Evaluation of anorectal function using real-time tissue elastography before and after preoperative chemoradiotherapy.

PURPOSE: This study aimed to clarify the relationship between changes in elasticity and anorectal function before and after chemoradiotherapy. METHODS: This is a single-center prospective cohort study (Department of Surgical Oncology, The University of Tokyo). We established a technique to quantify internal anal sphincter hardness as elasticity using transanal ultrasonography with real-time tissue elastography. Twenty-seven patients with post-chemoradiotherapy rectal cancer during 2019-2022 were included. Real-time tissue elastography with transanal ultrasonography was performed before and after chemoradiotherapy to measure internal anal sphincter hardness as "elasticity" (hardest (0) to softest (255); decreased elasticity indicated sclerotic changes). The relationship between the increase or decrease in elasticity pre- and post-chemoradiotherapy and the maximum resting pressure, maximum squeeze pressure, and Wexner score were the outcome measures. RESULTS: A decrease in elasticity was observed in 16/27 (59.3%) patients after chemoradiotherapy. Patients with and without elasticity decrease after chemoradiotherapy comprised the internal anal sphincter sclerosis and non-sclerosis groups, respectively. The maximum resting pressure post-chemoradiotherapy was significantly high in the internal anal sphincter sclerosis group (63.0 mmHg vs. 47.0 mmHg), and a majority had a worsening Wexner score (60.0% vs. 18.2%) compared with that of the non-sclerosis group. Decreasing elasticity (internal anal sphincter sclerosis) correlated with a higher maximum resting pressure (r = 0.36); no correlation was observed between the degree of elasticity change and maximum squeeze pressure. CONCLUSION: Internal anal sphincter sclerosis due to chemoradiotherapy may correlate to anorectal dysfunction.

Development of an Iron(II) Complex Exhibiting Thermal- and Photoinduced Double Proton-Transfer-Coupled Spin Transition in a Short Hydrogen Bond.

Multiple proton transfer (PT) controllable by external stimuli plays a crucial role in fundamental chemistry, biological activity, and material science. However, in crystalline systems, controlling multiple PT, which results in a distinct protonation state, remains challenging. In this study, we developed a novel tridentate ligand and iron(II) complex with a short hydrogen bond (HB) that exhibits a PT-coupled spin transition (PCST). Single-crystal X-ray and neutron diffraction measurements revealed that the positions of the two protons in the complex can be controlled by temperature and photoirradiation based on the thermal- and photoinduced PCST. The obtained results suggest that designing molecules that form short HBs is a promising approach for developing multiple PT systems in crystals.

Molecular Structures and Vibrational Spectra of trans- and cis-Polyacetylene and Their Oligoenes Revisited Using Density Functional Theory Calculations.

Polyacetylene, the most representative synthetic conducting polymer, has attracted much attention because it exhibits high conductivity upon doping. In this paper, molecular structures, electronic excitation energies, and Raman and infrared spectra were calculated using density functional theory for trans- and cis-oligoenes with various chain lengths up to the number of C═C bonds (n) of 100 and trans- and cis-polyacetylenes under one-dimensional periodic boundary condition. The harmonic vibrational frequencies obtained at the B3LYP/6-311G(d,p) level were scaled by the scaling factors determined with respect to the anharmonic vibrational frequencies using the B2PLYP method, in which the coefficients of the functional were optimized for trans-oligoenes. The calculated infrared and Raman frequencies reproduce reasonably well the observed frequencies for trans- and cis-polyacetylene. Based on the chain-length dependence of the calculated Raman spectra of trans-oligoenes, we proposed the possibility of longer conjugated trans-segments observed in the resonance Raman spectra of trans-polyacetylene excited at longer wavelengths of 647.1 and 1064 nm. We also elucidated the origin of the excitation-wavelength dependence of the resonance Raman spectra of trans-polyacetylene and the structure of isomerization intermediates from cis-form to trans-form. In addition, the previous assignments of Raman and infrared spectra of trans- and cis-polyacetylene were reexamined in the present study based on the chain-length dependence of the spectra.

Temporal changes in functional outcomes of stapled and hand-sewn ileal pouch-anal anastomosis for ulcerative colitis and familial adenomatous polyposis.

AIM: Little is known about how ileal pouch-anal anastomosis (IPAA) influences anorectal manometric data. This study aimed to clarify temporal changes in anorectal manometric data and faecal incontinence in IPAA. METHODS: We examined 32 patients with ulcerative colitis (UC) or familial adenomatous polyposis (FAP) undergoing restorative proctocolectomy with stapled or hand-sewn IPAA. Maximum resting pressure (MRP) and maximum squeezing pressure (MSP) were analysed before and 1-3, 6-9, and 12-24 months after IPAA. Cleveland Clinic Florida-Faecal Incontinence Score (CCF-FIS) was measured 6-9 and 12-24 months after IPAA. RESULTS: Fourteen patients underwent stapled IPAA and 18 patients underwent hand-sewn IPAA. MRP decreased 1-3 months after stapled IPAA (median: 42.3 mmHg vs. 60.0 mmHg at preoperative value, p = 0.039), but recovered afterwards. In hand-sewn IPAA, the median MRP decreased to 29.5 mmHg at 1-3 months after IPAA (baseline: 64.8 mmHg, p < 0.0001), and remained unchanged thereafter. Stapled IPAA did not affect MSP; however, hand-sewn IPAA caused a reduction in the median MSP from 191.3 mmHg to 141.3 mmHg at 1-3 months (p = 0.035), which gradually increased afterwards. The median CCFFIS was 5.5 points at 6-9 months and 2 points at 12-24 months after stapled IPAA. The score was high (11 points) at 6-9 months but decreased to 5 points at 12-24 months after hand-sewn IPAA (p = 0.022). CONCLUSION: We present time trends in functional outcomes of IPAA. MRP showed a transient decrease after stapled IPAA, whereas it remained low after hand-sewn IPAA. CCFFIS was high only at 6-9 months after hand-sewn IPAA.

Controlling Diradical Character of Photogenerated Colored Isomers of Phenoxyl-Imidazolyl Radical Complexes.

We propose a rational method for evaluating the diradical character of the photochromic phenoxyl-imidazolyl radical complex (PIC) derivatives based on their radical-radical coupling reaction rates. PIC consists of an imidazole ring, a phenoxyl ring, and a bridging unit that structurally connects them. The C-N bond formed between the imidazole and phenoxyl rings can be dissociated photochemically in a homolytic manner. The photochromism of PIC differs significantly from other photochromic molecules in that the transient colored open-ring isomer has a diradical character. The colored open-ring isomer returns promptly to the initial colorless closed-ring isomer by the intramolecular radical recombination reaction. By changing the aromaticity and substitution position of the bridging unit, it is possible to control the degree of contribution of the open-shell diradical and closed-shell quinoidal structures to the open-ring isomer. Systematic investigation of the photochromic reactions of several PIC derivatives revealed that the half-life of the open-ring isomers reflects the diradical character. Thus, the radical recombination reaction rate of the open-ring isomer of the PIC derivatives is an excellent parameter of the diradical character.

Excited-state dynamics of dipyrrolyldiketone difluoroboron complexes.

Anion-responsive photofunctional materials have been extensively studied because anions are important for biotic activity and constitute the building blocks of elegant supramolecular architectures. A number of fluorescent anion receptors that can probe anions in their environments have been reported, but the excited states of many of these molecules remain elusive. Studies on excited-state dynamics provide fruitful information for optimizing the emission properties, minimizing the photodegradation and photorelease of anions, and exploring novel photofunctions. In this study, we investigated the excited-state dynamics of an aryl-substituted dipyrrolyldiketone difluoroboron complex, a π-conjugated anion receptor, by time-resolved visible and infrared absorption spectroscopy and emission decay measurements combined with quantum chemical calculations. Anion binding was found to alter the radiative and nonradiative rate constants and the excited-state absorption of the anion receptor. In contrast, the molecular structures and binding abilities were similar in the S0 and S1 states.

Impact of Door-to-Balloon Time Reduction Depending on the Killip Classification in Patients with ST-Segment Elevation Myocardial Infarction Transported by Emergency Medical Services.

The coronavirus disease 2019 pandemic occurred in several countries, making the conventional medical system difficult to maintain. Recent recommendations aim to prevent nosocomial infections and infections among health care workers. Therefore, establishing a cardiovascular medical system under an emergency for patients with ST-segment elevation myocardial infarction (STEMI) is desired. This study aimed to determine the relationship between prognosis and door-to-balloon time (DBT) shortening based on the severity on arrival.This retrospective, multi-center, observational study included 1,127 consecutive patients with STEMI. These patients were transported by emergency medical services and underwent primary percutaneous coronary intervention. Patients were stratified according to the Killip classification: Killip 1 (n = 738) and Killip ≥ 2 (n = 389) groups.Patients in the Killip ≥ 2 group were older, with more females, and more severity on arrival than those in the Killip 1 group. The 30-day mortality rate in the Killip 1 and Killip ≥ 2 groups was 2.2% and 18.0%, respectively. The Killip ≥ 2 group had a significant difference in the 30-day mortality between patients with DBT ≤ 90 minutes and those with DBT > 90 minutes; however, this did not occur in the Killip 1 group. Furthermore, multivariate analysis revealed that DBT ≤ 90 minutes was not a significant predictive factor in the Killip 1 group; however, it was an independent predictive factor in the Killip ≥ 2 group.DBT shortening affected the 30-day mortality in STEMI patients with Killip ≥ 2, although not those with Killip 1.

Photoinduced Persistent Polarization Change in a Spin Transition Crystal.

Using light as a local heat source to induce a temporary pyroelectric current is widely recognized as an effective way to control the polarization of crystalline materials. In contrast, harnessing light directly to modulate the polarization of a crystal via excitation of the electronic bands remains less explored. In this study, we report an FeII spin crossover crystal that exhibits photoinduced macroscopic polarization change upon excitation by green light. When the excited crystal relaxes to the ground state, the corresponding pyroelectric current can be detected. An analysis of the structures, magnetic properties and the Mössbauer and infrared spectra of the complex, supported by calculations, revealed that the polarization change is dictated by the directional relative movement of ions during the spin transition process. The spin transition and polarization change occur simultaneously in response to light stimulus, which demonstrates the enormous potential of polar spin crossover systems in the field of optoelectronic materials.

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation.

Photochromic materials have been widely used in various research fields because of their variety of photoswitching properties based on various molecular frameworks and bond breaking processes, such as homolysis and heterolysis. However, while a number of photochromic molecular frameworks have been reported so far, there are few reports on photochromic molecular frameworks that show both homolysis and heterolysis depending on the substituents with high durability. The biradicals and zwitterions generated by homolysis and heterolysis have different physical and chemical properties and different potential applications. Therefore, the rational photochromic molecular design to control the bond dissociation in the excited state on demand expands the versatility for photoswitch materials beyond the conventional photochromic molecular frameworks. In this study, we synthesized novel photochromic molecules based on the framework of a radical-dissociation-type photochromic molecule: phenoxyl-imidazolyl radical complex (PIC). While the conventional PIC shows the photoinduced homolysis, the substitution of a strong electron-donating moiety to the phenoxyl moiety enables the bond dissociation process to be switched from homolysis to heterolysis. This study gives a strategy for controlling the bond dissociation process of the excited state of photochromic systems, and the strategy enables us to develop further novel radical and zwitterionic photoswitches.

Geometrical Evolution and Formation of the Photoproduct in the Cycloreversion Reaction of a Diarylethene Derivative Probed by Vibrational Spectroscopy.

The front cover artwork is provided by the groups of Prof. Hiroshi Miyasaka (Osaka University, Japan), Prof. Masahiro Irie (Rikkyo University, Japan), Prof. Seiya Kobatake (Osaka City University, Japan) and Prof. Akira Sakamoto (Aoyama Gakuin University, Japan). The image shows the coherently vibrating closed form of a photochromic diarylethene derivative in the excited state, and subsequent structural evolution into the open form in the cycloreversion reaction. Read the full text of the Article at 10.1002/cphc.202000315.

Geometrical Evolution and Formation of the Photoproduct in the Cycloreversion Reaction of a Diarylethene Derivative Probed by Vibrational Spectroscopy.

The geometrical evolution of the reactant and formation of the photoproduct in the cycloreversion reaction of a diarylethene derivative were probed using time-resolved absorption spectroscopies in the visible to near-infrared and mid-infrared regions. The time-domain vibrational data in the visible region show that the initially formed Franck-Condon state is geometrically relaxed into the minimum in the excited state potential energy surface, concomitantly with the low-frequency coherent vibrations. Theoretical calculations indicate that the nuclear displacement in this coherent vibration is nearly parallel to that in the geometrical relaxation. Time-resolved mid-infrared spectroscopy directly detected the formation of the open-ring isomer with the same time constant as the decrease of the closed-ring isomer in the excited state minimum. This observation reveals that no detectable intermediate, in which the population is accumulated, is present between the excited closed-ring isomer and the open-ring isomer in the ground state.

Femtosecond Polarization Switching in the Crystal of a [CrCo] Dinuclear Complex.

Capability to control macroscopic molecular properties with external stimuli offers the possibility to exploit molecules as switching devices of various types. However, application of such molecular-level switching has often been limited by its speed and thus efficiency. Herein, we demonstrate ultrafast, photoinduced polarization switching in the crystal of a [CrCo] dinuclear complex by ultrafast pump-probe spectroscopy in the visible and mid-infrared regions. The photoinduced polarization switching was found to have a time constant of 280 fs, which makes the [CrCo] complex crystal the fastest polarization-switching material realized using the metastable state. Moreover, the pump-probe data in the visible region reveal the pronounced appearance of coherent nuclear wavepacket motion with a frequency as low as 22 cm-1 , which we attribute to a lattice vibrational mode. The pronounced non-Condon effect for its resonance Raman enhancement implies that this mode couples the relevant electronic states, thereby facilitating the ultrafast polarization switching.

Three-Step Spin State Transition and Hysteretic Proton Transfer in the Crystal of an Iron(II) Hydrazone Complex.

A proton-electron coupling system, exhibiting unique bistability or multistability of the protonated state, is an attractive target for developing new switchable materials based on proton dynamics. Herein, we present an iron(II) hydrazone crystalline compound, which displays the stepwise transition and bistability of proton transfer at the crystal level. These phenomena are realized through the coupling with spin transition. Although the multi-step transition with hysteresis has been observed in various systems, the corresponding behavior of proton transfer has not been reported in crystalline systems; thus, the described iron(II) complex is the first example. Furthermore, because proton transfer occurs only in one of the two ligands and π electrons redistribute in it, the dipole moment of the iron(II) complexes changes with the proton transfer, wherein the total dipole moment in the crystal was canceled out owing to the antiferroelectric-like arrangement.

Synthesis of Belt- and Möbius-Shaped Cycloparaphenylenes by Rhodium-Catalyzed Alkyne Cyclotrimerization.

A belt-shaped [8]cycloparaphenylene (CPP) and an enantioenriched Möbius-shaped [10]CPP have been synthesized by high-yielding rhodium-catalyzed intramolecular cyclotrimerizations of a cyclic dodecayne and a pentadecayne, respectively. This Möbius-shaped [10]CPP possesses stable chirality and isolated with high enantiomeric purity. It is evident from the reaction Gibbs energy calculation that the above irreversible cyclotrimerizations are highly exothermic; therefore establishing that the intramolecular alkyne cyclotrimerization is a powerful route to strained cyclic molecular strips.

Observation of Proton Transfer Coupled Spin Transition and Trapping of Photoinduced Metastable Proton Transfer State in an Fe(II) Complex.

An important technique to realize novel electron- and/or proton-based functionalities is to use a proton-electron coupling mechanism. When either a proton or electron is excited, the other one is modulated, producing synergistic functions. However, although compounds with proton-coupled electron transfer have been synthesized, crystalline molecular compounds that exhibit proton-transfer-coupled spin-transition (PCST) behavior have not been reported. Here, we report the first example of a PCST Fe(II) complex, wherein the proton lies on the N of hydrazone and pyridine moieties in the ligand at high-spin and low-spin Fe(II), respectively. When the Fe(II) complex is irradiated with light, intramolecular proton transfer occurs from pyridine to hydrazone in conjunction with the photoinduced spin transition via the PCST mechanism. Because the light-induced excited high-spin state is trapped at low temperatures in the Fe(II) complex-a phenomenon known as the light-induced excited-spin-state trapping effect-the light-induced proton-transfer state, wherein the proton lies on the N of hydrazone, is also trapped as a metastable state. The proton transfer was accomplished within 50 ps at 190 K. The bistable nature of the proton position, where the position can be switched by light irradiation, is useful for modulating proton-based functionalities in molecular devices.

Selective resonance Raman enhancement of large amplitude inter-ring vibrations of [34](1,2,4,5)cyclophane radical cation; a model of π-stacked dimer radical ions.

The compound [34](1,2,4,5)cyclophane, which consists of π-stacked two benzene rings, is one of the simplest dimeric molecules with a transannular π-π interaction. Its radical cation showed a characteristic near-infrared electronic absorption due to a transition from "bonding" to "anti-bonding" orbitals between the two benzene moieties. The Raman spectrum was measured in resonance with this electronic transition, and selective enhancement of low-frequency vibrational bands was observed. The strongest band at 241 cm-1 was assigned to one of the inter-ring vibrations that changed the distance between the two benzene rings. The Raman cross-section of this band was estimated to be 9.1 × 10-25 cm-2, which was comparable to typical resonance Raman cross-sections and 100 times stronger than those of the local ring-breathing vibrations (1230 and 1262 cm-1) of the radical cation. To understand this resonance Raman enhancement, the polarized Raman spectra were measured. The depolarization ratios of the cation bands were almost 1/3, which indicates an A-term rigorous resonance Raman effect with a contribution of a single electronic excited state. To analyze this A-term resonance Raman effect, the optimized geometry was calculated for the electronic excited S2 state of the radical cation responsible for its near-infrared electronic absorption. The bond lengths of the excited S2 state were almost the same as those of the ground state, while the distance between the two benzene rings extended by 7%. Large Franck-Condon factors were, thus, expected for the inter-ring vibrations, and resulted in the selective resonance Raman enhancement of these large amplitude vibrations.

Direct Observation of the Ultrafast Evolution of Open-Shell Biradical in Photochromic Radical Dimer.

Delocalized biradicals have been extensively studied because of fundamental interests to singlet biradicals and several potential applications such as to two-photon absorption materials. However, many of the biradical studies only focus on the static properties of the rigid molecular structures. It is expected that the biradical properties of the delocalized biradicals are sensitive to the subtle changes of the molecular structures and their local environments. Therefore, the studies of the dynamic properties of the system will give further insight into stable radical chemistry. In this study, we directly probe the ultrafast dynamics of the delocalized biradical of a photochromic radical dimer, pentaarylbiimidazole (PABI), by time-resolved visible and infrared spectroscopies and quantum chemical calculations with the extended multistate complete active space second-order perturbation theory (XMS-CASPT2). While the photogenerated transient species was considered to be a single species of the biradical, the present ultrafast spectroscopic study revealed the existence of two transient isomers differing in the contributions of biradical character. The origin of the two metastable isomers is most probably due to the substantial van der Waals interaction between the phenyl rings substituted at the imidazole rings. Unraveling the temporal evolution of the biradical contribution will stimulate to explore novel delocalized biradicals and to develop biradical-based photofunctional materials utilizing the dynamic properties.

Directional Electron Transfer in Crystals of [CrCo] Dinuclear Complexes Achieved by Chirality-Assisted Preparative Method.

The polarization switching mechanism is used in various devices such as pyroelectric sensors and memory devices. The change in polarization mostly occurs by ion displacement. The development of materials whose polarization switches via electron transfer in order to enhance operation speed is a challenge. We devised a synthetic and crystal engineering strategy that enables the selective synthesis of a [CrCo] heterometallic dinuclear complex with a polar crystal structure, wherein polarization changes stem from intramolecular charge transfer between Co and the ligand. Polarization can be modulated both by visible-light irradiation and temperature change. The introduction of chiral ligands was paramount to the successful polarization switching in the valence tautomeric compound. Mixing Cr and Co complexes with enantiopure chiral ligands resulted in the selective formation of only pseudosymmetric [CrCo] heterometallic complexes. Furthermore, the left-handed chiral ligands preferentially interacted with their right-handed counterparts, enabling molecules to form a polar crystal structure.

Stepwise Two-Photon-Gated Photochemical Reaction in Photochromic [2.2]Paracyclophane-Bridged Bis(imidazole dimer).

Stepwise two-photon processes not only have great potential for efficient light harvesting but also can provide valuable insights into novel photochemical sciences. Here we have designed a [2.2]paracyclophane-bridged bis(imidazole dimer), a molecule that is composed of two photochromic units and absorbs two photons in a stepwise manner. The absorption of the first photon leads to the formation of a short-lived biradical species (half-life = 88 ms at 298 K), while the absorption of the additional photon by the biradical species triggers a subsequent photochromic reaction to afford a long-lived quinoid species. The short-lived biradical species and the long-lived quinoid species display significantly different absorption spectra and rates of the thermal back-reaction. The stepwise two-photon excitation process in this photochromic system can be initiated even by incoherent continuous-wave light irradiation, indicating that this two-photon reaction is highly efficient. Our molecule based on the bridged bis(imidazole dimer) unit should be a good candidate for multiphoton-gated optical materials.

Clinical Outcome After Permanent Pacemaker Implantation in Patients With a High Percentage of Ventricular Pacing.

Previous reports have suggested that right ventricular apical pacing may lead to cardiac dysfunction. Septal pacing is thought to be superior to apical pacing in the prevention of cardiac dyssynchrony, however, there have been no reports on the contribution of septal pacing to improving clinical outcome.We retrospectively evaluated factors associated with cardiac events in patients with right ventricular pacing.The study population consisted of 256 consecutive patients newly implanted with permanent pacemakers and followed-up for 29 ± 18 months. Cardiac events, consisting of cardiac death or heart failure requiring hospitalization, occurred in 22 patients. Kaplan-Meier curves revealed that patients with a high percentage of ventricular pacing (> 90%, n = 101, group H) had a higher incidence of cardiac events than patients with a low percentage of ventricular pacing (< 10%, n = 83, group L) (P = 0.002). In group H, multivariate analysis showed that age (HR: 1.174, 95%CI: 1.066-1.291, P = 0.001), ejection fraction (EF) (HR: 0.898, 95%CI: 0.836-0.964, P = 0.003), QRS duration during cardiac pacing (HR: 1.059, 95%CI: 1.017-1.103, P = 0.006), and existing basal cardiac diseases (HR: 13.080, 95%CI: 2.463-69.479, P = 0.003) were significant predictors of cardiac events, although pacing site had no significant association with prognosis (P = 0.56).Higher age, lower EF, longer QRS duration during cardiac pacing, and existing basal cardiac diseases are associated with poor prognosis in patients with a high percentage of ventricular pacing.