Lamb wave line sensing for crack detection in a welded stiffener

This paper proposes a novel Lamb wave line sensing technique for crack detection in a welded stiffener. The proposed technique overcomes one of the biggest technical challenges of Lamb wave crack detection for real structure applications: crack-induced Lamb waves are often mixed with multiple reflections from complex waveguides. In particular, crack detection in a welded joint, one of the structural hot spots due to stress concentration, is accompanied by reflections from the welded joint as well as a crack. Extracting and highlighting crack-induced Lamb wave modes from Lamb wave responses measured at multi-spatial points along a single line can be accomplished through a frequency-wavenumber domain analysis. The advantages of the proposed technique enable us not only to enhance the crack detectability in the welded joint but also to minimize false alarms caused by environmental and operational variations by avoiding the direct comparison with the baseline data previously accumulated from the pristine condition of a target structure. The proposed technique is experimentally and numerically validated in vertically stiffened metallic structures, revealing that it successfully identifies and localizes subsurface cracks, regardless of the coexistence with the vertical stiffener.open0

Effect of Combination Therapy with Sodium Ozagrel and Panax Ginseng on Transient Cerebral Ischemia Model in Rats

Sodium ozagrel (SO) prevents platelet aggregation and vasoconstriction in the cerebral ischemia. It plays an important role in the prevention of brain damage induced by cerebral ischemia/reperfusion. Recently, many animal studies have suggested that the Panax ginseng (PG) has neuroprotective effects in the ischemic brain. In this study, we assessed the neuroprotective effects that come from a combination therapy of SO and PG in rat models with middle cerebral artery occlusion (MCAO). Animals with MCAO were assigned randomly to one of the following four groups: (1) control (Con) group, (2) SO group (3 mg/kg, intravenously), (3) PG group (200 mg/kg, oral feeding), and (4) SO + PG group. The rats were subjected to a neurobehavior test including adhesive removal test and rotarod test at 1, 3, 7, 10, and 15 days after MCAO. The cerebral ischemic volume was quantified by Metamorph imaging software after 2-3-5-triphenyltetrazolium (TTC) staining. The neuronal cell survival and astrocytes expansion were assessed by immunohistofluorescence staining. In the adhesive removal test, the rats of PG or SO + PG group showed significantly better performance than those of the control group (Con: 88.1 ± 24.8, PG: 43.6 ± 11, SO + PG: 11.8 ± 7, P < .05). Notably, the combination therapy group (SO + PG) showed better performance than the SO group alone (SO: 56 ± 12, SO + PG: 11.8 ± 7, P < .05). In TTC staining for infarct volume, cerebral ischemic areas were also significantly reduced in the PG group and SO + PG group (Con: 219 ± 32, PG: 117 ± 8, SO + PG: 99 ± 11, P < .05). Immunohistofluorescence staining results showed that the group which received SO + PG group therapy had neuron cells in the normal range. They also had a low number of astrocytes and apoptotic cells compared with the control or SO group in the peri-infarction area. During astrocytes staining, compared to the SO + PG group, the PG group showed only minor differences in the number of NeuN-positive cells and quantitative analysis of infarct volume. In conclusion, these studies showed that in MCAO rat models, the combination therapy with SO and PG may provide better neuroprotective effects such as higher neuronal cell survival and inhibition of astrocytes expansion than monotherapy with SO alone

Acute Obstructive Cholangitis after Transarterial Chemoembolization: the Effect of Percutaneous Transhepatic Removal of Tumor Fragment

Acute obstructive cholangitis due to the migration of necrotized tumor fragment is a rare complication occurring after a transarterial chemoembolization. The percutaneous tumor removal procedure following percutaneous transhepatic biliary drainage is an appropriate treatment over endoscopic removal for the relief of acute cholangitis in this case. Following this serial management, no invasive hepatocellular carcinoma of the bile duct recurred after two years of follow-up

A Pilot Study for the Neuroprotective Effect of Gongjin-dan on Transient Middle Cerebral Artery Occlusion-Induced Ischemic Rat Brain

In this study, we investigated whether gongjin-dan improves functional recovery and has neuroprotective effects on reducing the infarct volume after transient middle cerebral artery occlusion (MCAo). Infarct volume was measured using TTC staining and glucose utilization by F-18 FDG PET. Functional improvement was evaluated with the Rota-rod, treadmill, Garcia score test, and adhesive removal test. At 14 days after MCAo, neuronal cell survival, astrocytes expansion, and apoptosis were assessed by immunohistofluorescence staining in the peri-infarct region. Also, the expression of neurotrophic factors and inflammatory cytokines such as VEGF, BDNF, Cox-2, TNF-α, IL-1β, and IL-1α was measured in ischemic hemisphere regions. The gongjin-dan-treated group showed both reduced infarct volume and increased glucose utilization. Behavior tests demonstrated a significant improvement compared to the control. Also in the gongjin-dan treated group, NeuN-positive cells were increased and number of astrocytes, microglia, and apoptotic cells was significantly decreased compared with the control group in the ischemic peri-infarct area. Furthermore, the expression of VEGF and BDNF was increased and level of Cox-2, TNF-α, IL-1β, and IL-1α was decreased. These results suggest that gongjin-dan may improve functional outcome through the rapid restoration of metabolism and can be considered as a potential neuroprotective agent

SARS-CoV-2 Omicron variant causes brain infection with lymphoid depletion in a mouse COVID-19 model

Background The Omicron variant has become the most prevalent SARS-CoV-2 variant. Omicron is known to induce milder lesions compared to the original Wuhan strain. Fatal infection of the Wuhan strain into the brain has been well documented in COVID-19 mouse models and human COVID-19 cases, but apparent infections into the brain by Omicron have not been reported in human adult cases or animal models. In this study, we investigated whether Omicron could spread to the brain using K18-hACE2 mice susceptible to SARS-CoV-2 infection. Results K18-hACE2 mice were intranasally infected with 1 × 105 PFU of the original Wuhan strain and the Omicron variant of SARS-CoV-2. A follow-up was conducted 7days post infection. All Wuhan-infected mice showed > 20% body weight loss, defined as the lethal condition, whereas two out of five Omicron-infected mice (40%) lost > 20% body weight. Histopathological analysis based on H&E staining revealed inflammatory responses in the brains of these two Omicron-infected mice. Immunostaining analysis of viral nucleocapsid protein revealed severe infection of neuron cells in the brains of these two Omicron-infected mice. Lymphoid depletion and apoptosis were observed in the spleen of Omicron-infected mice with brain infection. Conclusion Lethal conditions, such as severe body weight loss and encephalopathy, can occur in Omicron-infected K18-hACE2 mice. Our study reports, for the first time, that Omicron can induce brain infection with lymphoid depletion in the mouse COVID-19 model

Pretransplant malnutrition, inflammation, and atherosclerosis affect cardiovascular outcomes after kidney transplantation

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background Malnutrition, inflammation, and atherosclerosis (MIA) syndrome is associated with a high mortality rate in patients with end-stage renal disease. However, the clinical relevance of MIA syndrome in kidney transplantation (KT) recipients remains unknown. Methods We enrolled 1348 adult KT recipients. Recipients were assessed based on serum albumin, cholesterol, or body mass index for the malnutrition factor and C-reactive protein level for the inflammation factor. Any history of cardiovascular (CV), cerebrovascular, or peripheral vascular disease satisfied the atherosclerosis factor. Each MIA factors were assessed by univariate analysis and we calculated an overall risk score by summing up scores for each independent variable. The enrolled patients were divided into 4 groups depending on the MIA score (0, 2–4, 6, 8–10). Results The patients with higher MIA score showed worse outcome of fatal/non-fatal acute coronary syndrome (ACS) (p < 0.001) and composite outcomes of ACS and all-cause mortality (p < 0.001) than with the lower MIA score. In multivariate analysis, ACS showed significantly higher incidence in the MIA score 8-10 group than in the MIA score 0 group (Hazard ratio 6.12 95 % Confidence interval 1.84–20.32 p = 0.003). Conclusions The presence of MIA factors before KT is an independent predictor of post-transplant CV outcomes