magnetic bubbles prepared on top of a false vaccum in both itinerant ferromagnets and spin-polarized Chern insulators. For ferromagnetic metals, we emphasize the crucial role of a nontrivial quantum geometry in the magnetization dynamics, which in turn also provides a probe for the quantum metric. Furthermore, for quantum Hall ferromagnets, we show how properties of chiral edge modes localized at domain-wall boundaries can be dynamically accessed. Our Letter demonstrates the potential for nonequilibrium protocols to control and probe strongly correlated phases, with particular relevance for twisted MoTe_{2} and graphene-based flat-band ferromagnets.
A 7-year-old neutered male domestic shorthair cat was presented for evaluation of a large intra-abdominal mass. Contrast-enhanced CT revealed a pedunculated hepatic mass measuring 15 × 9.5 × 6.5 cm arising from the papillary process of the caudate lobe, without evidence of metastasis. A three-port laparoscopic liver lobectomy was performed. The mass, attached by a torsed pedicle, was excised using a bipolar advanced energy vessel sealing device (ENSEAL; Ethicon). Histopathology confirmed a primary hepatic fibrosarcoma with complete resection. The cat recovered uneventfully, was discharged the following day and received five cycles of adjuvant doxorubicin (Adriamycin; Pfizer), maintaining an excellent quality of life and stable disease for at least 3 years. This is the first report of laparoscopic liver lobectomy in a cat with a large torsed hepatic mass. The case demonstrates that minimally invasive liver lobectomy can be successfully performed in feline patients, even in challenging cases involving substantial or torsed lobes. Removing a part of a cat liver using a minimally invasive surgery A 7-year-old male cat was found to have a large growth on his liver. Scans showed that the growth was attached by a twisted stalk, but there was no sign that it had spread elsewhere. The cat underwent a minimally invasive surgery, called a laparoscopic liver lobectomy, to remove the affected part of the liver. The growth was successfully removed, and laboratory testing confirmed it was a type of liver tumour called fibrosarcoma. The cat recovered very well from surgery and went home the next day. He also received additional chemotherapy to reduce the chance of the tumour coming back. Three years after the surgery, the cat remained healthy, happy and showed no signs of disease. This case is important because it is the first report of minimally invasive liver surgery being used in a cat with a large, twisted liver tumour. It shows that even complex liver problems in cats can be treated safely with less invasive techniques, which can help cats recover faster and maintain a good quality of life.
Elucidating excited-state conformational dynamics in D-π-A systems is central to the development of functional molecules. In particular, the emergence of twisted intramolecular charge transfer (TICT) states offers a powerful handle to regulate electronic relaxation pathways through molecular design. Herein, a systematic investigation of two structurally similar D-π-A chromophores (SV27 and SV31) is engineered to either suppress or facilitate excited-state twisting. The control molecule SV27 exhibits limited conformational flexibility and relaxes predominantly through a locally excited state, whereas the strategic incorporation of a sterically demanding donor fragment in SV31 induces substantial excited state torsional reorganization, leading to the stabilization of a TICT state. A combination of steady-state spectroscopy, time-resolved fluorescence measurements, and quantum chemical calculations reveals a strong coupling between molecular architecture, excited-state potential energy surfaces, and charge transfer dynamics. Solvent-dependent studies further demonstrate that higher polarity of the medium selectively stabilizes the twisted charge separated state, which is identified as a crucial element for the accessibility of TICT. Upon leveraging this sensitivity to the local environment, the TICT-active chromophore SV31 is employed as a highly responsive fluorescent probe for trace water detection in organic solvents, achieving trace level sensitivity (30 ppm). Altogether, this study offers a rational framework by correlating molecular architecture with excited-state twisting and charge separation, providing a rationale for activating TICT and laying the foundation for the development of advanced functional molecular architectures for the detection of water.
Isolated fallopian tube torsion (IFTT) is a rare condition in which the fallopian tube undergoes torsion without ovary involvement. The causes of IFTT vary widely, ranging from intrinsic abnormalities of the fallopian tube itself to extrinsic factors affecting the peritubal environment. Here, we report a case of IFTT concomitant with an adenomatoid tumor arising from the fallopian tube. A 49-year-old triparous patient presented with sudden-onset lower abdominal pain. Imaging findings revealed a 3-cm solid mass in the subserosal area of the left fallopian tube, and laparoscopy confirmed IFTT involving a dark red and solid mass. Histologically, an adenomatoid tumor was identified in the twisted fallopian tube. Adenomatoid tumors of the fallopian tube are typically small, asymptomatic, and identified incidentally during gynecologic surgeries or imaging; therefore, this tumor is an extremely rare cause of IFTT. Adenomatoid tumors in the fallopian tube, even those as small as 3 cm, can result in torsion.
Reflectance spectra of Chrysinacupreomarginata's elytra are measured for visible wavelengths. The spectra consist of both left- and right-handed circularly polarized light, which suggests the presence of two chitin-based helicoidal structures separated by a unidirectional layer, as reported for the Chrysina resplendens scarabs. This fact has been corroborated by the analysis of scanning electron microscopy imaging. The structural and effective pitches of each helicoid have been obtained from these images. The height and width of the reflectance bands are linked with the presence of uric acid crystallites through the arrangement of oriented chitin fibrils embedded in the proteinaceous matrix. Calculated left- and right-handed circularly polarized reflectance spectra are evaluated from a radiative transfer matrix formalism. The photonic characterization of each helicoid is carried out in terms of the variation of the optical gap with depth through the twisted arrangements. A novel, to our knowledge, approach is developed to obtain the depth-dependence of both the uric acid volume fractions through each helical structure and the spectral positions and widths of the photonic band gaps. When modeling reflectance spectra to resemble measured ones, it is necessary to significantly increase the volume fraction of uric acid in the unidirectional layer for it to function as a half-wave plate.
In this study, a series of bipolar acceptor materials, DPQCN-oPhCz, DPQCN-pPhCz, and DPQCN-pPhCzt, featuring a cyano-substituted diphenylquinoxaline (DPQCN) core conjugated with various phenylcarbazole derivatives, were successfully synthesized and characterized. The molecular design introduces a strongly electron-withdrawing cyano substituent into the diphenylquinoxaline framework to lower the LUMO energy level and improve the bipolar charge-transport properties. Photophysical investigations and theoretical calculations revealed distinct intramolecular charge transfer characteristics, resulting from the effective spatial separation of the frontier molecular orbitals. Specifically, the introduction of tert-butyl groups and a twisted conformation in DPQCN-pPhCzt not only increased the steric bulk to suppress molecular aggregation but also facilitated the formation of an efficient exciplex when blended with the donor material TCTA. Thermodynamic analysis using the Rehm-Weller equation further confirmed the strong driving force for exciplex formation in these D-A systems. These results, characterized by high thermal stability, well-aligned energy levels, and minimal singlet-triplet energy gaps (ΔEST), underscore the significant potential of this DPQCN-based series as high-performance exciplex hosts for achieving OLEDs with high brightness and low turn-on voltages.
Opening a bandgap in bilayer graphene typically requires either structural modification or continuous external electric fields, while twisted bilayer graphene configurations remain largely gapless without additional perturbation. Here, we demonstrate bandgap opening of up to 50 meV in structurally intact bilayer graphene by in-plane strain fields imposed by an interfaced porous organic 2D crystal. These sandwich graphene/organic 2D crystal/graphene (G-O2DC-G) heterostructures, with O2DCs of honeycomb lattice structure and with pore sizes ranging from 9.6 to 31.0 Å, template corrugation that brings graphene layers into localized Bernal-stacked contact within the pores. We identify a critical pore size threshold of ∼18 Å, above which the graphene layers establish direct contact with interlayer spacing of ∼3.34 Å as in Bernal-stacked bilayer. The bandgap exhibits a non-monotonic dependence on pore size, reaching its maximum at ∼19 Å (G-TTI-G) before declining with further pore expansion. We propose this strain-based approach as a design principle for bandgap engineering in graphene, leveraging the chemical diversity of O2DCs for potential applications in graphene-based semiconductor devices.
Non-planar aromatic hydrocarbons display distorted π-frameworks that give rise to unique optoelectronic properties. Among the different strategies for generating non-planar aromatic hydrocarbons, steric overcrowding has afforded numerous twisted structures displaying helical or alternate twists, whereas bent structures remain rare. Herein, we report a pyrene-fused azaacene derivative in which eight strategically positioned phenyl substituents enforce bending of the aromatic core rather than twisting, generating a negatively curved, saddle-shaped structure. Single-crystal x-ray diffraction reveals large deviations from planarity with bend angles of 41° and 34°, stabilised by intramolecular π-π stacking between facing phenyl rings.
We report a combined experimental and theoretical study of the formation and decay dynamics of a ground-state twisted intermediate (TI) involved in the ultrafast internal conversion of UV-excited pyrimidine nucleosides and nucleotides in aqueous solution. Infrared transient absorption spectroscopy identifies a TI featuring a strongly twisted C5=C6 double bond, and its quantum yield (ΦTI) and lifetime (τTI) are determined for structurally distinct nucleosides and nucleotides. Photohydration rates (khyd) measured under continuous 266 nm irradiation correlate directly with ΦTI × τTI, providing unambiguous evidence that the TI mediates the hydration reaction. Comparison of C5-H and C5-CH3 derivatives reveals pronounced reductions in both ΦTI and khyd upon methylation. Quantum mechanics/molecular mechanics dynamical simulations show that TI formation requires sufficient nuclear momentum along the TI-forming coordinate at the conical intersection, whereas vibrational energy randomization induced by C5 methylation and solvent interactions diminishes this momentum and consequently ΦTI. The TI is neither diradical nor zwitterionic but instead contains an elongated, highly reactive C5=C6 double bond whose polarization and hydration reactivity are attenuated by C5 methylation. Consistently, the normalized reactivity index, khyd/(ΦTI × τTI), is substantially lower for C5-methylated compounds. A high activation barrier limits the photohydration quantum yield (∼0.01), and τTI is primarily governed by isomerization back to the planar ground-state structure.
Mitochondrial viscosity is a key microenvironmental parameter regulating its function, and its dysregulation is associated with various diseases. However, achieving specific and dynamic monitoring of mitochondrial viscosity remains challenging. To address this, we developed a novel near-infrared fluorescent probe, FTZ-BTZ, based on a twisted intramolecular charge transfer mechanism. The probe demonstrates high sensitivity (R2 = 0.9906), excellent selectivity, good stability, and low cytotoxicity in viscosity detection. Colocalization imaging confirmed its precise mitochondrial targeting capability, with a Pearson's coefficient of 0.9052. Using this probe, we successfully achieved real-time, in situ visualization of dynamic changes in mitochondrial viscosity within living cells. These changes were induced by various pharmacological stimuli, including lipopolysaccharide, dexamethasone, nystatin, and monensin. Specifically, we established the concentration-dependent response of mitochondrial viscosity to monensin. Further in vivo experiments showed that FTZ-BTZ can effectively distinguish viscosity gradients induced by different drug stimulations in mouse models. The FTZ-BTZ probe developed in this work provides a high-performance molecular tool for real-time investigation of mitochondrial viscosity-related physiological and pathological processes at the subcellular level.
Lipid droplet accumulation is a pathological hallmark of nonalcoholic fatty liver disease (NAFLD); however, the utility of current lipid droplet-targeted fluorescent probes for in vivo diagnosis is hindered by shallow tissue penetration and strong background autofluorescence. To overcome these challenges, here, we report three donor-acceptor-acceptor solvatochromic probes (CTBT-ANPy, PTBT-ANPy, and MOPTBT-ANPy) with tunable electron-donating groups, enabling near-infrared (NIR) imaging of lipid droplets and in vivo NAFLD diagnosis. Owing to multiple intramolecular interactions and restriction of twisted intramolecular charge transfer, these probes exhibit intense NIR emissions (up to 709 nm, quantum yield of 34.2%) in low-polarity media. These lipophilic probes display high lipid-droplet specificity with bright light-up signals and wash-free capacity. With the aid of NIR-emissive MOPTBT-ANPy, in vivo high-contrast fluorescent discrimination of NAFLD in a mouse model was successfully achieved. This study underscores the potential of high-performance NIR probes for noninvasive accurate NAFLD diagnosis and monitoring.
Fluorination of building block molecules is one of the effective engineering approaches to modulate molecular assembly in crystalline organic materials. Herein, we constructed a hydrogen-bonded organic framework (HOF) from a tetraphenylethene derivative, F-CBPE, possessing 3,5-difluoro-4-carboxyphenyl groups. The introduction of fluorine atoms in ortho-positions of the carboxy group makes the conformation of the arms more twisted, resulting in a framework structure different from that formed with the pristine molecule. The resulting HOF, F-CBPE-1(MeBz), is composed of sql-topological hydrogen-bonded network sheets accumulating in a staggered manner without interpenetration; while, the HOF of the pristine compound (CBPE) is composed of three-directionally interpenetrated sql-network sheets. Fluorescence spectroscopy and single-crystal microscopy revealed key features of the photophysical behavior of these HOFs. The solvated F-CBPE HOF exhibits blue emission due to an intramolecular charge transfer (ICT) event occurring in <15 ps, whereas desolvation induces a red shift, which is attributed to excimer-like species formed in 120 ps and arising from changes in the stacking arrangement of the layers. These findings show the effect of fluorination on the structures and fluorescence behavior of tetraphenylethene-based HOFs, which were thoroughly compared to the pristine CBPE molecule and related derivatives.