Lanthanide-doped inorganic nanoparticles turn molecular triplet excitons bright.

The generation, control and transfer of triplet excitons in molecular and hybrid systems is of great interest owing to their long lifetime and diffusion length in both solid-state and solution phase systems, and to their applications in light emission1, optoelectronics2,3, photon frequency conversion4,5 and photocatalysis6,7. Molecular triplet excitons (bound electron-hole pairs) are 'dark states' because of the forbidden nature of the direct optical transition between the spin-zero ground state and the spin-one triplet levels8. Hence, triplet dynamics are conventionally controlled through heavy-metal-based spin-orbit coupling9-11 or tuning of the singlet-triplet energy splitting12,13 via molecular design. Both these methods place constraints on the range of properties that can be modified and the molecular structures that can be used. Here we demonstrate that it is possible to control triplet dynamics by coupling organic molecules to lanthanide-doped inorganic insulating nanoparticles. This allows the classically forbidden transitions from the ground-state singlet to excited-state triplets to gain oscillator strength, enabling triplets to be directly generated on molecules via photon absorption. Photogenerated singlet excitons can be converted to triplet excitons on sub-10-picosecond timescales with unity efficiency by intersystem crossing. Triplet exciton states of the molecules can undergo energy transfer to the lanthanide ions with unity efficiency, which allows us to achieve luminescent harvesting of the dark triplet excitons. Furthermore, we demonstrate that the triplet excitons generated in the lanthanide nanoparticle-molecule hybrid systems by near-infrared photoexcitation can undergo efficient upconversion via a lanthanide-triplet excitation fusion process: this process enables endothermic upconversion and allows efficient upconversion from near-infrared to visible frequencies in the solid state. These results provide a new way to control triplet excitons, which is essential for many fields of optoelectronic and biomedical research.

Association between sub-phenotypes identified using latent class analysis and neurological outcomes in patients with out-of-hospital cardiac arrest in Japan.

BACKGROUND: In patients who experience out-of-hospital cardiac arrest (OHCA), it is important to assess the association of sub-phenotypes identified by latent class analysis (LCA) using pre-hospital prognostic factors and factors measurable immediately after hospital arrival with neurological outcomes at 30 days, which would aid in making treatment decisions. METHODS: This study retrospectively analyzed data obtained from the Japanese OHCA registry between June 2014 and December 2019. The registry included a complete set of data on adult patients with OHCA, which was used in the LCA. The association between the sub-phenotypes and 30-day survival with favorable neurological outcomes was investigated. Furthermore, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multivariate logistic regression analysis using in-hospital data as covariates. RESULTS: A total of, 22,261 adult patients who experienced OHCA were classified into three sub-phenotypes. The factor with the highest discriminative power upon patient's arrival was Glasgow Coma Scale followed by partial pressure of oxygen. Thirty-day survival with favorable neurological outcome as the primary outcome was evident in 66.0% participants in Group 1, 5.2% in Group 2, and 0.5% in Group 3. The 30-day survival rates were 80.6%, 11.8%, and 1.3% in groups 1, 2, and 3, respectively. Logistic regression analysis revealed that the ORs (95% CI) for 30-day survival with favorable neurological outcomes were 137.1 (99.4-192.2) for Group 1 and 4.59 (3.46-6.23) for Group 2 in comparison to Group 3. For 30-day survival, the ORs (95%CI) were 161.7 (124.2-212.1) for Group 1 and 5.78 (4.78-7.04) for Group 2, compared to Group 3. CONCLUSIONS: This study identified three sub-phenotypes based on the prognostic factors available immediately after hospital arrival that could predict neurological outcomes and be useful in determining the treatment strategy of patients experiencing OHCA upon their arrival at the hospital.

Naphazoline intoxication managed with minimally invasive cardiac output monitoring.

Naphazoline, a nonspecific alpha-adrenoceptor stimulant, is a potent vasoconstrictor used in nasal sprays, eye drops, and over-the-counter antiseptics. Naphazoline intoxication increases afterload by constricting the peripheral arteries, which can lead to complications including multiple organ failure. Although phentolamine, a nonselective alpha-adrenoceptor antagonist, and nicardipine, a calcium channel blocker, are used for the treatment of naphazoline intoxication, no established administration protocols currently exist. We present the case of a 32-year-old male with depression who ingested 150 mL of an antiseptic containing 0.1% naphazoline (equivalent to 150 mg of naphazoline). Five hours after ingestion, the patient was admitted to hospital exhibiting signs of naphazoline intoxication, such as bradycardia (46 beats/min), blood pressure of 166/122 mmHg, and peripheral cyanosis. We used the FloTrac™/EV1000™ system (Edwards Lifesciences, Irvine, CA, USA), a minimally invasive cardiac output monitoring system, to monitor systemic vascular resistance. The systemic vascular resistance index (SVRI) was elevated (4457 dyne.s/cm5/m2; nomal range: 1970-2390 dyne.s/cm5/m2) upon admission and initial treatment with continuous intravenous infusion of phentolamine led to SVRI normalization within 2 h. With the goal of maintaining SVRI normalization, continuous infusion with nicardipine was then started. At 10 h after treatment initiation, the nicardipine dose peaked at 9 mg/h (1.9 µg/kg/min). Treatment was discontinued 8 h later, and the patient was discharged on the fourth day without sequelae. In conclusion, the use of a minimally invasive cardiac output monitoring system to track vascular resistance can effectively guide the dosing of phentolamine or nicardipine in the treatment of naphazoline intoxication.

Quantum mechanical analysis of excitation energy transfer couplings in photosystem II.

We evaluated excitation energy transfer (EET) coupling (J) between all pairs of chlorophylls (Chls) and pheophytins (Pheos) in the protein environment of photosystem II based on the time-dependent density functional theory with a quantum mechanical/molecular mechanics approach. In the reaction center, the EET coupling between Chls PD1 and PD2 is weaker (|J(PD1/PD2)| = 79 cm-1), irrespective of a short edge-to-edge distance of 3.6 Å (Mg-to-Mg distance of 8.1 Å), than the couplings between PD1 and the accessory ChlD1 (|J(PD1/ChlD2)| = 104 cm-1) and between PD2 and ChlD2 (|J(PD2/ChlD1)| = 101 cm-1), suggesting that PD1 and PD2 are two monomeric Chls rather than a "special pair". There exist strongly coupled Chl pairs (|J| > âˆ¼100 cm-1) in the CP47 and CP43 core antennas, which may be candidates for the red-shifted Chls observed in spectroscopic studies. In CP47 and CP43, Chls ligated to CP47-His26 and CP43-His56, which are located in the middle layer of the thylakoid membrane, play a role in the "hub" that mediates the EET from the lumenal to stromal layers. In the stromal layer, Chls ligated to CP47-His466, CP43-His441, and CP43-His444 mediate the EET from CP47 to ChlD2/PheoD2 and from CP43 to ChlD1/PheoD1 in the reaction center. Thus, the excitation energy from both CP47 and CP43 can always be utilized for the charge-separation reaction in the reaction center.

Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers.

In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron-hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochrome c2 binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1•+ and is stabilized predominantly by charged residues near the Mn4CaO5 cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1 the initial electron donor in PSII.

Effects of Non-Face-to-Face and Noncontact Interventions on Knee Pain and Physical Activity in Older Adults With Knee Osteoarthritis: A Systematic Review and Meta-Analysis.

Increased physical activity is an effective treatment for knee osteoarthritis that causes knee pain. However, due to the coronavirus disease 2019, noncontact and non-face-to-face interventions have increased, but the quality of evidence supporting their effectiveness remains unclear. The purpose of the study was to assess the quality of evidence of the effects of non-face-to-face and noncontact interventions on knee pain and physical activity in older adults with knee osteoarthritis. A meta-analysis was conducted to determine the effects of different intervention methods (education and exercise). The Cochrane Central Register of Controlled Trials, PubMed, Cumulative Index to Nursing and Allied Health Literature, and Physiotherapy Evidence Database were systematically searched. Four randomized controlled trials were included in the analysis. The meta-analysis demonstrated that the educational intervention group was significantly effective, although supportive evidence was low quality. Educational intervention may be effective, but the effects need to be confirmed by higher quality clinical trials.

A self-assembled coordination cage enhances the reactivity of confined amides via mechanical bond-twisting.

Self-assembled coordination cages composed of metal cations and ligands can enhance the hydrolysis of non-covalently trapped amides in mild conditions as demonstrated in recent experiments. Here, we reveal the mechanism that accelerates base-catalyzed amide hydrolysis inside the octahedral coordination cage, by means of a quantum mechanics/molecular mechanics/polarizable continuum model. The calculated activation barrier of the nucleophilic OH- addition to a planar diaryl amide drastically decreases in the cage because of mechanical bond-twisting due to host-guest π-stacking. By contrast, the OH- addition to an N-acylindole, which possesses a twisted amide bond in bulk water, is not enhanced in the cage. Even though the cage hinders OH- collisions with the confined amide, the cage can twist the dihedral angle of the planar amide so as to mimic the transition state of OH- addition.

Triplet Exciton Transfers and Triplet-Triplet Annihilation in Anthracene Derivatives via Direct versus Superexchange Pathways Governed by Molecular Packing.

Triplet exciton transfer (TET) and triplet-triplet annihilations (TTAs) in anthracene derivatives, namely, one of the polymorphs of 9,10-bis(triisopropylsilylethynyl)anthracene (TIPS-ANTp) and 1,2,3,4-tetrafluoro-5,8-bis(trimethylsilylethynyl)anthracene (F4-TMS-ANT), are analyzed theoretically. The electronic couplings for TET and TTA are evaluated by means of the diabatization scheme in conjunction with the time-dependent density functional theory and the multireference second-order Møller-Plesset method. The TET rate is estimated on the basis of Fermi's golden rule considering the Franck-Condon factor of intramolecular modes. TTA is analyzed by means of quantum dynamics calculations with the multiconfiguration time-dependent Hartree method. TET in the cofacially stacked F4-TMS-ANT is faster than that of the slip-stacked TIPS-ANTp. In the anthracene derivatives, a singlet exciton is lower in energy than a pair of triplets. F4-TMS-ANT can exhibit an ultrafast TTA via the superexchange pathway mediated by higher lying charge transfer (CT) states, owing to strong electronic couplings. In contrast, TIPS-ANTp exhibits an inefficient TTA via the direct pathway with a small two-electron coupling. The cofacial stacking decreases the energy gap to the intermediate CT states, thereby facilitating TET and TTA via the superexchange pathway.

Quenching of Singlet Oxygen by Carotenoids via Ultrafast Superexchange Dynamics.

We analyze the quenching mechanism of singlet molecular oxygen (1O2) by carotenoids, namely lycopene, ß-carotene, astaxanthin, and lutein, by means of quantum dynamics calculations and ab initio calculations. The singlet carotenoid (1Car) and 1O2 molecules can form a weakly bound complex via donation of electron density from the highest occupied molecular orbital (HOMO) of the carotenoid to the πg* orbitals of 1O2. The Dexter-type superexchange via charge transfer states (Car•+/O2•-) governs the 1O2 quenching. The Car•+/O2•- states are substantially higher in energy (2-4 eV) than the initial 1Car/1O2 states. The quantum dynamics calculations indicate an ultrafast 1O2 quenching on a timescale of subpicosecond owing to the strong electronic couplings in the carotenoid/O2 complexes. The superexchange mechanism via the Car•+/O2•- states dominates the 1O2 quenching, although the direct two-electron coupling can also play a certain role.

Singlet exciton fission via an intermolecular charge transfer state in coevaporated pentacene-perfluoropentacene thin films.

Singlet exciton fission is a spin-allowed process in organic semiconductors by which one absorbed photon generates two triplet excitons. Theory predicts that singlet fission is mediated by intermolecular charge-transfer states in solid-state materials with appropriate singlet-triplet energy spacing, but direct evidence for the involvement of such states in the process has not been provided yet. Here, we report on the observation of subpicosecond singlet fission in mixed films of pentacene and perfluoropentacene. By combining transient spectroscopy measurements to nonadiabatic quantum-dynamics simulations, we show that direct excitation in the charge-transfer absorption band of the mixed films leads to the formation of triplet excitons, unambiguously proving that they act as intermediate states in the fission process.

Diabatization for Time-Dependent Density Functional Theory: Exciton Transfers and Related Conical Intersections.

Intermolecular exciton transfers and related conical intersections are analyzed by diabatization for time-dependent density functional theory. The diabatic states are expressed as a linear combination of the adiabatic states so as to emulate the well-defined reference states. The singlet exciton coupling calculated by the diabatization scheme includes contributions from the Coulomb (Förster) and electron exchange (Dexter) couplings. For triplet exciton transfers, the Dexter coupling, charge transfer integral, and diabatic potentials of stacked molecules are calculated for analyzing direct and superexchange pathways. We discuss some topologies of molecular aggregates that induce conical intersections on the vanishing points of the exciton coupling, namely boundary of H- and J-aggregates and T-shape aggregates, as well as canceled exciton coupling to the bright state of H-aggregate, i.e., selective exciton transfer to the dark state. The diabatization scheme automatically accounts for the Berry phase by fixing the signs of reference states while scanning the coordinates.

Circularly polarized near-field optical mapping of spin-resolved quantum Hall chiral edge states.

We have successfully developed a circularly polarized near-field scanning optical microscope (NSOM) that enables us to irradiate circularly polarized light with spatial resolution below the diffraction limit. As a demonstration, we perform real-space mapping of the quantum Hall chiral edge states near the edge of a Hall-bar structure by injecting spin polarized electrons optically at low temperature. The obtained real-space mappings show that spin-polarized electrons are injected optically to the two-dimensional electron layer. Our general method to locally inject spins using a circularly polarized NSOM should be broadly applicable to characterize a variety of nanomaterials and nanostructures.

First-Principles Quantum Dynamics of Singlet Fission: Coherent versus Thermally Activated Mechanisms Governed by Molecular π Stacking.

Singlet excitons in π-stacked molecular crystals can split into two triplet excitons in a process called singlet fission that opens a route to carrier multiplication in photovoltaics. To resolve controversies about the mechanism of singlet fission, we have developed a first principles nonadiabatic quantum dynamical model that reveals the critical role of molecular stacking symmetry and provides a unified picture of coherent versus thermally activated singlet fission mechanisms in different acenes. The slip-stacked equilibrium packing structure of pentacene derivatives is found to enhance ultrafast singlet fission mediated by a coherent superexchange mechanism via higher-lying charge transfer states. By contrast, the electronic couplings for singlet fission strictly vanish at the C(2h) symmetric equilibrium π stacking of rubrene. In this case, singlet fission is driven by excitations of symmetry-breaking intermolecular vibrations, rationalizing the experimentally observed temperature dependence. Design rules for optimal singlet fission materials therefore need to account for the interplay of molecular π-stacking symmetry and phonon-induced coherent or thermally activated mechanisms.

[Successful treatment with rituximab in a patient with splenic marginal zone B-cell lymphoma accompanied by cold agglutinin disease].

An 81-year-old man was admitted to our hospital due to dyspnea in July 2008. A physical examination revealed marked splenomegaly, and the results of laboratory tests were as follows: hemoglobin (Hb)=7.0 g/dL, Ret=6.4%, WBC=24,100/µL (Ly: 20,003/µL), indirect bilirubin=3.6 mg/dL, LDH=232 IU/L. The cold agglutinin titer was 1 : 8,192, and a direct antiglobulin test was positive. A PET scan showed abnormal accumulation in the spleen and bone marrow. A bone marrow aspirate examination and biopsy demonstrated diffuse involvement of abnormal lymphocytes that were found to be positive for CD20 and negative for CD5, CD10, and cyclin D1. The immunoglobulin genes were clonally rearranged. Based on these findings, splenic marginal zone B-cell lymphoma (SMZL) associated with cold agglutinin disease (CAD) was diagnosed. Because the patient refused splenectomy, he was treated with four cycles of rituximab therapy (375 mg/kg, once a week). The Hb level and lymphocyte count subsequently normalized and the splenomegaly resolved. One year later, he relapsed and was again treated with rituximab therapy with complete remission. CAD accompanied by SMZL is very rare. Rituximab may be chosen as an alternative and effective therapeutic option in patients with SMZL-particularly those with autoimmune hemolytic anemia.

Clinically significant effects of gait modification on knee pain: A systematic review and meta-analysis.

BACKGROUND: Knee pain is the main symptom of knee osteoarthritis. Walking is effective against knee pain, and some studies have shown that gait modification can also relieve this condition. However, the quality of evidence for the clinically significant effects of gait modification on knee pain has not been examined. OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the level of evidence for the clinically significant effects of gait modification on knee pain and determine if the effects are greater than the minimal clinically important difference (MCID). METHODS: We comprehensively searched electronic databases such as MEDLINE, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, and Cumulative Index to Nursing and Allied Health Literature. Intervention studies with experimental groups who received gait modification and control groups who did not were evaluated. The Grading of Recommendations Assessment, Development and Evaluation system was used to assess the level of evidence. RESULTS: Nine studies met the inclusion criteria. All were included in the systematic review and two in the meta-analysis. Results showed that gait modification have significant effects (p= 0.02), and the quality of evidence was very low. However, several studies have revealed that the effects of gait modification, when used as a foot-focused intervention, were greater than the MCID. CONCLUSIONS: We concluded that there is a lack of high-quality evidence that supports the general efficacy of gait modification. Although based on low-quality evidence, when applied to the foot, it may have clinically significant effects.

Ultrafast charge separation in organic photovoltaics enhanced by charge delocalization and vibronically hot exciton dissociation.

In organic photovoltaics, the mechanism by which free electrons and holes are generated, overcoming the Coulomb attraction, is a currently much debated topic. To elucidate this mechanism at a molecular level, we carried out a combined electronic structure and quantum dynamical analysis that captures the elementary events from the exciton dissociation to the free carrier generation at polymer/fullerene donor/acceptor heterojunctions. Our calculations show that experimentally observed efficient charge separations can be explained by a combination of two effects: First, the delocalization of charges which substantially reduces the Coulomb barrier, and second, the vibronically hot nature of the charge-transfer state which promotes charge dissociation beyond the barrier. These effects facilitate an ultrafast charge separation even at low-band-offset heterojunctions.

Electron-Transfer Route in the Early Oxidation States of the Mn4CaO5 Cluster in Photosystem II.

The electron transfer from the oxygen-evolving Mn4CaO5 cluster to the electron acceptor D1-Tyr161 (TyrZ) is a prerequisite for water oxidation and O2 evolution. Here, we analyzed the electronic coupling in the rate-limiting electron-transfer transitions using a combined quantum mechanical/molecular mechanical/polarizable continuum model approach. In the S0 to S1 transition, the electronic coupling between the electron-donor Mn3(III) and TyrZ is small (2 meV). In contrast, the electronic coupling between the dangling Mn4(III) and TyrZ is significantly large (172 meV), which suggests that the electron transfer proceeds from Mn3(III) to TyrZ via Mn4(III). In the S1 to S2 transition, the electronic coupling between Mn4(III) and TyrZ is also larger (124 meV) than that between Mn1(III) and TyrZ (1 meV), which favors the formation of the open-cubane S2 conformation with Mn4(IV) over the formation of the closed-cubane S2 conformation with Mn1(IV). In the S0 to S1 and S1 to S2 transitions, the Mn4 d-orbital and the TyrZ π-orbital are hybridized via D1-Asp170, which suggests that D1-Asp170 commonly provides a dominant electron-transfer route.

Difference in the Charge-Separation Energetics between Distinct Conformers in the PixD Photoreceptor.

Blue light using flavin (BLUF) domain proteins are photoreceptors in various organisms. The PixD BLUF domain can adopt two conformations, W91out and W91in, with Trp91 either proximal or distal to flavin (FMN). Using a quantum mechanical/molecular mechanical/polarizable continuum model approach, the energetics of charge-separated and biradical states in the two conformations were investigated. In the W91out conformation, the charge-separated state (FMN•-) is more stable than the photoexcited state (FMN*), whereas it is less stable due to an electrostatic repulsive interaction with the Ser28 side chain in the W91in conformation. This leads to a lower activation energy for the charge separation in the W91out conformation, resulting in a faster charge separation compared to that in the W91in conformation. In the W91out conformation, the radical state (FMNH•) is more stable than FMN•- and forms from FMN•-, leading to reorientation of the Gln50 side chain adjacent to FMN and formation of a hydrogen bond between Gln50 and FMN. Subsequently, a signaling state forms through charge recombination. In contrast, in the W91in conformation, FMN•- cannot proceed further, returning to the dark-adapted state, as FMNH• is less stable. Thus, formation of the signaling state exclusively occurs in the W91out conformation.

Childhood Adversities and Psychological Health of Adult Children of Parents with Mental Illness in Japan.

In this study, we seek to clarify whether the present-day experience of psychological distress among adults whose parents suffered from mental illness is related to their childhood experiences of abuse and neglect and their provision of emotional care for their parents during their school-age years. To this end, a web-based cross-sectional study was conducted. A total of 120 participants over the age of 20 who attended a self-help group responded (50% response rate); of these, 94 had a parent diagnosed with a mental illness, and these participants were included for data analysis purposes. Of the 94 respondents, 65 (69.2%) were highly distressed, as measured by a Kessler (K) 6 measure of ≥5. A logistic regression analysis revealed that the experience of providing emotional care for parents during school-age childhood was significantly related to high levels of distress in adulthood (OR = 3.48; 95% CI 1.21-9.96). For children of parents with mental illnesses, the effects of providing emotional care for parents during childhood may include long-term psychological distress. For this reason, mentally ill parents raising children need visiting community nurses or other professionals to provide emotional care on behalf of their children.

Evaluation of the Jichi Medical University diverticular hemorrhage score in the clinical management of acute diverticular bleeding with emergency or elective endoscopy: A pilot study.

BACKGROUND AND AIMS: Emergency endoscopic hemostasis for colonic diverticular bleeding is effective in preventing serious consequences. However, the low identification rate of the bleeding source makes the procedure burdensome for both patients and providers. We aimed to establish an efficient and safe emergency endoscopy system. METHODS: We prospectively evaluated the usefulness of a scoring system (Jichi Medical University diverticular hemorrhage score: JD score) based on our experiences with past cases. The JD score was determined using four criteria: CT evidence of contrast agent extravasation, 3 points; oral anticoagulant (any type) use, 2 points; C-reactive protein ≥1 mg/dL, 1 point; and comorbidity index ≥3, 1 point. Based on the JD score, patients with acute diverticular bleeding who underwent emergency or elective endoscopy were grouped into JD ≥3 or JD <3 groups, respectively. The primary and secondary endpoints were the bleeding source identification rate and clinical outcomes. RESULTS: The JD ≥3 and JD <3 groups included 35 and 47 patients, respectively. The rate of bleeding source identification, followed by the hemostatic procedure, was significantly higher in the JD ≥3 group than in the JD <3 group (77% vs. 23%, p <0.001), with a higher JD score associated with a higher bleeding source identification rate. No significant difference was observed between the groups in terms of clinical outcomes, except for a higher incidence of rebleeding at one-month post-discharge and a higher number of patients requiring interventional radiology in the JD ≥3 group than in the JD <3 group. Subgroup analysis showed that successful identification of the bleeding source and hemostasis contributed to a shorter hospital stay. CONCLUSION: We established a safe and efficient endoscopic scoring system for treating colonic diverticular bleeding. The higher the JD score, the higher the bleeding source identification, leading to a successful hemostatic procedure. Elective endoscopy was possible in the JD <3 group when vital signs were stable.