A dual spin-controlled chiral two-/three-dimensional perovskite artificial leaf for efficient overall photoelectrochemical water splitting.

The oxygen evolution reaction, which involves high overpotential and slow charge-transport kinetics, plays a critical role in determining the efficiency of solar-driven water splitting. The chiral-induced spin selectivity phenomenon has been utilized to reduce by-product production and hinder charge recombination. To fully exploit the spin polarization effect, we herein propose a dual spin-controlled perovskite photoelectrode. The three-dimensional (3D) perovskite serves as a light absorber while the two-dimensional (2D) chiral perovskite functions as a spin polarizer to align the spin states of charge carriers. Compared to other investigated chiral organic cations, R-/S-naphthyl ethylamine enable strong spin-orbital coupling due to strengthened π-π stacking interactions. The resulting naphthyl ethylamine-based chiral 2D/3D perovskite photoelectrodes achieved a high spin polarizability of 75%. Moreover, spin relaxation was prevented by employing a chiral spin-selective L-NiFeOOH catalyst, which enables the secondary spin alignment to promote the generation of triplet oxygen. This dual spin-controlled 2D/3D perovskite photoanode achieves a 13.17% of applied-bias photon-to-current efficiency. Here, after connecting the perovskite photocathode with L-NiFeOOH/S-naphthyl ethylamine 2D/3D photoanode in series, the resulting co-planar water-splitting device exhibited a solar-to-hydrogen efficiency of 12.55%.

Stable water splitting using photoelectrodes with a cryogelated overlayer.

Hydrogen production techniques based on solar-water splitting have emerged as carbon-free energy systems. Many researchers have developed highly efficient thin-film photoelectrochemical (PEC) devices made of low-cost and earth-abundant materials. However, solar water splitting systems suffer from short lifetimes due to catalyst instability that is attributed to both chemical dissolution and mechanical stress produced by hydrogen bubbles. A recent study found that the nanoporous hydrogel could prevent the structural degradation of the PEC devices. In this study, we investigate the protection mechanism of the hydrogel-based overlayer by engineering its porous structure using the cryogelation technique. Tests for cryogel overlayers with varied pore structures, such as disconnected micropores, interconnected micropores, and surface macropores, reveal that the hydrogen gas trapped in the cryogel protector reduce shear stress at the catalyst surface by providing bubble nucleation sites. The cryogelated overlayer effectively preserves the uniformly distributed platinum catalyst particles on the device surface for over 200 h. Our finding can help establish semi-permanent photoelectrochemical devices to realize a carbon-free society.

Core-Shell Perovskite Quantum Dots for Highly Selective Room-Temperature Spin Light-Emitting Diodes.

Circularly polarized light (CPL) is a crucial light source with a wide variety of potential applications such as magnetic recording, and 3D display. Here, core-shell heterostructured perovskite quantum dots (QDs) for room-temperature spin-polarized light-emitting diodes (spin-LEDs) are developed. Specifically, a 2D chiral perovskite shell is deposited onto the achiral 3D inorganic perovskite (CsPbBr3 ) core. Owing to the chiral-induced spin selectivity effect, the spin state of the injected charge carriers is biased when they are transmitted through the 2D chiral shell. The spin-controlled carriers then radiatively recombine inside the CsPbBr3 emissive core, resulting in CPL emission. It is demonstrated that the (R)- and (S)-1-(2-(naphthyl)ethylamine) (R-/S-NEA) 2D chiral cations enhance the spin polarization degree due to their strong chiroptical properties. Systematical defect analyses confirm that 2D chiral cations (i.e., R-/S-NEA) successfully passivate halide vacancies at the surface of the CsPbBr3 QDs, thereby attaining a high photoluminescence quantum yield of 78%. Moreover, the spin-LEDs prepared with core-shell QDs achieve a maximum external quantum efficiency of 5.47% and circularly polarized electroluminescence with a polarization degree (PCP-EL ) of 12% at room temperature. Finally, various patterns fabricated by inkjet printing the core-shell QDs emit strong CPL, highlighting their potential as an emitter for next-generation displays.

Chirality-Induced Spin Selectivity of Chiral 2D Perovskite Enabling Efficient Spin-Dependent Oxygen Evolution Reaction.

The sluggish and complex multi-step oxygen evolution reaction remains an obstacle to bias-free photoelectrochemical water-splitting systems. Several theoretical studies have suggested that spin-aligned intermediate radicals can significantly enhance the kinetic rates for oxygen generation. Herein, it is reported that the chirality-induced spin selectivity phenomena can become an impressive approach by adopting chiral 2D organic-inorganic hybrid perovskites as a spin-filtering layer on the photoanode. This chiral 2D perovskite-based water-splitting device achieves enhanced oxygen evolution performance with a reduced overpotential of 0.14 V, high fill factor, and 230% increased photocurrent compared to a device without a spin-filtering layer. Moreover, combined with a superhydrophobic patterning strategy, this device realizes excellent operational stability by sustaining ≈90% of the initial photocurrent, even after 10 h.

Unraveling chirality transfer mechanism by structural isomer-derived hydrogen bonding interaction in 2D chiral perovskite.

In principle, the induced chirality of hybrid perovskites results from symmetry-breaking within inorganic frameworks. However, the detailed mechanism behind the chirality transfer remains unknown due to the lack of systematic studies. Here, using the structural isomer with different functional group location, we deduce the effect of hydrogen-bonding interaction between two building blocks on the degree of chirality transfer in inorganic frameworks. The effect of asymmetric hydrogen-bonding interaction on chirality transfer was clearly demonstrated by thorough experimental analysis. Systematic studies of crystallography parameters confirm that the different asymmetric hydrogen-bonding interactions derived from different functional group location play a key role in chirality transfer phenomena and the resulting spin-related properties of chiral perovskites. The methodology to control the asymmetry of hydrogen-bonding interaction through the small structural difference of structure isomer cation can provide rational design paradigm for unprecedented spin-related properties of chiral perovskite.

Association between Novel Hematological Indices and Measures of Disease Activity in Patients with Rheumatoid Arthritis.

Background and Objectives: Hematological indices have been known to be available markers used for evaluating disease activity in rheumatoid arthritis (RA). This study serves to verify the association between four different hematological indices and disease activity measures in patients with RA. Materials and Methods: The study included 257 female RA patients and 71 age-matched female controls. Four hematological indices, namely systemic immune-inflammation index (SII), neutrophil-to-hemoglobin and lymphocyte (NHL) score, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR), were evaluated. Composite measures of RA included Disease Activity Score 28 joints (DAS28), the simplified disease activity index (SDAI), and the clinical disease activity index (CDAI). Results: Patients with RA showed statistically higher SII, NHL score, NLR, and PLR compared with controls. SII and NHL score were significantly associated with DAS28 erythrocyte sedimentation rate (DAS28-ESR), DAS28 C-reactive protein (DAS28-CRP), CDAI, and SDAI, whereas NLR was related to DAS28-CRP, CDAI, and SDAI. SII, NHL score, and NLR tended to increase as disease activity based on DAS28-ESR, DAS28-CRP, and CDAI worsened. In the analysis using receiver operating characteristic curve of hematological indices for diagnostic accuracy, the area under the curve was 0.703 (95% confidence interval, CI 0.637−0.769, p < 0.001) for SII and 0.705 (95% CI 0.639−0.770, p < 0.001) for NHL score, which showed acceptable potential for the diagnosis of RA. Four hematological indices showed weak potential for the detection of remission. Conclusions: The present study results showed that SII and NHL scores might be useful markers that adequately reflect disease activity and lead to more accurate diagnosis in RA.

Tailoring the Time-Averaged Structure for Polarization-Sensitive Chiral Perovskites.

Chiral perovskites have emerged as promising candidates for polarization-sensing materials. Despite their excellent chiroptical properties, the nature of their multiple-quantum-well structures is a critical hurdle for polarization-based and spintronic applications. Furthermore, as the origin of chiroptical activity in chiral perovskites is still illusive, the strategy for simultaneously enhancing the chiroptical activity and charge transport has not yet been reported. Here, we demonstrated that incorporating a Lewis base into the lattice can effectively tune the chiroptical response and electrical properties of chiral perovskites. Through solid-state nuclear magnetic resonance spectroscopic measurements and theoretical calculations, it was demonstrated that the material property manipulation resulted from the change in the time-averaged structure induced by the Lewis base. Finally, as a preliminary proof of concept, a vertical-type circularly polarized light photodetector based on chiral perovskites was developed, exhibiting an outstanding performance with a distinguishability of 0.27 and a responsivity of 0.43 A W-1.

Elucidating the origin of chiroptical activity in chiral 2D perovskites through nano-confined growth.

Chiral perovskites are being extensively studied as a promising candidate for spintronic- and polarization-based optoelectronic devices due to their interesting spin-polarization properties. However, the origin of chiroptical activity in chiral perovskites is still unknown, as the chirality transfer mechanism has been rarely explored. Here, through the nano-confined growth of chiral perovskites (MBA2PbI4(1-x)Br4x), we verified that the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites. Based on this understanding, we observed remarkable asymmetry behavior (absorption dissymmetry of 2.0 × 10-3 and anisotropy factor of photoluminescence of 6.4 × 10-2 for left- and right-handed circularly polarized light) in nanoconfined chiral perovskites even at room temperature. Our findings suggest that electronic interactions between building blocks should be considered when interpreting the chirality transfer phenomena and designing hybrid materials for future spintronic and polarization-based devices.

Universal Bifacial Stamping Approach Enabling Reverse-Graded Ruddlesden-Popper 2D Perovskite Solar Cells.

Quasi 2D perovskite solar cells (PSCs) are promising light absorbers that overcome the inherent instabilities of 3D perovskites. High-performance and stable 2D PSCs require careful control over the crystallographic orientation and phase distribution. This study introduces a simple and universal bifacial stamping method to obtain highly oriented perovskite crystals with a reverse-graded structure, where the low-n-value 2D perovskite phases are located mainly at the film surfaces. Bifacial stamping of 3D perovskite films atop the 2D films enables incorporation of 2D spacer cations into the 3D film surfaces, forming reverse-graded quasi-2D perovskite films. During stamping, suppressed evaporation of the precursor solvent induces heterogeneous nucleation from the contact interface between the 2D and 3D films, resulting in well-crystallized perovskite films having out-of-plane alignments with respect to the substrate. Thus, a highly oriented and reverse-graded quasi-2D perovskite with an average n value of 18 is obtained with power conversion efficiency exceeding 17% and high open-circuit voltage of 1.11 V for iso-butylammonium (iso-BA)-based (iso-BA2 MAn -1 Pbn I3 n +1 ) PSCs. The unencapsulated device retains 92% of its initial efficiency after aging at 40 ± 5% relative humidity for 1200 h. This work provides a new strategy for fabricating highly oriented and phase-controlled quasi-2D PSCs.

Role of tenofovir disoproxil fumarate in prevention of perinatal transmission of hepatitis B virus from mother to child: a systematic review and meta-analysis.

BACKGROUND/AIMS: To prevent the perinatal transmission of hepatitis B virus (HBV) from mother to child, administration of an antiviral agent during pregnancy has been attempted in women who are either hepatitis B e antigen positive or have a high viral load. In this systematic review and meta-analysis with randomized controlled trials, we analyzed the efficacy and safety of tenofovir disoproxil fumarate (TDF) in preventing the perinatal transmission of HBV in pregnant women who have high HBV DNA titers. METHODS: Multiple comprehensive databases (PubMed, EMBASE, and Cochrane databases) were searched for studies evaluating the efficacy of TDF for the prevention of perinatal transmission of HBV. RESULTS: Two studies (one open label study and one double blind study) were included and analyzed. Intention-to-treat analysis (527 pregnancies) showed that the preventive effect of TDF was not significant (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.13 to 2.17; p = 0.38, I2 = 81%). However, the per-protocol analysis showed that TDF significantly reduced perinatal transmission (OR, 0.10; 95% CI, 0.01 to 0.77; p = 0.03, I2 = 0%). There was no significant difference between the TDF group and the control group with respect to maternal and fetal safety outcomes. CONCLUSION: In pregnant women who have high HBV DNA titers, TDF can reduce the perinatal transmission from mother to child without significant adverse events.

Partial Virological Response after 2 Years of Entecavir Therapy Increases the Risk of Hepatocellular Carcinoma in Patients with Hepatitis B Virus-Associated Cirrhosis.

Background/Aims: : The clinical significance of partial virological response (PVR) in patients undergoing antiviral therapy is not well known. This study investigated whether PVR after 2 years of entecavir (ETV) therapy is associated with hepatocellular carcinoma (HCC) development in cirrhotic patients. Methods: A total of 472 naïve patients with hepatitis B virus (HBV)-associated cirrhosis who were treated with ETV for at least 2 years were retrospectively enrolled. Clinical characteristics, laboratory data, PVR, and noninvasive fibrosis markers (aspartate aminotransferase to platelet ratio and FIB-4 index) at 2 years after ETV commencement were analyzed for HCC risk. Results: After excluding those who developed HCC within 2 years of ETV therapy, 359 patients (mean age, 51±10 years; male 64.3%) were examined. During a median follow-up of 82 months, 80 patients developed HCC. In the univariate analysis, older age (hazard ratio [HR], 1.056; p<0.001), PVR (HR, 2.536; p=0.002), higher aspartate aminotransferase (HR, 1.018; p=0.005), lower albumin level (HR, 0.463; p<0.001), lower platelet count (HR, 0.993; p=0.01), and higher FIB-4 index (HR, 1.141; p<0.001) at 2 years after ETV commencement were risk factors for HCC. In the multivariate analysis, older age (HR, 1.046; 95% confidence interval [CI], 1.022 to 1.072; p<0.001), PVR (HR, 2.358; 95% CI, 1.310 to 4.245; p=0.004), and higher FIB-4 index (HR, 1.103; 95% CI, 1.035 to 1.177; p=0.003) were independent risk factors. Conclusions: PVR and higher FIB-4 index after 2 years of ETV therapy were independent risk factors for HCC. Therefore, efforts to accomplish a complete virological response and reduce the FIB-4 index should be made.

Underlying nonalcoholic fatty liver disease is a significant factor for breast cancer recurrence after curative surgery.

Breast cancer is the most common cancer among women worldwide, and it is a main cause of death in women. As with breast cancer, metabolic components are important risk factors for the development of nonalcoholic fatty liver disease (NAFLD). In this retrospective cohort study, we aimed to determine the prevalence of NAFLD in patients with breast cancer and the impact of NAFLD on the prognosis of breast cancer.Patients with breast cancer were enrolled in the study from January 2007 to June 2017. Hepatic steatosis was evaluated through non-enhanced computed tomography scan by measuring Hounsfield Units in the liver and spleen, respectively; 123 healthy controls who underwent non-enhanced computed tomography scan were also analyzed.The prevalence of NAFLD in patients with breast cancer was 15.8% (251/1587), which was significantly higher than in healthy controls (8.9%, 11/123) (P = .036). Overall survival did not significantly differ between the groups with and without NAFLD (P = .304). However, recurrence-free survival was significantly higher in patients without NAFLD than in those with NAFLD (P = .009). Among breast cancer patients receiving endocrine treatment, the NAFLD group showed a higher cumulative incidence of significant liver injury than the group without NAFLD (P < .001).The prevalence of NAFLD in patients with breast cancer is significantly higher than in healthy controls. Moreover, breast cancer patients with NAFLD showed poorer prognosis in terms of recurrence. Therefore, diagnostic evaluation for NALFD is important in managing patients with breast cancer.

Korean rheumatology workforce from 1992 to 2015: current status and future demand.

BACKGROUND/AIMS: Rheumatology in Korea has rapidly advanced in the 24 years since the subspecialty board certification program was established in 1992. The objective of this investigation was to analyze the distribution of rheumatology practices in Korea in order to better understand the rheumatology workforce. METHODS: Using a membership list from the Korean College of Rheumatology (KCR), we obtained information on practicing rheumatologists. We mapped the ratio of rheumatologists to the general population and to patients with rheumatologic disease using data from Statistics Korea and the 2015 Health Insurance Review & Assessment Service (HIRA). RESULTS: In the 16 administrative districts of Korea in 2015, there were 311 practicing rheumatologists on the list of KCR members. There were 218 members practicing in metropolitan areas and 93 members in the provinces. The mean number of rheumatologists per 100,000 people was 0.60, with 0.33/100,000 in the provinces, but 0.92/100,000 in metropolitan areas, a 2.7-fold difference. The number of rheumatologists per 100,000 patients with chronic rheumatic disease was 17.21 in metropolitan areas but 6.57 in the provinces, according to 2015 HIRA data. This geographic maldistribution emerged as a problem; indeed, the regional disparity in the distribution of Korean rheumatologists was striking when compared to the published medical professional distribution in 2014. CONCLUSION: Because of the uneven distribution of rheumatologists, it is likely that some patients with chronic rheumatic conditions have limited access to rheumatology care. Thus, a policy-based approach is needed to alleviate this disparity.

Hepatic resection compared to chemoembolization in intermediate- to advanced-stage hepatocellular carcinoma: A meta-analysis of high-quality studies.

According to the American Association for the Study of Liver Diseases (AASLD) treatment guidelines for hepatocellular carcinoma (HCC), the role of surgery has been expanded beyond the Barcelona Clinic Liver Cancer (BCLC) algorithm. We compared primary hepatectomy (PH) with transarterial chemoembolization (TACE) in patients with intermediate- to advanced-stage (BCLC stage B/C) HCC to determine the current evidence. Through a database search, we included 18 high-quality studies (one randomized controlled trial [RCT], five propensity-score matching nonrandomized comparative trials [NRCTs], and 12 NRCTs) that compared survival outcomes of 5,986 patients after PH and TACE. We found significant survival benefits for PH over TACE in BCLC stage B/C patients (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.51-0.67; P < 0.00001; I2 = 84%). According to the BCLC, both stage B and stage C patients showed significantly better overall survival (OS) for PH compared to TACE (HR, 0.53; 95% CI, 0.43-0.65; P < 0.00001; I2 = 77%; HR, 0.67; 95% CI, 0.59-0.77; P < 0.00001; I2 = 79%, respectively). Five-year survival rates for PH were significantly higher than those for TACE in BCLC stage B/C, stage B, and BCLC stage C patients (odds ratio [OR], 2.71, 2.77, and 3.03, respectively; all P < 0.00001). Survival benefits persisted across subgroup, sensitivity, and metaregression analyses; interstudy heterogeneity remained constant. CONCLUSION: This meta-analysis suggests that surgical resection provides survival benefits in patients with intermediate- to advanced-stage HCC. The evidence found herein may assist in the choice of treatment modality based on diverse definitions of operability. (Hepatology 2018).