Development of inorganic and organic hybrid nanocoating based on carbon nanotubes for corrosion resistance

In this study, we report the synthesis and characterization of novel hybrid nanocoating based on carbon nanotubes (CNTs) on anodized aluminum surfaces (AAO). The hybrid nanocoating was deposited by number of methods which include spray coating, spin coating and dip coating. The bonding of nanocoating with metal surface is an important parameter for successful modification of the metal surfaces. The improved adhesion of nanocoating on metal surfaces could be attributed to chemical bonding of sol-gel nanocoating with anodized surfaces. The nanocoated anodized aluminum surfaces showed superior adhesion and excellent anticorrosive properties. The nanocoated panels showed enhanced galvanic protection comparable to 80% of titanium metal as determined by galvanic corrosion measurements. It also showed higher thermal conductivities than stainless steel and bare anodized surfaces.

Elastic differential cross sections for C₄F₆ isomers in the 1.5-200 eV energy electron impact: similarities with six fluorine containing molecules and evidence of F-atom like scattering

We report absolute elastic differential cross sections for electron interactions with the C4F6 isomers, hexafluoro-1,3-butadiene (1,3-C4F6), hexafluoro-2-butyne (2-C4F6), and hexafluorocyclobutene (c-C4F6). The incident electron energy range is 1.5-200 eV, and the scattered electron angular range for the differential measurements varies from 15° to 150°. In all cases the absolute scale of the differential cross section was set using the relative flow technique, with helium as the reference species. Atomic-like behaviour in these scattering systems is shown here for the first time, and is further investigated by comparing the elastic cross sections for the C4F6 isomers with other fluorinated molecules, such as SF6 and CnF6 (n = 2, 3, and 6). We note that for all the six-F containing molecules, the scattering process for electron energies above 30 eV is indistinguishable. Finally, we report results for calculations of elastic differential cross sections for electron scattering from each of these isomers, within an optical potential method and assuming a screened corrected independent atom representation. The level of agreement between these calculations and our measurements is found to be quite remarkable in all cases.

Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement

Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T₂* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution.

MARCH5-mediated quality control on acetylated Mfn1 facilitates mitochondrial homeostasis and cell survival

Mitochondrial dynamics and quality control have a central role in the maintenance of cellular integrity. Mitochondrial ubiquitin ligase membrane-associated RING-CH (MARCH5) regulates mitochondrial dynamics. Here, we show that mitochondrial adaptation to stress is driven by MARCH5-dependent quality control on acetylated Mfn1. Under mitochondrial stress conditions, levels of Mfn1 were elevated twofold and depletion of Mfn1 sensitized these cells to apoptotic death. Interestingly, overexpression of Mfn1 also promoted cell death in these cells, indicating that a fine tuning of Mfn1 levels is necessary for cell survival. MARCH5 binds Mfn1 and the MARCH5-dependent Mfn1 ubiquitylation was significantly elevated under mitochondrial stress conditions along with an increase in acetylated Mfn1. The acetylation-deficient K491R mutant of Mfn1 showed weak interaction with MARCH5 as well as reduced ubiquitylation. Neither was observed in the acetylation mimetic K491Q mutant. In addition, MARCH5-knockout mouse embryonic fibroblast and MARCH5(H43W)-expressing HeLa cells lacking ubiquitin ligase activity experienced rapid cell death upon mitochondrial stress. Taken together, a fine balance of Mfn1 levels is maintained by MARCH5-mediated quality control on acetylated Mfn1, which is crucial for cell survival under mitochondria stress conditions.

Diagnostic value of computed tomography for staging of clinical T1 gastric cancer

BACKGROUND

T1 gastric cancer can be diagnosed only by endoscopy and is almost curable by local treatment. It has been unclear how a multidetector-row computed tomography (CT) evaluation is valuable for clinical T1 patients.

METHODS

Patients with clinical T1 disease, as diagnosed by endoscopy and treated with endoscopic submucosal dissection (ESD) or surgery between October 2000 and October 2007, were examined. The efficacy of CT was evaluated by the reversal rate of endoscopic T1 by CT, the incidence of clinical M1 disease, and the accuracy of diagnosing pathological N+ disease in patients who received surgery. To confirm metachronous distant and nodal metastases, the disease-free survival (DFS) also was evaluated.

RESULTS

A total of 761 patients, 236 treated by ESD and 525 treated with surgery, were examined. None of the patients had an endoscopic diagnosis of clinical T1 reversed by CT. No clinical M1 disease was found. Among the 525 patients who underwent surgery, 8 showed clinical N+ disease (1.5 %), while 47 demonstrated pathological N+ disease (8.9 %). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive values were 90.3, 4.3, 98.7, 25, and 91.3 %, respectively. The 5-year DFS rate was 93.6 % (95 % confidence interval 91.4-95.8 %).

CONCLUSIONS

The present study suggests that diagnostic value of CT is limited for staging of clinical T1 gastric cancer patients, because the reversal rate of endoscopic T1 by CT was very low, clinical M1 disease was rare, the diagnosis of N+ status was unreliable, and metachronous M1 and N+ findings were rare.

Cortical thickness and hippocampal shape in pure vascular mild cognitive impairment and dementia of subcortical type

BACKGROUND AND PURPOSE

The progression pattern of brain structural changes in patients with isolated cerebrovascular disease (CVD) remains unclear. To investigate the role of isolated CVD in cognitive impairment patients, patterns of cortical thinning and hippocampal atrophy in pure subcortical vascular mild cognitive impairment (svMCI) and pure subcortical vascular dementia (SVaD) patients were characterized.

METHODS

Forty-five patients with svMCI and 46 patients with SVaD who were negative on Pittsburgh compound B (PiB) positron emission tomography imaging and 75 individuals with normal cognition (NC) were recruited.

RESULTS

Compared with NC, patients with PiB(-) svMCI exhibited frontal, language and retrieval type memory dysfunctions, which in patients with PiB(-) SVaD were further impaired and accompanied by visuospatial and recognition memory dysfunctions. Compared with NC, patients with PiB(-) svMCI exhibited cortical thinning in the frontal, perisylvian, basal temporal and posterior cingulate regions. This atrophy was more prominent and extended further toward the lateral parietal and medial temporal regions in patients with PiB(-) SVaD. Compared with NC subjects, patients with PiB(-) svMCI exhibited hippocampal shape deformities in the lateral body, whilst patients with PiB(-) SVaD exhibited additional deformities within the lateral head and inferior body.

CONCLUSIONS

Our findings suggest that patients with CVD in the absence of Alzheimer's disease pathology can be demented, showing cognitive impairment in multiple domains, which is consistent with the topography of cortical thinning and hippocampal shape deformity.

Erythritol alters microstructure and metabolomic profiles of biofilm composed of Streptococcus gordonii and Porphyromonas gingivalis

The effects of sugar alcohols such as erythritol, xylitol, and sorbitol on periodontopathic biofilm are poorly understood, though they have often been reported to be non-cariogenic sweeteners. In the present study, we evaluated the efficacy of sugar alcohols for inhibiting periodontopathic biofilm formation using a heterotypic biofilm model composed of an oral inhabitant Streptococcus gordonii and a periodontal pathogen Porphyromonas gingivalis. Confocal microscopic observations showed that the most effective reagent to reduce P. gingivalis accumulation onto an S. gordonii substratum was erythritol, as compared with xylitol and sorbitol. In addition, erythritol moderately suppressed S. gordonii monotypic biofilm formation. To examine the inhibitory effects of erythritol, we analyzed the metabolomic profiles of erythritol-treated P. gingivalis and S. gordonii cells. Metabolome analyses using capillary electrophoresis time-of-flight mass spectrometry revealed that a number of nucleic intermediates and constituents of the extracellular matrix, such as nucleotide sugars, were decreased by erythritol in a dose-dependent manner. Next, comparative analyses of metabolites of erythritol- and sorbitol-treated cells were performed using both organisms to determine the erythritol-specific effects. In P. gingivalis, all detected dipeptides, including Glu-Glu, Ser-Glu, Tyr-Glu, Ala-Ala and Thr-Asp, were significantly decreased by erythritol, whereas they tended to be increased by sorbitol. Meanwhile, sorbitol promoted trehalose 6-phosphate accumulation in S. gordonii cells. These results suggest that erythritol has inhibitory effects on dual species biofilm development via several pathways, including suppression of growth resulting from DNA and RNA depletion, attenuated extracellular matrix production, and alterations of dipeptide acquisition and amino acid metabolism.