The Globular Cluster System of the Coma cD Galaxy NGC 4874 from Hubble Space Telescope ACS and WFC3/IR Imaging

We present new HST optical and near-infrared (NIR) photometry of the rich globular cluster (GC) system of NGC 4874, the cD galaxy in the core of the Coma cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for Surveys in the F475W (g) and F814W (I) passbands and the Wide Field Camera 3 IR Channel in F160W (H). The GCs in this field exhibit a bimodal optical color distribution with more than half of the GCs falling on the red side at g-I > 1. Bimodality is also present, though less conspicuously, in the optical-NIR I-H color. Consistent with past work, we find evidence for nonlinearity in the g-I versus I-H color-color relation. Our results thus underscore the need for understanding the detailed form of the color-metallicity relations in interpreting observational data on GC bimodality. We also find a very strong color-magnitude trend, or "blue tilt," for the blue component of the optical color distribution of the NGC 4874 GC system. A similarly strong trend is present for the overall mean I-H color as a function of magnitude; for M_814 < -10 mag, these trends imply a steep mass-metallicity scaling with $Z\propto M_{\rm GC}^{1.4\pm0.4}$, but the scaling is not a simple power law and becomes much weaker at lower masses. As in other similar systems, the spatial distribution of the blue GCs is more extended than that of the red GCs, partly because of blue GCs associated with surrounding cluster galaxies. In addition, the center of the GC system is displaced by 4+/-1 kpc towards the southwest from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally, we remark on a dwarf elliptical galaxy with a noticeably asymmetrical GC distribution. Interestingly, this dwarf has a velocity of nearly -3000 km/s with respect to NGC 4874; we suggest it is on its first infall into the cluster core and is undergoing stripping of its GC system by the cluster potential.Comment: 24 pages, 20 figures, accepted for publication in Ap

Spontaneous Intraperitoneal Bladder Perforation Associated with Urothelial Carcinoma with Divergent Histologic Differentiation, Diagnosed by CT Cystography

Spontaneous bladder perforation is a very rare event. Prompt diagnosis of this injury is very important, particularly with intraperitoneal perforation, because mortality increases if surgical repair is delayed. Previous studies have reported that plain cystography is the primary modality of imaging study rather than relatively insensitive computed tomography (CT) when bladder perforation is suspected. We report here a rare case of spontaneous intraperitoneal perforation of the bladder associated with urothelial carcinoma with divergent histologic differentiation, as diagnosed with CT cystography

Analysis and Design of Three-Phase Buck Rectifier Employing UPS to Supply High Reliable DC Power

In the DC distribution system, to step down the DC voltage level from the AC grid voltage, the conventional topologies require multiple power conversion stages and bulky line-frequency transformers, which degrade their power density and cost-effectiveness. In addition, the conventional topologies suffer from a shoot-through problem resulting in their low system reliability. In this paper, to overcome the above issues, systematic design approaches of a three-phase buck rectifier with an uninterruptible power supply (UPS) and a protection algorithm are proposed to obtain the high reliability of the DC distribution system, which can deal with fault conditions and can regulate the output voltage level. It only requires a single stage of the three-phase buck rectifier. Also, a thyristor switch is added without any commutation circuits to cut off the output from the fault circuit. The shoot-through faults do not occur in the buck rectifier, leading to high reliability. A dual-active-bridge (DAB) DC-DC converter is applied as the UPS to supply the electric power from the battery when the buck rectifier is shut down under the fault conditions. Finally, the protection algorithm is proposed to detect the fault conditions and to regulate the output voltage level

A new technique for superselective catheterization of arteries: preshaping of a micro-guide wire into a shepherd's hook form

OBJECTIVE: We wanted to introduce a new technique for superselective catheterization of arteries with preshaping of a micro-guide wire into a shepherd's hook form, and this is useful for superselection of small arteries branching at an acute angle from a large parent artery for the treatment of tumors and hemorrhages. MATERIALS AND METHODS: We developed a superselective catheterization technique by using preshaping of a micro-guide wire into a shepherd's hook form. We encountered six patients in our practice for whom we failed to catheterize the small tumor-feeding arteries that branched at an acute angle from wide parent arteries during chemoembolization of hepatocellular carcinoma; the parent arteries were the right inferior phrenic artery (n = 4) and the left gastric artery (n = 1) from the celiac axis with celiac stenosis due to compression by the median arcuate ligament and the proper hepatic artery from the gastroduodenal artery (n = 1) in a patient who had celiac axis occlusion with collateral circulation via the pancreaticoduodenal arcade from the superior mesenteric artery. In these consecutive six patients, we tested the usefulness of this new technique with employing preshaping of a micro-guide wire into a shepherd's hook form for superselective catheterization of targeted vessels. RESULTS: The target arteries were successfully catheterized and satisfactory transcatheter arterial chemoembolization was performed in all six patients. There were no significant complications such as arterial dissection. CONCLUSION: We developed a technique that is effective for superselection of vessels with preshaping of micro-guide wire into a shepherd's hook form, and we successfully applied it during chemoembolization of hepatocellular carcinoma. This technique can be useful for superselection of small arteries that branch from a large parent artery at acute angles for the treatment of tumors and hemorrhages

A new technique for superselective catheterization of arteries: preshaping of a micro-guide wire into a shepherd's hook form

OBJECTIVE: We wanted to introduce a new technique for superselective catheterization of arteries with preshaping of a micro-guide wire into a shepherd's hook form, and this is useful for superselection of small arteries branching at an acute angle from a large parent artery for the treatment of tumors and hemorrhages. MATERIALS AND METHODS: We developed a superselective catheterization technique by using preshaping of a micro-guide wire into a shepherd's hook form. We encountered six patients in our practice for whom we failed to catheterize the small tumor-feeding arteries that branched at an acute angle from wide parent arteries during chemoembolization of hepatocellular carcinoma; the parent arteries were the right inferior phrenic artery (n = 4) and the left gastric artery (n = 1) from the celiac axis with celiac stenosis due to compression by the median arcuate ligament and the proper hepatic artery from the gastroduodenal artery (n = 1) in a patient who had celiac axis occlusion with collateral circulation via the pancreaticoduodenal arcade from the superior mesenteric artery. In these consecutive six patients, we tested the usefulness of this new technique with employing preshaping of a micro-guide wire into a shepherd's hook form for superselective catheterization of targeted vessels. RESULTS: The target arteries were successfully catheterized and satisfactory transcatheter arterial chemoembolization was performed in all six patients. There were no significant complications such as arterial dissection. CONCLUSION: We developed a technique that is effective for superselection of vessels with preshaping of micro-guide wire into a shepherd's hook form, and we successfully applied it during chemoembolization of hepatocellular carcinoma. This technique can be useful for superselection of small arteries that branch from a large parent artery at acute angles for the treatment of tumors and hemorrhages

Association between physical activity and episodic memory and the moderating effects of the apolipoprotein E ε4 allele and age

BackgroundAn abundance of evidence indicates that physical activity may protect against Alzheimer’s disease (AD) and related cognitive decline. However, little is known about the association between physical activity and AD-related cognitive decline according to age and the apolipoprotein E (APOE) ε4 allele (APOE4) as major risk factors. Therefore, we examined whether age and APOE4 status modulate the effects of physical activity on episodic memory as AD-related cognition in non-demented older adults.MethodsWe enrolled 196 adults aged between 65 and 90 years, with no dementia. All participants underwent comprehensive clinical assessments including physical activity evaluation and APOE genotyping. The AD-related cognitive domain was assessed by the episodic memory, as the earliest cognitive change in AD, and non-memory cognition for comparative purposes. Overall cognition was assessed by the total score (TS) of the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological battery.ResultsWe found significant physical activity × age and physical activity × APOE4 interaction effects on episodic memory. Subgroup analyses indicated that an association between physical activity and increased episodic memory was apparent only in subjects aged &gt; 70 years, and in APOE4-positive subjects.ConclusionOur findings suggest that physical activity has beneficial effects on episodic memory, as an AD-related cognitive domain, in individuals aged &gt; 70 years and in APOE4-positive individuals. Physicians should take age and APOE4 status account into when recommending physical activity to prevent AD-related cognitive decline

iPSC Modeling of Presenilin1 Mutation in Alzheimer's Disease with Cerebellar Ataxia.

Disease modeling of Alzheimer's disease (AD) has been hampered by the lack of suitable cellular models while animal models are mainly based on the overexpression of AD-related genes which often results in an overemphasis of certain pathways and is also confounded by aging. In this study, we therefore developed and used induced pluripotent stem cell (iPSC) lines from a middle-aged AD patient with a known presenilin 1 (PSEN1) mutation (Glu120Lys; PS1-E120K) and as a control, an elderly normal subject. Using this approach, we demonstrated that the extracellular accumulation of Aβ was dramatically increased in PS1-E120K iPSC-derived neurons compared with the control iPSC line. PS1-E120K iPSC-derived neurons also exhibited high levels of phosphorylated tau, as well as mitochondrial abnormalities and defective autophagy. Given that the effect of aging is lost with iPSC generation, these abnormal cellular features are therefore indicative of PSEN1-associated AD pathogenesis rather than primary changes associated with aging. Taken together, this iPSC-based approach of AD modeling can now be used to better understand AD pathogenesis as well as a tool for drug discovery.This work was supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI14C2746) and a grant (2016-0588) from the Asan Institute for Life Sciences