Publications by authors named "Seiichi Yamaguchi"

8 Publications

  • Page 1 of 1

Thermodynamic Analysis of Irreversible Desiccant Systems.

Entropy (Basel) 2018 Aug 9;20(8). Epub 2018 Aug 9.

Interdisciplinary Institute for Thermal Energy Conversion Engineering and Mathematics, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan.

A new general thermodynamic mapping of desiccant systems' performance is conducted to estimate the potentiality and determine the proper application field of the technology. This targets certain room conditions and given outdoor temperature and humidity prior to the selection of the specific desiccant material and technical details of the system configuration. This allows the choice of the operative state of the system to be independent from the limitations of the specific design and working fluid. An expression of the entropy balance suitable for describing the operability of a desiccant system at steady state is obtained by applying a control volume approach, defining sensible and latent effectiveness parameters, and assuming ideal gas behaviour of the air-vapour mixture. This formulation, together with mass and energy balances, is used to conduct a general screening of the system performance. The theoretical advantage and limitation of desiccant dehumidification air conditioning, maximum efficiency for given conditions constraints, least irreversible configuration for a given operative target, and characteristics of the system for a target efficiency can be obtained from this thermodynamic mapping. Once the thermo-physical properties and the thermodynamic equilibrium relationship of the liquid desiccant mixture or solid coating material are known, this method can be applied to a specific technical case to select the most appropriate working medium and guide the specific system design to achieve the target performance.
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http://dx.doi.org/10.3390/e20080595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7513120PMC
August 2018

Successful Endovascular Repair of Mycotic Aortic Pseudoaneurysm Followed by Aortoesophageal Fistula.

Ann Vasc Dis 2017 Jun;10(2):143-145

Department of Cardiovascular Surgery, Chiba Emergency Medical Center, Chiba, Japan.

Mycotic aneurysm of the aorta is a rare, but life-threatening pathology. In recent years, endovascular stent graft placement has been introduced as an effective alternative for treating infected aortic aneurysms. A 64-year-old woman with a history of paraplegia due to spinal cord injury was referred to our institute with fever and blood-tinged sputum. Computed tomography (CT) scan showed an 11-cm pseudoaneurysm arising from the proximal descending aorta, which was normal 1 month ago at the previous CT scan. The patient underwent thoracic endovascular aortic repair for the pseudoaneurysm, deployed with a transiliac access approach, and received antibacterial medical therapy. On postoperative day 11, she developed signs of infection, caused by an aortoesophageal fistula. The infection was treated conservatively with parenteral nutrition and antibiotic administration. The patient had an uneventful recovery and was discharged on postoperative day 113. At 2-year follow-up, she had a normal physical examination and CT angiography showed a marked reduction of the pseudoaneurysm sac. We report a successful endovascular stent grafting and subsequent medical treatment in a patient with a mycotic thoracic aortic pseudoaneurysm followed by a postoperative aortoesophageal fistula.
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http://dx.doi.org/10.3400/avd.cr.17-00005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579774PMC
June 2017

Esophageal necrosis after endovascular repair for ruptured aortic dissection.

Asian Cardiovasc Thorac Ann 2017 Nov 9;25(9):638-641. Epub 2016 Jun 9.

1 Department of Cardiovascular Surgery, Chiba Emergency Medical Center, Chiba, Japan.

A 78-year-old man presented with back pain and shock and was transferred to our hospital. Computed tomography showed a ruptured aortic dissection in which the false lumen was thrombosed with an ulcer-like projection, and the mid-esophagus was shifted to the right due to a mediastinal hematoma. He underwent emergency thoracic endovascular aortic repair of the descending thoracic aorta. One week later, esophageal necrosis occurred, and he died of mediastinitis and sepsis on postoperative day 16. Although esophageal necrosis is a rare and fatal complication after thoracic endovascular aortic repair, a management strategy has not yet been established.
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http://dx.doi.org/10.1177/0218492316654035DOI Listing
November 2017

Nonanastomotic rupture of thoracic aortic Dacron graft treated by endovascular stent graft placement.

Gen Thorac Cardiovasc Surg 2013 Jul 25;61(7):414-6. Epub 2012 Sep 25.

Department of Cardiovascular Surgery, Chiba Kaihin Municipal Hospital, 3-32-1 Isobe, Mihama-ku, Chiba-shi, 261-0012 Chiba, Japan.

A 61-year-old man had a Stanford type A acute aortic dissection, and the total aortic arch was replaced with 22-mm knitted Dacron graft in 1996. In 2006, he underwent mitral valve replacement and tricuspid valve repair due to severe mitral and tricuspid valve regurgitation. Although preoperative computed tomography (CT) scan suggested pseudoaneurysm around the Dacron graft replaced with aortic arch, it could not be repaired concomitantly. Four months later, in view of the technical difficulties of an open surgical procedure, the prosthetic graft failure was repaired by endovascular stent graft consisting of a Gianturco Z stent covered with an UBE woven Dacron graft. However, during a follow-up, aneurysm sac diameter increased without any sings of endoleak in follow-up CT scans. Redo endovascular stent graft placement using a Gore-TAG device was performed. Subsequently, shrinkage of the pseudoaneurysmal sac could be observed.
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http://dx.doi.org/10.1007/s11748-012-0158-4DOI Listing
July 2013

Myocarditis in a pediatric case of pandemic 2009H1N1 influenza.

Pediatr Int 2012 Aug;54(4):558-62

Departments of Pediatrics, Chiba Kaihin Municipal Hospital, Chiba, Japan.

We report a 6-year-old boy with no major disease history or allergic conditions initially presented with pneumonia, progressed to acute respiratory distress syndrome and acute myocarditis caused by pandemic 2009H1N1 influenza diagnosed with RT-PCR testing, successfully managed with mechanical ventilation and percutaneous cardiopulmonary support system. Marked transient elevation of IgE in acute phase of the disease and the subsequent diagnosis of atopic asthma in our patient suggested a possible role of an underlying allergic condition in the clinicopathological process. Critically ill 2009H1N1-infected patient with acute respiratory failure should carefully be physiologically monitored together with serial assessment of biomarkers aiming at a favorable cardiac outcome by giving the timely diagnosis and intervention.
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http://dx.doi.org/10.1111/j.1442-200X.2012.03592.xDOI Listing
August 2012

[Legionella contamination risk factors in non-circulating hot spring water].

Kansenshogaku Zasshi 2009 Jan;83(1):36-44

Ehime Prefectural Institute of Public Health and Environmental Science.

We examined water from 182 non-circulating hot spring bathing facilities in Japan for possible Legionella occurrence from June 2005 to December 2006, finding Legionella-positive cultures in 119 (29.5%) of 403 samples. Legionellae occurrence was most prevalent in bathtub water (39.4%), followed by storage tank water (23.8%), water from faucets at the bathtub edge (22.3%), and source-spring water (8.3%), indicating no statistically significant difference, in the number of legionellae, having an overall mean of 66 CFU/100mL. The maximum number of legionellae in water increased as water was sampled downstream:180 CFU/100 mL from source spring, 670 from storage tanks, 4,000 from inlet faucets, and 6,800 from bathtubs. The majority--85.7%--of isolated species were identified as L. pneumophila : L. pneumophila serogroup (SG) 1 in 22%, SG 5 in 21%, and SG 6 in 22% of positive samples. Multivariate logistic regression models used to determine the characteristics of facilities and sanitary management associated with Legionella contamination indicated that legionellae was prevalent in bathtub water under conditions where it was isolated from inlet faucet/pouring gate water (odds ratio [OR] = 6.98, 95% confidence interval [CI] = 2.14 to 22.8). Risk of occurrence was also high when the bathtub volume exceeded 5 m3 (OR = 2.74, 95% CI = 1.28 to 5.89). Legionellae occurrence was significantly reduced when the bathing water pH was lower than 6.0 (OR = 0.12, 95% CI = 0.02 to 0.63). Similarly, occurrence was rare in inlet faucet water or the upper part of the plumbing system for which pH was lower than 6.0 (OR = 0.06, 95% CI = 0.01 to 0.48), and when the water temperature was maintained at 55 degrees C or more (OR = 0.10, 95% CI = 0.01 to 0.77). We also examined the occurrence of amoeba, Mycobacterium spp., Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus in water samples.
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http://dx.doi.org/10.11150/kansenshogakuzasshi.83.36DOI Listing
January 2009

Cyclic strain stimulates early growth response gene product 1-mediated expression of membrane type 1 matrix metalloproteinase in endothelium.

Lab Invest 2002 Jul;82(7):949-56

Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA.

Summary: Matrix metalloproteinases (MMPs) are hypothesized to be involved in the processes of endothelial cell (EC) migration and matrix remodeling during angiogenesis. Although hemodynamic forces (such as blood pressure, wall tension, and shear stress) are considered to be strong stimuli for angiogenesis, the role of hemodynamic forces on the regulation of MMPs including membrane type 1 matrix metalloproteinase (MT1-MMP) has not been fully elucidated. To study this, rat microvascular EC were exposed to 60 cycles/minute of 24% maximum strain for up to 24 hours. MT1-MMP mRNA and protein increased in a time-dependent manner through 24 hours of exposure to cyclic strain. Cyclic strain induced early growth response gene product (Egr-1) mRNA and protein within 1 hour. A specific nucleoprotein complex was formed when an oligonucleotide containing binding sites for Sp1 and Egr-1 was incubated with nuclear extracts from EC exposed to 1 hour of cyclic strain. Antibodies to Egr-1 completely supershifted this complex. Increased binding of Egr-1 by cyclic strain to the MT1-MMP promoter correlated with enhanced transcriptional activity. These results suggest that cyclic strain up-regulates the Egr-1-mediated expression of MT1-MMP in rat microvascular EC, emphasizing the importance of hemodynamic forces in the regulation of MT1-MMP in vivo.
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http://dx.doi.org/10.1097/01.lab.0000020408.77307.e9DOI Listing
July 2002

Transcription factor Sp1 phosphorylation induced by shear stress inhibits membrane type 1-matrix metalloproteinase expression in endothelium.

J Biol Chem 2002 Sep 1;277(38):34808-14. Epub 2002 Jul 1.

Department of Surgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA.

Membrane type 1-matrix metalloproteinase (MT1-MMP) plays a key role in endothelial cell migration, matrix remodeling, and angiogenesis. Previous studies demonstrated that a mechanical force, cyclic strain, increases MT1-MMP expression by displacing Sp1 with increased Egr-1 expression and binding to the promoter site. However, the effect of shear stress (SS) on MT1-MMP expression is poorly understood. Although Egr-1 mRNA transcription and protein was induced (7.6-fold) in response to SS (n = 5, 0-8 h, p < 0.05), SS decreased MT1-MMP mRNA transcription and protein levels in a time-dependent fashion (10, 50, and 90% reduction at 1, 4, and 8 h, respectively; n = 5, p < 0.05). Egr-1 protein was increased after SS and cyclic strain, but Sp1 was serine-phosphorylated only after SS. SS increased Sp1 DNA binding (3.8-, 5.8-, and 2.4-fold increase at 1, 4, and 8 h, respectively; n = 5, p < 0.05) that was inhibitable by calf intestinal phosphatase. Thus, SS inhibits MT1-MMP expression despite Egr-1 up-regulation by inducing the serine phosphorylation of Sp1, which in turn increases its binding affinity for its site on the MT1-MMP promoter, reducing the ability of Egr-1 to displace it. These data illustrate the complex control of microvascular endothelial cell MT1-MMP expression in response to distinct environmental stimuli (cyclic strain versus shear stress), consisting of both the modulation of specific transcription factor expression (Egr-1) as well as transcription factor post-translational modification (serine phosphorylation of Sp1).
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http://dx.doi.org/10.1074/jbc.M205417200DOI Listing
September 2002