Chiral symmetry and taste symmetry from the eigenvalue spectrum of staggered Dirac operators

We investigate general properties of the eigenvalue spectrum for improved staggered quarks. We introduce a new chirality operator $[\gamma_5 \otimes 1]$ and a new shift operator $[1 \otimes \xi_5]$, which respect the same recursion relation as the $\gamma_5$ operator in the continuum. Then we show that matrix elements of the chirality operator sandwiched between two eigenstates of the staggered Dirac operator are related to those of the shift operator by the Ward identity of the conserved $U(1)_A$ symmetry of staggered fermion actions. We perform a numerical study in quenched QCD using HYP staggered quarks to demonstrate the Ward identity. We introduce a new concept of leakage patterns which collectively represent the matrix elements of the chirality operator and the shift operator sandwiched between two eigenstates of the staggered Dirac operator. The leakage pattern provides a new method to identify zero modes and non-zero modes in the Dirac eigenvalue spectrum. This method is as robust as the spectral flow method but requires much less computing power. Analysis using a machine learning technique confirms that the leakage pattern is universal, since the staggered Dirac eigenmodes on normal gauge configurations respect it. In addition, the leakage pattern can be used to determine a ratio of renormalization factors as a by-product. We conclude that it might be possible and realistic to measure the topological charge $Q$ using the Atiya-Singer index theorem and the leakage pattern of the chirality operator in the staggered fermion formalism.Comment: 27 pages, 78 figures, 10 tables, references updated, more explanation adde

Clinical outcome of acute necrotizing encephalopathy in related to involving the brain stem of single institution in Korea

PurposeAcute necrotizing encephalopathy (ANE) is a fulminant disease of the brain characterized by bilateral thalamic lesions, and is prevalent among children in East Asia. The prognosis of ANE is usually poor with a high mortality rate and neurological sequelae. This study aimed to delineate the clinical characteristics and prognostic factors of ANE.MethodsWe retrospectively analyzed clinical data of 399 pediatric patients with encephalitis who were admitted to Samsung Medical Center from December 1998 to March 2011. We enrolled ten patients (11 cases) with ANE and analyzed their demographic, clinical, and neuroimaging data. The location and extent of the brain regions were checked based on fluid-attenuated inversion recovery, T1-, and T2-weighted imaging findings; the presence of contrast enhancement, restricted diffusion, and hemorrhage.ResultsTen patients were identified, including one patient with two episodes. The median age of onset was 1.5 years (0.4-8.4 years). The mortality rate was 40%, and only 30% of patients survived without neurological sequelae. The definite involvement of the brainstem on brain magnetic resonance imaging was significantly correlated with mortality (P=0.04).ConclusionBroad and extensive brainstem involvement suggested the fulminant course of ANE. Early diagnosis of ANE before brainstem involvement, through careful identification of symptoms of brain dysfunction, may be the best way to achieve better neurological outcomes

Roles of endothelial A-type lamins in migration of T cells on and under endothelial layers

Stiff nuclei in cell-dense microenvironments may serve as distinct biomechanical cues for cell migration, but such a possibility has not been tested experimentally. As a first step addressing this question, we altered nuclear stiffness of endothelial cells (ECs) by reducing the expression of A-type lamins using siRNA, and investigated the migration of T cells on and under EC layers. While most T cells crawling on control EC layers avoided crossing over EC nuclei, a significantly higher fraction of T cells on EC layers with reduced expression of A-type lamins crossed over EC nuclei. This result suggests that stiff EC nuclei underlying T cells may serve as "duro-repulsive" cues to direct T cell migration toward less stiff EC cytoplasm. During subendothelial migration under EC layers with reduced expression of A-type lamins, T cells made prolonged contact and substantially deformed EC nuclei, resulting in reduced speed and directional persistence. This result suggests that EC nuclear stiffness promotes fast and directionally persistent subendothelial migration of T cells by allowing minimum interaction between T cells and EC nuclei.open11102sciescopu

Nusinersen demonstrates effectiveness in treating spinal muscular atrophy: findings from a three-year nationwide study in Korea

IntroductionNusinersen is the first drug approved for spinal muscular atrophy (SMA) treatment. In this study, we aimed to evaluate the long-term safety and efficacy of nusinersen, assess the therapeutic effects based on the treatment initiation timing and baseline motor function, and explore the perception of functional improvement from either parents or patients, utilizing 3-year nationwide follow-up data in South Korea.MethodsWe enrolled patients with SMA who were treated with nusinersen under the National Health Insurance coverage, with complete motor score records available and a minimum treatment duration of 6 months. To evaluate the motor function of patients, the Hammersmith Infant Neurological Examination-2 (HINE-2) was used for type 1 and the Expanded Hammersmith Functional Motor Scale (HFMSE) was used for types 2 and 3 patients. A significant improvement was defined as a HINE-2 score gain ≥5 for patients with type 1 and an HFMSE score ≥ 3 for patients with types 2 and 3 SMA. Effects of treatment timing were assessed. Patients with type 2 were further categorized based on baseline motor scores for outcome analysis. We also analyzed a second dataset from five tertiary hospitals with the information on parents/patients-reported impressions of improvement.ResultsThe study comprised 137 patients, with 21, 103, and 13 patients representing type 1, 2, and 3 SMA, respectively. At the 3-year follow-up, the analysis encompassed 7 patients with type 1, 12 patients with type 2, and none with type 3. Nearly half of all enrolled patients across SMA types (42.8, 59.2 and 46.2%, respectively) reached the 2-year follow-up for analysis. Patients with type 1 SMA exhibited gradual motor function improvement over 1-, 2-, and 3-year follow-ups (16, 9, and 7 patients, respectively). Patients with type 2 SMA demonstrated improvement over 1-, 2-, and 3-year follow-ups (96, 61 and 12 patients, respectively). Early treatment from symptom onset resulted in better outcomes for patients with type 1 and 2 SMA. In the second dataset, 90.7% of 108 patients reported subjective improvement at the 1-year follow-up.ConclusionNusinersen treatment for types 1–3 SMA is safe and effective in long-term follow-up. Early treatment initiation was a significant factor affecting long-term motor outcome

Improved Outcome of Central Nervous System Germ Cell Tumors: Implications for the Role of Risk-adapted Intensive Chemotherapy

To determine the impact of treatment protocols on the outcome of central nervous system germ cell tumors (CNS-GCTs), we reviewed the medical records of 53 patients who received front-line chemotherapy from September 1997 to September 2006. Pure germinoma, normal alpha-fetoprotein level and beta-human chorionic gonadotropin level <50 mIU/mL were regarded as low-risk features and the others as high-risk. Patients from different time periods were divided into 3 groups according to the chemotherapy protocols. Group 1 (n=19) received 4 cycles of chemotherapy comprising cisplatin, etoposide and bleomycin. Group 2 (n=16) and group 3 (n=18) received 4 cycles of chemotherapy with cisplatin, etoposide, cyclophosphamide and vincristine in the former and with carboplatin, etoposide, cyclophosphamide and bleomycin in the latter. In group 2 and group 3, high-risk patients received double doses of cisplatin, carboplatin and cyclophosphamide. Radiotherapy was given after chemotherapy according to the clinical requirements. The event-free survivals of groups 1, 2, and 3 were 67.0%, 93.8%, and 100%, respectively (group 1 vs. 2, P=0.06; group 2 vs. 3, P=0.29; group 1 vs. 3, P=0.02). Our data suggest that risk-adapted intensive chemotherapy may improve the outcome of patients with malignant CNS-GCTs

Managing Intergenerational Family Obligations in a Transnational Migration Context : Korean Professional and Educational Migrant Families in Singapore

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Soil Moisture Content Estimation Based on Sentinel-1 SAR Imagery Using an Artificial Neural Network and Hydrological Components

This study estimates soil moisture content (SMC) using Sentinel-1A/B C-band synthetic aperture radar (SAR) images and an artificial neural network (ANN) over a 40 &times; 50-km2 area located in the Geum River basin in South Korea. The hydrological components characterized by the antecedent precipitation index (API) and dry days were used as input data as well as SAR (cross-polarization (VH) and copolarization (VV) backscattering coefficients and local incidence angle), topographic (elevation and slope), and soil (percentage of clay and sand)-related data in the ANN simulations. A simple logarithmic transformation was useful in establishing the linear relationship between the observed SMC and the API. In the dry period without rainfall, API did not decrease below 0, thus the Dry days were applied to express the decreasing SMC. The optimal ANN architecture was constructed in terms of the number of hidden layers, hidden neurons, and activation function. The comparison of the estimated SMC with the observed SMC showed that the Pearson&rsquo;s correlation coefficient (R) and the root mean square error (RMSE) were 0.85 and 4.59%, respectively

PRRT2‐positive self‐limited infantile epilepsy: Initial seizure characteristics and response to sodium channel blockers

Abstract Objective Self‐limited infantile epilepsy (SeLIE) has distinctive clinical features, and the PRRT2 gene is known to be a considerable genetic cause. There have been a few studies on PRRT2‐positive SeLIE only, and anti‐seizure medications are often required due to frequent seizures at initial seizure onset. This study aimed to provide clinical information for the early recognition of patients with PRRT2‐positive SeLIE and to propose effective anti‐seizure medications for seizure control. Methods We retrospectively reviewed 36 patients diagnosed with SeLIE with genetically confirmed pathogenic variants of PRRT2. In addition, six atypical cases with neonatal‐onset seizures and unremitting after 3 years of age were included to understand the expanded clinical spectrum of PRRT2‐related epilepsy. We analyzed the initial presentation, clinical course, and seizure control response to anti‐seizure medications. Results Patients with PRRT2‐related epilepsy had characteristic seizure semiology at the initial presentation, including all afebrile, clustered (n = 23, 63.9%), short‐duration (n = 33, 91.7%), and bilateral tonic–clonic seizures (n = 26, 72.2%). Genetic analysis revealed that c. 649dupC was the most common variant, and six patients had a 16p11.2 microdeletion containing the PRRT2 gene. One‐third of the patients were sporadic cases without a family history of epilepsy or paroxysmal movement disorders. In the 33 patients treated with anti‐seizure medications, sodium channel blockers, such as carbamazepine, were the most effective in seizure control. Significance Our results delineated the clinical characteristics of PRRT2‐positive SeLIE, differentiating it from other genetic infantile epilepsies and discovered the effective anti‐seizure medications for initial clustered seizure control. If afebrile bilateral tonic–clonic seizures develop in a normally developed infant as a clustered pattern, PRRT2‐positive SeLIE should be considered as a possible diagnosis, and sodium channel blockers should be administered as the first medication for seizure control