Synergistic amplification of beta-amyloid- and interferon-gamma-induced microglial neurotoxic response by the senile plaque component chromogranin A.

Twig, Gilad,Graf, Solomon A,Messerli, Mark A,Smith, Peter J S,Yoo, Seung H,Shirihai, Orian S American Physiological Society 2005 American journal of physiology. Cell physiology Vol.288 No.1

<P>Activation of the microglial neurotoxic response by components of the senile plaque plays a critical role in the pathophysiology of Alzheimer's disease (AD). Microglia induce neurodegeneration primarily by secreting nitric oxide (NO), tumor necrosis factor-alpha (TNFalpha), and hydrogen peroxide. Central to the activation of microglia is the membrane receptor CD40, which is the target of costimulators such as interferon-gamma (IFNgamma). Chromogranin A (CGA) is a recently identified endogenous component of the neurodegenerative plaques of AD and Parkinson's disease. CGA stimulates microglial secretion of NO and TNFalpha, resulting in both neuronal and microglial apoptosis. Using electrochemical recording from primary rat microglial cells in culture, we have shown in the present study that CGA alone induces a fast-initiating oxidative burst in microglia. We compared the potency of CGA with that of beta-amyloid (betaA) under identical conditions and found that CGA induces 5-7 times greater NO and TNFalpha secretion. Coapplication of CGA with betaA or with IFNgamma resulted in a synergistic effect on NO and TNFalpha secretion. CD40 expression was induced by CGA and was further increased when betaA or IFNgamma was added in combination. Tyrphostin A1 (TyrA1), which inhibits the CD40 cascade, exerted a dose-dependent inhibition of the CGA effect alone and in combination with IFNgamma and betaA. Furthermore, CGA-induced mitochondrial depolarization, which precedes microglial apoptosis, was fully blocked in the presence of TyrA1. Our results demonstrate the involvement of CGA with other components of the senile plaque and raise the possibility that a narrowly acting agent such as TyrA1 attenuates plaque formation.</P>

Comparative study on the heat transfer performance of micro-grooved anodized thermosyphon with R134a, R600a and R717 for low-temperature applications

A. L. Sriram Sudhan,A. Brusly Solomon,I. Darwin Immanuel 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11

A comparative heat transfer performance of an internally grooved anodized thermosyphon with eco-friendly refrigerants is presented in this study. Thermosiphons are fabricated with 50 numbers of axial micro-grooves having a width of 500 µm and a depth of 550 µm that is formed using an electrical discharge machining process. The micro-grooved surface was then anodized and characterized using SEM as well as DSA 25 drop shape analyzer. Later, the heat transfer performance of non-anodized grooved thermosyphon is studied by varying fill ratio (20-80 %), inclination angle (0-90°), and heat inputs (5-50 W). The heat transfer coefficient of the thermosyphon is improved by anodization by 20.9 %, 17.2 %, and 18.1 %, respectively, with R717, R134a, and R600a at optimum circumstances (30 % fill ratio and 60 o inclination angle). Due to the performance enhancement and zero global warming potential of R717, an anodized surface with the same is recommended for a wide range of heat transfer applications.

A development study of drain fluid gastrografin as a biomarker of anastomotic leak

David A. Clark,Edward Yeoh,Aleksandra Edmundson,Craig Harris,Andrew Stevenson,Daniel Steffens,Michael Solomon 대한대장항문학회 2022 Annals of Coloproctolgy Vol.38 No.2

Purpose: Anastomotic leakage (AL) is the anathema of colorectal surgery. Its occurrence leads to increased morbidity and mortality and a prolonged hospital stay. Much work has gone into studying various biomarkers in drain fluid to facilitate early detection of AL. This stage 2a development study aims to assess the safety and feasibility of reliably detecting the iodine in Gastrografin (GG; Bayer Australia Ltd.) in drain fluid and stool samples by dual-energy computed tomography (DECT). Methods: This is a prospective, observational, controlled, consecutive cohort study establishing the safety and feasibility of the detection of GG in surgical drain fluid and stool as a biomarker of AL when patients with a low pelvic colorectal anastomosis undergo luminal flushing of the rectal tube with GG. Results: Ten consecutive patients were allocated to the saline flush group and the following 10 to the GG flush group. Three patients in the saline flush group developed an AL. One patient in the GG flush group developed an AL. An elevation in the drain fluid GG was detected using DECT on the day of clinical deterioration. None of the patients in the control group were found to have a positive result on DECT. Conclusion: This study demonstrates the safety of a novel approach to the early detection of AL from extraperitoneal colorectal anastomoses. The technique requires validation in a larger cohort and a multicenter study is planned to investigate the efficacy of GG rectal tube flushes as an early biomarker of AL in low pelvic anastomoses.

Experimental analysis on performance assessment of a hybrid double cross flow tube arrangement in a shell and tube heat exchanger

D. P. Sam Solomon,V. Selladurai,A. S. Krishnan 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

The article presents the evolution of a novel configuration of tube placements in a shell and tube heat exchanger (HX). A CFD analysis on a double cross flow arrangement of tubes reveals improved mixing of the shell-fluid which is expected to increase heat transfer. This arrangement was modified for easier manufacture and maintenance, which led to the hybrid double cross flow (HDCF) arrangement. Experiments were carried out in the HDCFHX, for parallel and counter flows, to compare its performance against the conventional staggered arrangement. The HDCFHX comprises composite bundles of three and four tubes. The threetube bundle is arranged in a staggered manner to themselves and orthogonal to the four-tube bundle. Ambient air at of 32 °C was used as the shell-fluid for Reynolds number ranging from 500 to 1000, for a fixed flow rate of 0.6 kg/min of water entering the tubes at 85 °C. This arrangement was observed to enhance the heat transfer with relatively lesser increase in pressure drop. The HDCFHX gave a significant improvement in heat transfer rate per pressure drop of 17 % to 38 %, vis-à-vis the conventional staggered arrangement in the parallel mode. The counter flow mode overly exhibited a similar trend, wherein the increase in this ratio varied from 8.5 % to 27.5 %.

Modular Power Converter Integration based on Non-Conventional Power Switch Assembly and Interconnects

A. K. Solomon,A. Castellazzi,N. Delmonte,P. Cova 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This work presents the development of a highly integrated power switch, based on 70?m thin IGBTs and diodes rated at 600 V. The integration relies on advanced ceramic substrate technology, featuring double-etched patterned copper tracks for a fully bond-wire-less double-sided cooling packaging solution; viases are also used in the ceramic substrates for vertical current conduction, which enables the introduction of a ground-plane structure within the switch, with greatly reduced overall values of parasitic inductance. The paper also proposes an outline of system-level integration solutions for ensuring that low-inductance characteristics at switch level are not lost when interconnecting to input filter and load.

Geographical Variation in the Use of Diverting Loop Ileostomy in Australia and New Zealand Colorectal Surgeons

David A. Clark,Bree Stephensen,Aleksandra Edmundson,Daniel Steffens,Michael Solomon 대한대장항문학회 2021 Annals of Coloproctolgy Vol.37 No.5

Purpose: Anastomotic leak (AL) after a low pelvic anastomosis is a devastating complication, with short- and long-term morbidity and increased mortality. Surgeons may employ various adjuncts in an attempt to reduce AL rates or mitigate their impact. These include the use of temporary diverting ileostomy (TDI), transanal or rectal tubes and pelvic drains. This questionnaire evaluates the preferences and routine use of these adjuncts in Australasian colorectal surgeons.Methods: A cross-sectional survey was administered to Australian and New Zealand colorectal surgeons on September 20, 2018. The study survey consisted of 15 questions exploring basic demographics and the number of rectal resections and ileal pouches performed in 12 months, along with the surgeon’s preference for the use of diverting stomas, rectal tubes, and pelvic drains.Results: There were 90 respondents to the survey (31.6%). Surgeons in Western Australia (71.4%) were more likely to use a mandatory TDI in colorectal extraperitoneal anastomoses than surgeons in Queensland (14.3%). South Australian surgeons are more likely to employ a mandatory TDI (100%) for ileal pouches than Queensland surgeons (42.9%). Rectal tubes are not commonly utilized (40.0% never use them), and pelvic drains are (45.6% in all cases). Surgeons consider a median AL rate of 15% was felt to justify the use of a TDI in low pelvic anastomoses and a median AL rate of 10% for ileal pouchesConclusion: There is considerable geographical variation in colorectal surgical practice throughout Australia and New Zealand. While surgeons interrogate the same literature, there are presumably other factors that see translation into variations in clinical practice.

Performance-based wind design of tall buildings: concepts, frameworks, and opportunities

Matiyas A. Bezabeh,Girma T. Bitsuamlak,Solomon Tesfamariam 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.2

One of the next frontiers in structural wind engineering is the design of tall buildings using performance-based approaches. Currently, tall buildings are being designed using provisions in the building codes and standards to meet an acceptable level of public safety and serviceability. However, recent studies in wind and earthquake engineering have highlighted the conceptual and practical limitations of the code-oriented design methods. Performance-based wind design (PBWD) is the logical extension of the current wind design approaches to overcome these limitations. Towards the development of PBWD, in this paper, we systematically review the advances made in this field, highlight the research gaps, and provide a basis for future research. Initially, the anatomy of the Wind Loading Chain is presented, in which emphasis was given to the early works of Alan G. Davenport. Next, the current state of practice to design tall buildings for wind load is presented, and its limitations are highlighted. Following this, we critically review the state of development of PBWD. Our review on PBWD covers the existing design frameworks and studies conducted on the nonlinear response of structures under wind loads. Thereafter, to provide a basis for future research, the nonlinear response of simple yielding systems under long-duration turbulent wind loads is studied in two phases. The first phase investigates the issue of damage accumulation in conventional structural systems characterized by elastic-plastic, bilinear, pinching, degrading, and deteriorating hysteretic models. The second phase introduces methods to develop new performance objectives for PBWD based on joint peak and residual deformation demands. In this context, the utility of multi-variate demand modeling using copulas and kernel density estimation techniques is presented. This paper also presents joined fragility curves based on the results of incremental dynamic analysis. Subsequently, the efficiency of tuned mass dampers and self-centering systems in controlling the accumulation of damage in wind-excited structural systems are investigated. The role and the need for explicit modeling of uncertainties in PBWD are also discussed with a case study example. Lastly, two unified PBWD frameworks are proposed by adapting and revisiting the Wind Loading Chain. This paper concludes with a summary and a proposal for future research.

Invited Mini Review : Cohesin gene mutations in tumorigenesis: from discovery to clinical significance

( David A. Solomon ),( Jung Sik Kim ),( Todd Waldman ) 생화학분자생물학회(구 한국생화학분자생물학회) 2014 BMB Reports Vol.47 No.6

Cohesin is a multi-protein complex composed of four core subunits (SMC1A, SMC3, RAD21, and either STAG1 or STAG2) that is responsible for the cohesion of sister chromatids following DNA replication until its cleavage during mitosis thereby enabling faithful segregation of sister chromatids into two daughter cells. Recent cancer genomics analyses have discovered a high frequency of somatic mutations in the genes encoding the core cohesin subunits as well as cohesin regulatory factors (e.g. NIPBL, PDS5B, ESPL1) in a select subset of human tumors including glioblastoma, Ewing sarcoma, urothelial carcinoma, acute myeloid leukemia, and acute megakaryoblastic leukemia. Herein we review these studies including discussion of the functional significance of cohesin inactivation in tumorigenesis and potential therapeutic mechanisms to selectively target cancers harboring cohesin mutations. [BMB Reports 2014; 47(6): 299-310]

Structure and reactivity of a mononuclear non-haem iron(III)??peroxo complex

Cho, Jaeheung,Jeon, Sujin,Wilson, Samuel A.,Liu, Lei V.,Kang, Eun A.,Braymer, Joseph J.,Lim, Mi Hee,Hedman, Britt,Hodgson, Keith O.,Valentine, Joan Selverstone,Solomon, Edward I.,Nam, Wonwoo Nature Publishing Group, a division of Macmillan P 2011 Nature Vol.478 No.7370

Oxygen-containing mononuclear iron species??iron(iii)??peroxo, iron(iii)??hydroperoxo and iron(iv)??oxo??are key intermediates in the catalytic activation of dioxygen by iron-containing metalloenzymes. It has been difficult to generate synthetic analogues of these three active iron??oxygen species in identical host complexes, which is necessary to elucidate changes to the structure of the iron centre during catalysis and the factors that control their chemical reactivities with substrates. Here we report the high-resolution crystal structure of a mononuclear non-haem side-on iron(iii)??peroxo complex, [Fe(iii)(TMC)(OO)]<SUP>+</SUP>. We also report a series of chemical reactions in which this iron(iii)??peroxo complex is cleanly converted to the iron(iii)??hydroperoxo complex, [Fe(iii)(TMC)(OOH)]<SUP>2+</SUP>, via a short-lived intermediate on protonation. This iron(iii)??hydroperoxo complex then cleanly converts to the ferryl complex, [Fe(iv)(TMC)(O)]<SUP>2+</SUP>, via homolytic O??O bond cleavage of the iron(iii)??hydroperoxo species. All three of these iron species??the three most biologically relevant iron??oxygen intermediates??have been spectroscopically characterized; we note that they have been obtained using a simple macrocyclic ligand. We have performed relative reactivity studies on these three iron species which reveal that the iron(iii)??hydroperoxo complex is the most reactive of the three in the deformylation of aldehydes and that it has a similar reactivity to the iron(iv)??oxo complex in C??H bond activation of alkylaromatics. These reactivity results demonstrate that iron(iii)??hydroperoxo species are viable oxidants in both nucleophilic and electrophilic reactions by iron-containing enzymes.

A study on the estimation of the catch of large purse seine boat by combining AIS data and TAC catch data

Eun-A Song,Solomon Amoah Owiredu,Byeong-Yeob Kim,Kyoung-Hoon Lee,Sang-Lok Yoo,Kwang-Il Kim 한국수산해양기술학회(구 한국어업기술학회) 2023 한국수산해양기술학회 학술발표대회 Vol.2023 No.11