Modeling of an Interconnected Fluidized Bed Reactor for Chemical Looping Combustion

Chemical Looping Combustion (CLC) is comprised of two reactors, in which direct contact between air and fuel is avoided. A metal oxide, as oxygen carrier, transports oxygen from the air reactor to the fuel reactor while circulating between them. Based on the hydrodynamics coupled with reaction kinetics of oxygen carrier from the literature, a model for an interconnected fluidized bed reactor has been developed to optimize the design and operation of the reactor system. The model considers the chemical reaction of a single particle and a particle population balance for the calculation of bed particle conversion. The core-annulus and two-phase hydrodynamic models are assumed for the air and fuel reactors, respectively. Predictions of the oxygen emission, particle conversion and fuel conversion efficiency under different operating conditions are presented for a pilot scale CLC reactor system

A 9-year-old Korean girl with Fontaine progeroid syndrome: a case report with further phenotypical delineation and description of clinical course during long-term follow-up

Background Gorlin–Chaudhry–Moss syndrome (GCMS) and Fontaine–Farriaux syndrome (FFS) are extremely rare genetic disorders that share similar clinical manifestations. Because a de novo missense mutation of the solute carrier family 25 member 24 (SLC25A24) gene was suggested to be the common genetic basis of both syndromes, it has been proposed recently that they be integrated into a single disorder under the name of Fontaine progeroid syndrome (FPS). Case presentation A 9-year-old Korean girl presented with typical clinical features of FPS. She had generalized loose skin with decreased subcutaneous fat, skin wrinkling on the forehead and limbs, skull deformities and a peculiar facial appearance with microphthalmia and midface hypoplasia, anomalies of the digits and nails, a large umbilical hernia and a nearly normal developmental outcome. She exhibited prenatal and postnatal growth retardation together with short stature, and records showed that her height and weight were invariably under − 2.0 SD from birth to the age of 10 years. SLC25A24 analysis revealed a heterozygous mutation reported previously, NM_013386:c.650G > A, p.[Arg217His]. After screening her family for the identified mutation, she was confirmed as being a de novo case of FPS caused by an SLC25A24 mutation. Conclusion We describe a Korean girl with typical clinical findings of FPS and a de novo mutation in SLC25A24, as well as 10 years of clinical follow-up, including growth and developmental achievements.This study was supported by grant no. 05–2018-0010 from the SNUH Research Fund. The funder had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript

Plasmonic Terahertz Wave Detector Based on Silicon Field-Effect Transistors with Asymmetric Source and Drain Structures

In this paper, we present the validity and potential capacity of a modeling and simulation environment for the nonresonant plasmonic terahertz (THz) detector based on the silicon (Si) field-effect transistor (FET) with a technology computer-aided design (TCAD) platform. The nonresonant and "overdamped" plasma-wave behaviors have been modeled by introducing a quasi-plasma electron charge box as a two-dimensional electron gas (2DEG) in the channel region only around the source side of Si FETs. Based on the coupled nonresonant plasma-wave physics and continuity equation on the TCAD platform, the alternate-current (AC) signal as an incoming THz wave radiation successfully induced a direct-current (DC) drain-to-source output voltage as a detection signal in a sub-THz frequency regime under the asymmetric boundary conditions with a external capacitance between the gate and drain. The average propagation length and density of a quasi-plasma have been confirmed as around 100 nm and 1x10(19)/cm(3), respectively, through the transient simulation of Si FETs with the modulated 2DEG at 0.7 THz. We investigated the incoming radiation frequency dependencies on the characteristics of the plasmonic THz detector operating in sub-THz nonresonant regime by using the quasi-plasma modeling on TCAD platform. The simulated dependences of the photoresponse with quasi-plasma 2DEG modeling on the structural parameters such as gate length and dielectric thickness confirmed the operation principle of the nonresonant plasmonic THz detector in the Si PET structure. The proposed methodologies provide the physical design platform for developing novel plasmonic THz detectors operating in the nonresonant detection mode.open3

A Study to Verify the Practicality of Introducing an Arson Dog (K-9) Unit in Field Investigations

Combustion improvers are often found in acts of arson. Until recently, in fire investigations in Korea, these substances have been identified only by the olfactory sense of the fire inspectors or conventional gas detectors. These methods are neither efficient nor feasible in damaged buildings or large areas. Research on the canine sense of smell has shown that a dog can distinguish the remains of combusted hydrocarbon compounds, even in a large, open area. Field tests confirmed that arson dogs can find combustion improvers at fire sites in about five to 77 s. Therefore, this study verified the practicality of introducing arson dog units in field investigations of fire sites to identify combustion improvers sprayed for committing arson

Expression and functional role of formyl peptide receptor in human bone marrow-derived mesenchymal stem cells

AbstractWe investigated the expression of formyl peptide receptor (FPR) and its functional role in human bone marrow-derived mesenchymal stem cells (MSCs). We analyzed the expression of FPR by using ligand-binding assay with radio-labeled N-formyl-met-leu-phe (fMLF), and found that MSCs express FPR. FMLF stimulated intracellular calcium increase, mitogen-activated protein kinases activation, and Akt activation, which were mediated by Gi proteins. MSCs were chemotactically migrated to fMLF. FMLF-induced MSC chemotaxis was also completely inhibited by pertussis toxin, LY294002, and PD98059, indicating the role of Gi proteins, phosphoinositide 3-kinase, and extracellular signal regulated protein kinase. N-terminal fragment of annexin-1, Anx-1(2–26), an endogenous agonist for FPR, also induced chemotactic migration of MSCs. Thus MSCs express functional FPR, suggesting a new (patho)physiological role of FPR and its ligands in regulating MSC trafficking during induction of injured tissue repair

Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant

We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology supernova remnant shows a clumpy distribution, and the line intensity is nearly constant with radius. The C III 977 line, though too weak to be mapped over the whole remnant, is shown to vary radially. The line intensity peaks at about half the radius, and drops at the edge of the remnant. Both the clumpy distribution of C IV and the rise in the C IV to C III ratio towards the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.Comment: 9 pages, 4 figures, will be published in ApJ December 1, 2007, v670n2 issue. see http://astro.snu.ac.kr/~jhshinn/ms.pd

Pre and postoperative lactate levels and lactate clearance in predicting in-hospital mortality after surgery for gastrointestinal perforation

Abstract Background This study aimed to compare the prognostic significance of pre and postoperative lactate levels and postoperative lactate clearance in the prediction of in-hospital mortality after surgery for gastrointestinal (GI) perforation. Methods Among patients who underwent surgery for GI perforation between 2013 and 2017, only patients whose lactate were measured before and after surgery were included and divided into an in-hospital mortality group and a survival group. Data on demographics, comorbidities, pre and postoperative laboratory test results, and operative findings were collected. Risk factors for in-hospital mortality were identified, and receiver-operating characteristic (ROC) curve analysis was performed for pre and postoperative lactate levels and postoperative lactate clearance. Results Of 104 included patients, 17 patients (16.3%) died before discharge. The in-hospital mortality group demonstrated higher preoperative lactate (6.3 ± 5.1 vs. 3.5 ± 3.2, P = 0.013), SOFA score (4.5 ± 1.7 vs. 3.4 ± 2.3, P = 0.004), proportions of patients with lymphoma (23.5% vs. 2.3%, P = 0.006), and rates of contaminated ascites (94.1% vs. 68.2%, P = 0.036) and lower preoperative hemoglobin (10.4 ± 1.6 vs. 11.8 ± 2.4, P = 0.018) compare to the survival group. Multivariate analysis revealed that postoperative lactate (HR 1.259, 95% CI 1.084–1.463, P = 0.003) and preoperative hemoglobin (HR 0.707, 95% CI 0.520–0.959, P = 0.026) affected in-hospital mortality. In the ROC curve analysis, the largest area under the curve (AUC) was shown in the postoperative lactate level (AUC = 0.771, 95% CI 0.678–0.848). Conclusion Of perioperative lactate levels in patients underwent surgery for GI perforation, postoperative lactate was the strongest predictor for in-hospital mortality

Inflammatory Myofibroblastic Tumor of the Kidney Misdiagnosed as Renal Cell Carcinoma

The inflammatory myofibroblastic tumor (IMT), also knowns as inflammatory pseuduotumor, is a soft tissue lesion of unknown etiology. In the urogenital tract, IMT mainly affects the urinary bladder or prostate, but rarely the kidney. It has been considered as a nonneoplastic reactive inflammatory lesion, but nowadays, it is regarded as a neoplasm due to its high recurrence rate and metastasis. We describe a case of a 61-yr-old woman that had originally been misdiagnosed as renal cell carcinoma, which was pathologically revealed to be an IMT

Plasma cell granuloma in cyclosporine-induced gingival overgrowth: a report of two cases with immunohistochemical positivity of interleukin-6 and phospholipase C-gamma1.

We report two cases of gingival plasma cell granuloma in a 34-yr-old and 40-yr-old two male renal transplant recipients with cyclosporine A (CsA)-induced gingival overgrowth (GO). Histologically, these lesions were composed of mature plasma cells, showing polyclonality for both lambda and kappa light chains and fibrovascular connective tissue stroma. In addition to the fact that CsA-induced plasma cell granuloma is rare, the salient features of our cases were the secretion of interleukin-6 and overexpression of phospholipase C- gamma 1 of the tumor cells, which may explain the mechanisms of CsA- induced GO

Elevated glucocorticoid alters the developmental dynamics of hypothalamic neurogenesis in zebrafish

Exposure to excess glucocorticoid (GC) during early development is implicated in adult dysfunctions. Reduced adult hippocampal neurogenesis is a well-known consequence of exposure to early life stress or elevated GC, however the effects on neurogenesis during development and effects on other brain regions are not well understood. Using an optogenetic zebrafish model, here we analyse the effects of GC exposure on neurogenesis during development in the whole brain. We identify that the hypothalamus is a highly GC-sensitive region where elevated GC causes precocious development. This is followed by failed maturation and early decline accompanied by impaired feeding, growth, and survival. In GC-exposed animals, the developmental trajectory of hypothalamic progenitor cells is strikingly altered, potentially mediated by direct regulation of transcription factors such as rx3 by GC. Our data provide cellular and molecular level insight into GC-induced alteration of the hypothalamic developmental trajectory, a process crucial for health across the life-course