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.

Ultrathin Crystalline Silicon Nano and Micro Membranes with High Areal Density for Low-Cost Flexible Electronics.

Ultrathin crystalline silicon is widely used as an active material for high-performance, flexible, and stretchable electronics, from simple passive and active components to complex integrated circuits, due to its excellent electrical and mechanical properties. However, in contrast to conventional silicon wafer-based devices, ultrathin crystalline silicon-based electronics require an expensive and rather complicated fabrication process. Although silicon-on-insulator (SOI) wafers are commonly used to obtain a single layer of crystalline silicon, they are costly and difficult to process. Therefore, as an alternative to SOI wafers-based thin layers, here, a simple transfer method is proposed for printing ultrathin multiple crystalline silicon sheets with thicknesses between 300 nm to 13 µm and high areal density (>90%) from a single mother wafer. Theoretically, the silicon nano/micro membrane can be generated until the mother wafer is completely consumed. In addition, the electronic applications of silicon membranes are successfully demonstrated through the fabrication of a flexible solar cell and flexible NMOS transistor arrays.

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.

Complex and irregular heart rate dynamics in fetuses compromised by maternal anemia as a high-risk pregnancy.

AIM: To examine how complex and irregular fetal heart rate (FHR) dynamics differ between fetuses of normal pregnancies and those of pregnancies complicated by maternal anemia (MA), and to place this in the context of high-risk pregnancies. METHODS: Our study population consisted of 97 pregnant women affected by MA, 118 affected by pregnancy-induced hypertension (PIH), 88 affected by gestational diabetes mellitus (GDM), 53 with preterm premature rupture of membranes (pPROM), and 356 normal pregnancies as controls. We calculated approximate entropy (ApEn), sample entropy (SampEn), and correlation dimension (CD) to quantify irregularity and the chaotic dynamics of each FHR time series. RESULTS: The ApEn in the fetuses of the MA and PIH groups was significantly lower than that of the normal controls (P<0.05). The SampEn was significantly lower in the high-risk groups, except for the pPROM group, than in the normal controls (P<0.05). The CD in the PIH and severe MA groups was significantly lower than that of the normal controls (P<0.05, respectively). In the MA group, the dynamic indices showed a highly significant positive correlation with hemoglobin (Hb) levels (P<0.0001). CONCLUSION: The decreased complexity and/or irregularity in the FHR from pregnancies with MA may reflect abnormalities in the complex, integrated cardiovascular control. The irregularity and complexity of the FHR increased together with Hb levels in pregnancies with MA. Our data suggest that the integrity of the nervous system in the fetuses compromised by severe MA might result directly in adverse outcomes.

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%.

Evaluation of Instantaneous Wave-Free Ratio and Fractional Flow Reserve in Severe Aortic Valve Stenosis.

BACKGROUND: The optimal functional evaluation of coronary artery stenosis in patients with severe aortic stenosis (AS) has not been established. The objective of the study was to evaluate the instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with and without severe AS. METHODS: We retrospectively investigated 395 lesions in 293 patients with severe AS and 2257 lesions in 1882 patients without severe AS between 2010 and 2022 from a subgroup of the Interventional Cardiology Research In-Cooperation Society FFR Registry. All patients had FFR values, and iFR was analyzed post hoc using dedicated software only in lesions with adequate resting pressure curves (311 lesions in patients with severe AS and 2257 lesions in patients with nonsevere AS). RESULTS: The incidence of iFR ≤0.89 was 66.6% and 31.8% (P<0.001), while the incidence of FFR ≤0.80 was 45.3% and 43.9% (P=0.60) in the severe AS group and the nonsevere AS group, respectively. In the severe AS group, most lesions (95.2%) with iFR >0.89 had FFR >0.80, while 36.2% of lesions with iFR ≤0.89 had FFR >0.80. During a median follow-up of 2 years, FFR ≤0.80 was significantly associated with deferred lesion failure (adjusted hazard ratio, 2.71 [95% CI, 1.08-6.80]; P=0.034), while iFR ≤0.89 showed no prognostic value (adjusted hazard ratio, 1.31 [95% CI, 0.47-3.60]; P=0.60) in the severe AS group. Lesions with iFR ≤0.89 and FFR >0.80, in particular, were not associated with a higher rate of deferred lesion failure at 3 years compared with lesions with iFR >0.89 (15.4% versus 17.0%; P=0.58). CONCLUSIONS: This study suggested that FFR appears to be less affected by the presence of severe AS and is more associated with prognosis. iFR may overestimate the functional severity of coronary artery disease without prognostic significance, yet it can be useful for excluding significant stenosis in patients with severe AS.

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.

Impact of Target Lesion Revascularization on Long-Term Mortality After Percutaneous Coronary Intervention for Left Main Disease.

BACKGROUND: Although target lesion revascularization (TLR) after percutaneous coronary intervention (PCI) for unprotected left main coronary artery (LMCA) disease is not rare, its timing of occurrence and prognostic impact on long-term mortality is uncertain. OBJECTIVES: This study sought to investigate TLR incidence over time and its impact on mortality after PCI with drug-eluting stents (DES) for LMCA disease. METHODS: Using a pooled data from 4 multicenter observational registries (IRIS-DES [Interventional Cardiology Research Incorporation Society-Drug-Eluting Stents], IRIS-MAIN [Interventional Cardiology Research Incorporation Society-Left MAIN Revascularization], MAIN-COMPARE [Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty Versus Surgical Revascularization], and PRECOMBAT [PREmier of Randomized COMparison of Bypass Surgery versus AngioplasTy Using Drug-Eluting Stent in Patients with Left Main Coronary Artery Disease]), we evaluated 1,397 patients with LMCA disease treated with DES and available long-term mortality data. The association between TLR and the 10-year risk of mortality was examined by multivariable Cox proportional hazards regression, with TLR as a time-varying covariate. RESULTS: During maximum follow-up of 10 years (median 6.8 years), TLR occurred in 118 patients and its 10-year cumulative incidence was 10.8%. TLR mostly occurred within 2 years after initial PCI and decreased over time: early-stage TLR (within 2 years) in 73 (61.9%) patients and late-stage TLR (beyond 2 years) in 45 (38.1%) patients. Among all TLR patients, 23 patients underwent coronary artery bypass grafting and 95 underwent repeat PCI. In the time-varying multivariable Cox model, the presence of TLR was not significantly associated with an increased risk of mortality (adjusted HR: 0.90; 95% CI: 0.50-1.63; P = 0.73). CONCLUSIONS: Although the incidence of ischemia-driven TLR was mostly common within 2 years after left main PCI, TLR occurred steadily during the 10-year follow-up period. However, given that such patients were optimally revascularized, the prognostic impact of TLR on mortality was not substantial. (Evaluation of the First, Second, and New Drug-Eluting Stents in Routine Clinical Practice [IRIS-DES]; NCT01186133; Observational Study for Left Main Disease Treatment [IRIS-MAIN]; NCT01341327; Ten-Year Outcomes of Stents Versus Coronary-Artery Bypass Grafting for Left Main Coronary Artery Disease [MAIN COMPARE]; NCT02791412; Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease [PRECOMBAT]; NCT00422968).

Surveillance Stress Testing After Percutaneous Intervention for Patients With Multivessel or Left Main Coronary Disease.

BACKGROUND: The optimal surveillance strategy after percutaneous coronary intervention (PCI) for high-risk patients with multivessel or left main coronary artery disease (CAD) remains uncertain. OBJECTIVES: This study aims to determine the prognostic role of routine functional testing in patients with multivessel or left main CAD who underwent PCI. METHODS: The POST-PCI (Pragmatic Trial Comparing Symptom-Oriented Versus Routine Stress Testing in High-Risk Patients Undergoing Percutaneous Coronary Intervention) trial randomized high-risk PCI patients to routine functional testing at 1 year or standard care alone during follow-up. This analysis focused on participants with multivessel or left main CAD. The primary outcome was a composite of death from any cause, myocardial infarction, or hospitalization for unstable angina at 2 years. RESULTS: Among 1,706 initially randomized patients, 1,192 patients with multivessel (n = 833) or left main (n = 359) were identified, with 589 in the functional testing group and 603 in the standard care group. Two-year incidences of primary outcome were similar between the functional testing group and the standard care group (6.2% vs 5.7%, respectively; HR: 1.09; 95% CI: 0.68-1.74; P = 0.73). This trend persisted in both groups of multivessel (6.2% vs 5.7%; HR: 1.09; 95% CI: 0.62-1.89; P = 0.78) and left main disease (6.2% vs 5.7%; HR: 1.09; 95% CI: 0.46-2.56; P = 0.85) (P for interaction = 0.90). Routine surveillance functional testing was associated with increased rates of invasive angiography and repeat revascularization beyond 1 year. CONCLUSIONS: In high-risk patients with multivessel or left main CAD who underwent PCI, there was no incremental clinical benefit from routine surveillance functional-testing compared with standard care alone during follow-up. (Pragmatic Trial Comparing Symptom-Oriented Versus Routine Stress Testing in High-Risk Patients Undergoing Percutaneous Coronary Intervention [POST-PCI]; NCT03217877).

Bi2 S3 -Cu3 BiS3 Mixed Phase Interlayer for High-Performance Cu3 BiS3 -Photocathode for 2.33% Unassisted Solar Water Splitting Efficiency.

To realize practical solar hydrogen production, a low-cost photocathode with high photocurrent density and onset potential should be developed. Herein, an efficient and stable overall photoelectrochemical tandem cell is developed with a Cu3 BiS3 -based photocathode. By exploiting the crystallographic similarities between Bi2 S3 and Cu3 BiS3 , a one-step solution process with two sulfur sources is used to prepare the Bi2 S3 -Cu3 BiS3 blended interlayer. The elongated Bi2 S3 -Cu3 BiS3 mixed-phase 1D nanorods atop a planar Cu3 BiS3 film enable a high photocurrent density of 7.8 mA cm-2 at 0 V versus the reversible hydrogen electrode, with an onset potential of 0.9 VRHE . The increased performance over the single-phase Cu3 BiS3 thin-film photocathode is attributed to the enhanced light scattering and charge collection through the unique 1D nanostructure, improved electrical conductivity, and better band alignment with the n-type CdS layer. A solar-to-hydrogen efficiency of 2.33% is achieved under unassisted conditions with a state-of-the-art Mo:BiVO4 photoanode, with excellent stability exceeding 21 h.

Fetal heart rate regresses toward the mean in the third trimester.

The purpose of this study was to investigate the feasibility of different fetal heart rate (FHR) ranges in the nonstress test (NST) and to better understand the meaning of mild bradycardia and/or tachycardia without non-reassuring patterns. We employed the heredity to show that mild bradycardia (100-119 beats per minute, bpm) and mild tachycardia (161-180 bpm) regressed to the normal FHR range (120-160 bpm). We used linear regression to analyze FHR data from FHR tracings recorded 10 min before (NST, as the predictor) and 10 min after vibroacoustic stimulation testing (as the dependent variable). Acceleration for 15 bpm-15 seconds (Acc1515) and deceleration for 15 bpm-15 seconds (Dec1515) in the NST were also analyzed for each group. The slope of the best-fit line was the largest in the mild bradycardia group and the smallest in the normal range group. Dec1515 was most prominent in mild tachycardia and both the mild bradycardia and tachycardia groups regressed towards the mean FHR range. Therefore, we propose that both mild bradycardia and tachycardia of FHR in non-acute situations (range between 100 and 180 bpm) are not regarded a pathologic signal for clinical use.

Comprehensive Assessment of Acute Isolated or Prominent Dysarthria in the Emergency Department: A Neuro-Emergency Expert's Experience beyond Stroke.

We investigated the clinical characteristics, neuroimaging findings, and final diagnosis of patients with acute isolated or prominent dysarthria who visited the emergency department (ED) between 1 January 2020 and 31 December 2021. Of 2028 patients aged ≥ 18 years with neurologic symptoms treated by a neuro-emergency expert, 75 with acute isolated or predominant dysarthria within 1 week were enrolled. Patients were categorized as having isolated dysarthria (n = 28, 37.3%) and prominent dysarthria (n = 47, 62.7%). The causes of stroke were acute ischemic stroke (AIS) (n = 37, 49.3%), transient ischemic attack (TIA) (n = 14, 18.7%), intracerebral hemorrhage (n = 1, 1.3%), and non-stroke causes (n = 23, 30.7%). The most common additional symptoms were gait disturbance or imbalance (n = 8, 15.4%) and dizziness (n = 3, 13.0%) in the stroke and non-stroke groups, respectively. The isolated dysarthria group had a higher rate of TIA (n = 7, 38.9%), single and small lesions (n = 10, 83.3%), and small-vessel occlusion in Trial of Org 101072 in acute stroke treatment (n = 8, 66.7%). Acute isolated or prominent dysarthria in the ED mostly presented as clinical symptoms of AIS, but other non-stroke and medical causes were not uncommon. In acute dysarthria with ischemic stroke, multiple territorial and small and single lesions are considered a cause.

Experience of a Neuro-Emergency Expert in the Emergency Department during One Year of the COVID-19 Pandemic.

We aimed to evaluate the overall clinical characteristics of patients treated by a neuro-emergency expert dedicated to the emergency department (ED) as an attending neurologist during the COVID-19 pandemic. We included adult patients who visited the ED between 1 January and 31 December 2020 and were treated by a neuro-emergency expert. We retrospectively obtained and analyzed the data on patients' clinical characteristics and outcome. The neuro-emergency expert treated 1155 patients (mean age, 62.9 years). The proportion of aged 18-40 years was the lowest, and the most common modes of arrival were public ambulance (50.6%) and walk-in (42.3%). CT and MRI examinations were performed in 94.4 and 33.1% of cases, respectively. The most frequent complaints were dizziness (31.8%), motor weakness (24.2%), and altered mental status (15.8%). The ED diagnoses were acute ischemic stroke (19.8%), benign paroxysmal positional vertigo (14.2%), vestibular neuritis (9.9%), and seizure (8.8%). The mean length of stay in the ED was 207 min. Of the patients, 55.0% were admitted to the hospital, and 41.8% were discharged for outpatient follow-up. Despite the longer stay and the complexity and difficulty of neurological diseases during the COVID-19 pandemic, the accurate diagnosis and treatment provided by a neuro-emergency expert can be presented as a good model in the ED.

Validation and modification of HEART score components for patients with chest pain in the emergency department.

OBJECTIVE: This study aimed to clarify the relative prognostic value of each History, Electrocardiography, Age, Risk Factors, and Troponin (HEART) score component for major adverse cardiac events (MACE) within 3 months and validate the modified HEART (mHEART) score. METHODS: This study evaluated the HEART score components for patients with chest symptoms visiting the emergency department from November 19, 2018 to November 19, 2019. All components were evaluated using logistic regression analysis and the scores for HEART, mHEART, and Thrombolysis in Myocardial Infarction (TIMI) were determined using the receiver operating characteristics curve. RESULTS: The patients were divided into a derivation (809 patients) and a validation group (298 patients). In multivariate analysis, age did not show statistical significance in the detection of MACE within 3 months and the mHEART score was calculated after omitting the age component. The areas under the receiver operating characteristics curves for HEART, mHEART and TIMI scores in the prediction of MACE within 3 months were 0.88, 0.91, and 0.83, respectively, in the derivation group; and 0.88, 0.91, and 0.81, respectively, in the validation group. When the cutoff value for each scoring system was determined for the maintenance of a negative predictive value for a MACE rate >99%, the mHEART score showed the highest sensitivity, specificity, positive predictive value, and negative predictive value (97.4%, 54.2%, 23.7%, and 99.3%, respectively). CONCLUSION: Our study showed that the mHEART score better detects short-term MACE in high-risk patients and ensures the safe disposition of low-risk patients than the HEART and TIMI scores.

Application of convolutional neural networks for distal radio-ulnar fracture detection on plain radiographs in the emergency room.

OBJECTIVE: Recent studies have suggested that deep-learning models can satisfactorily assist in fracture diagnosis. We aimed to evaluate the performance of two of such models in wrist fracture detection. METHODS: We collected image data of patients who visited with wrist trauma at the emergency department. A dataset extracted from January 2018 to May 2020 was split into training (90%) and test (10%) datasets, and two types of convolutional neural networks (i.e., DenseNet-161 and ResNet-152) were trained to detect wrist fractures. Gradient-weighted class activation mapping was used to highlight the regions of radiograph scans that contributed to the decision of the model. Performance of the convolutional neural network models was evaluated using the area under the receiver operating characteristic curve. RESULTS: For model training, we used 4,551 radiographs from 798 patients and 4,443 radiographs from 1,481 patients with and without fractures, respectively. The remaining 10% (300 radiographs from 100 patients with fractures and 690 radiographs from 230 patients without fractures) was used as a test dataset. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DenseNet-161 and ResNet-152 in the test dataset were 90.3%, 90.3%, 80.3%, 95.6%, and 90.3% and 88.6%, 88.4%, 76.9%, 94.7%, and 88.5%, respectively. The area under the receiver operating characteristic curves of DenseNet-161 and ResNet-152 for wrist fracture detection were 0.962 and 0.947, respectively. CONCLUSION: We demonstrated that DenseNet-161 and ResNet-152 models could help detect wrist fractures in the emergency room with satisfactory performance.

Crystal Facet-Controlled Efficient SnS Photocathodes for High Performance Bias-Free Solar Water Splitting.

To achieve a high solar-to-hydrogen (STH) conversion efficiency, delicate strategies toward high photocurrent together with sufficient onset potential should be developed. Herein, an SnS semiconductor is reported as a high-performance photocathode. Use of proper sulfur precursor having weak dipole moment allows to obtain high-quality dense SnS nanoplates with enlarged favorable crystallographic facet, while suppressing inevitable anisotropic growth. Furthermore, the introducing Ga2 O3 layer between SnS and TiO2 in SnS photocathodes efficiently improves the charge transport kinetics without charge trapping. The SnS photocathode reveals the highest photocurrent density of 28 mA cm-2 at 0 V versus the reversible hydrogen electrode. Overall solar water splitting is demonstrated for the first time by combining the optimized SnS photocathode with a Mo:BiVO4 photoanode, achieving a STH efficiency of 1.7% and long-term stability of 24 h. High performance and low-cost SnS photocathode represent a promising new material in the field of photoelectrochemical solar water splitting.

Cluster Analysis of Inhalant Allergens in South Korea: A Computational Model of Allergic Sensitization.

OBJECTIVES: Sensitization to specific inhalant allergens is a major risk factor for the development of atopic diseases, which impose a major socioeconomic burden and significantly diminish quality of life. However, patterns of inhalant allergic sensitization have yet to be precisely described. Therefore, to enhance the understanding of aeroallergens, we performed a cluster analysis of inhalant allergic sensitization using a computational model. METHODS: Skin prick data were collected from 7,504 individuals. A positive skin prick response was defined as an allergen-to-histamine wheal ratio ≥1. To identify the clustering of inhalant allergic sensitization, we performed computational analysis using the four-parameter unified-Richards model. RESULTS: Hierarchical cluster analysis grouped inhalant allergens into three clusters based on the Davies-Bouldin index (0.528): cluster 1 (Dermatophagoides pteronyssinus and Dermatophagoides farinae), cluster 2 (mugwort, cockroach, oak, birch, cat, and dog), and cluster 3 (Alternaria tenus, ragweed, Candida albicans, Kentucky grass, and meadow grass). Computational modeling revealed that each allergen cluster had a different trajectory over the lifespan. Cluster 1 showed a high level (>50%) of sensitization at an early age (before 19 years), followed by a sharp decrease in sensitization. Cluster 2 showed a moderate level (10%-20%) of sensitization before 29 years of age, followed by a steady decrease in sensitization. However, cluster 3 revealed a low level (<10%) of sensitization at all ages. CONCLUSION: Computational modeling suggests that allergic sensitization consists of three clusters with distinct patterns at different ages. The results of this study will be helpful to allergists in managing patients with atopic diseases.

The epidemiology of appendicitis and appendectomy in South Korea: national registry data.

BACKGROUND: Appendicitis is one of the most frequent acute surgical conditions of the abdomen, and appendectomy is one of the most commonly performed operations in the world. However, epidemiological data on appendicitis have not been reported for South Korean or East Asian populations. METHODS: We analyzed the epidemiological features and lifetime risk of appendicitis and appendectomy in South Korea using data collected for the national health insurance database from 2005 through 2007. RESULTS: Appendectomy was performed in 59.70% of inpatients diagnosed with appendicitis. The overall incidences of appendicitis, total appendectomy, and perforated appendectomy were 22.71, 13.56, and 2.91 per 10 000 population per year, respectively. The incidence of appendicitis and appendectomy showed clear seasonality, with a peak in summer. The standardized lifetime risks of appendicitis and appendectomy were constant from 2005 through 2007. A life table model suggests that the lifetime risk of appendicitis is 16.33% for males and 16.34% for females, and that the lifetime risk of appendectomy is 9.89% for males and 9.61% for females. CONCLUSIONS: As compared to results obtained in research on Western populations, appendicitis and appendectomy had a similar perforation rate and seasonality, but a higher overall incidence, in South Koreans. Between 2005 and 2007, the incidence of appendicitis and appendectomy was constant. Overall, an estimated 15 incidental appendectomies are performed to prevent 1 inpatient with suspected appendicitis, and 26 incidental appendectomies are performed to prevent 1 appendectomy. Incidental appendectomy may have greater preventive value in Koreans.

Difference of fetal heart rate accelerations based on 10 and 15 beats per minute.

AIM: To evaluate the correlation of 10 b.p.m.-10 s and 15 b.p.m.-15 s fetal heart rate (FHR) accelerations in gestations before or after 32 weeks using computerized analysis. METHODS: A combination of amplitude and duration of FHR accelerations, 10 b.p.m.-10 s (Acc10-10) and 15 b.p.m.-15 s (Acc15-15), was analyzed according to gestational weeks between January 1999 and December 2005 in 2358 normal pregnant women who received a non-stress test at 30-42 gestational weeks. A linear regression model between Acc10-10 and Acc15-15 was estimated, and the duration difference between 10 b.p.m. and 15 b.p.m. was converted into seconds. RESULTS: Before 32 weeks of gestation, the mean number of FHR accelerations based on 15 b.p.m. was below 2.00 (mean + or - standard error, 1.58 + or - 0.19). The correlation between Acc10-10 and Acc15-15 was Acc15-15 + 2.8 = Acc10-10 (r(2) = 0.94, P = 0.0013). The mean duration difference between 10 b.p.m. and 15 b.p.m. was 36.8 s (range, 4-227 s). CONCLUSIONS: Our study verified the difference of Acc10-10 and Acc15-15 using computerized analysis as the base of visual interpretation of the definition of FHR acceleration. Acc15-15 did not occur often enough to be relevant to the definition of FHR acceleration before 32 weeks' gestation. The difference between the mean number of FHR accelerations based on 10 b.p.m. and 15 b.p.m. within a 20-min window was 2.8.

Conventional linear criteria with sample entropy in the interpretation of reactive antepartum fetal heart rate tracings.

OBJECTIVE: To compare the test duration times and rate of nonreactive results between the conventional linear reactive criteria (CLRC) and the modified nonlinear reactive criteria (MNRC) in electronic fetal heart rate (FHR) monitoring. The MNRC are the CLRC with the addition of approximate entropy or sample entropy. METHODS: One thousand women with singleton pregnancies between 30 and 37 weeks' gestation were selected. They visited Hanyang University Hospital for non-stress tests (NSTs). In these patients, FHR tracings were recorded for 50 min including the first and second 20 min of NST and 10 min of vibroacoustic stimulation test. All patients had a reactive NST with CLRC in these antepartum FHR tests. The rate of nonreactive tests and test duration times of these linear and nonlinear criteria were calculated and compared. RESULTS: The rate of nonreactive tests within a 20- and 40-min period with the MNRC (6.8 and 1.2%) was significantly lower than with the CLRC (35.2 and 10.5%, respectively; p < 0.001). To meet the reactive criteria, the mean durations of the MNRC and the CLRC were 11.47 (95% CI, 11.11-11.84) and 18.45 (95% CI, 17.79-19.12) min, respectively (p < 0.001). The MNRC led to a significant reduction in testing time of 37.8% compared to the CLRC. The rate of reactive tests using only sample entropy (0.20), calculated over 5-min segments of FHR tracings, was 88.3% (95% CI, 88.0-88.7). It was close to the results using the MNRC (93.2%) in the 20-min time window. CONCLUSION: The use of the MNRC significantly reduced the test duration times and decreased the rate of nonreactive tests when compared to the CLRC. It may be useful in providing more rapid and accurate assessment of the fetus in electronic FHR monitoring.