Development of Zn–Mg–Ca Biodegradable Dual-Phase Alloys

In this paper, in order to achieve the development of a novel biodegradable dual-phase alloy in a Ca–Mg–Zn system, the establishment of the control strategy of degradation behavior of alloys composed of two phases was attempted by the control of alloy composition, constituent phases, and microstructure. By combining two phases with different dissolution behavior, biodegradable alloys are expected to exhibit multiple functions. For example, combining a suitable slow dissolving phase with a faster dissolving second phase may allow for dynamical concavities formation during immersion on the surface of the alloy, assisting the invasion and establishment of bone cells. Without the careful control of the microstructure, however, there is a risk that such dual-phase alloy rapidly collapses before the healing of the affected area. In this study, ten two-phase alloys consisting of various different phases were prepared and their degradation behaviors were examined. Consequently, it was found that by combining the IM3 and IM1 intermetallic phases with the compositions of Ca2Mg5Zn13 and Ca3Mg4.6Zn10.4, the expected degradation behavior can be obtained.Hagihara K., Shakudo S., Tokunaga T., et al. Development of Zn–Mg–Ca Biodegradable Dual-Phase Alloys. Metals 13, 1095 (2023); https://doi.org/10.3390/met13061095

Protein Transduction Method for Cerebrovascular Disorders

Many studies have shown that a motif of 11 consecutive arginines (11R) is one of the most effective protein transduction domains (PTD) for introducing proteins into the cell membrane. By conjugating this &#34;11R&#34;, all sorts of proteins can effectively and harmlessly be transferred into any kind of cell. We therefore examined the transduction efficiency of 11R in cerebral arteries and obtained results showing that 11R fused enhanced green fluorescent protein (11R-EGFP) immediately and effectively penetrated all layers of the rat basilar artery (BA), especially the tunica media. This method provides a revolutionary approach to cerebral arteries and ours is the first study to demonstrate the successful transductionof a PTD fused protein into the cerebral arteries. In this review, we present an outline of our studies and other key studies related to cerebral vasospasm and 11R, problems to be overcome, and predictions regarding future use of the 11R protein transduction method for cerebral vasospasm (CV).</p

Octacosanol Attenuates Disrupted Hepatic Reactive Oxygen Species Metabolism Associated with Acute Liver Injury Progression in Rats Intoxicated with Carbon Tetrachloride

We examined whether octacosanol, the main component of policosanol, attenuates disrupted hepatic reactive oxygen species metabolism associated with acute liver injury progression in rats intoxicated with carbon tetrachloride (CCl4). In rats intoxicated with CCl4 (1 ml/kg, i.p.), the activities of serum transaminases increased 6 h after intoxication and further increased at 24 h. In the liver of CCl4-intoxicated rats, increases in lipid peroxide (LPO) concentration and myeloperoxidase activity and decreases in superoxixde dismutase activity and reduced glutathione (GSH) concentration occurred 6 h after intoxication and these changes were enhanced with an increase in xanthine oxidase activity and a decrease in catalase activity at 24 h. Octacosanol (10, 50 or 100 mg/kg) administered orally to CCl4-intoxicated rats at 6 h after intoxication attenuated the increased activities of serum transaminases and the increased hepatic myeloperoxidase and xanthine oxidase activities and LPO concentration and the decreased hepatic superoxide dismutase and catalase activities and GSH concentration found at 24 h after intoxication dose-dependently. Octacosanol (50 or 100 mg/kg) administered to untreated rats decreased the hepatic LPO concentration and increased the hepatic GSH concentration. These results indicate that octacosanol attenuates disrupted hepatic reactive oxygen species metabolism associated with acute liver injury progression in CCl4-intoxicated rats

Self-joining of Y-TZP by flash event under an AC electric field

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Prophylactic Ligation of the Innominate Artery and Creation of Tracheostomy in a Neurologically Impaired Girl: A Case Report

Tracheoinnominate artery fistula is known as a potentially fatal complication for patients who depend on tracheostomy or tracheoesophageal diversion. Since the bleeding from a TIF is often difficult to control, preventative procedures are recommended to avoid this complication. An 11-year-old girl with hypoxic-ischemic encephalopathy and scoliosis developed tracheal stenosis caused by compression from the innominate artery. Respiratory control with intubation through the tracheal stenosis was needed, and the patient was at high risk for developing a TIF. She underwent ligation of the innominate artery at tracheostomy. Subsequent tracheostomy revealed a widened tracheal lumen and no further complications. Prophylactic ligation of the innominate artery and creation of tracheostomy might be considered as a valid option for patients at high risk of developing TIF

Novel 3D-CT evaluation of carotid stent volume: greater chronological expansion of stents in patients with vulnerable plaques

Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors. Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed. Stent volume gradually increased in each case and had increased by 1.04-1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P < 0.05). A 3D-CT examination is useful for precisely measuring stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period

Dual-Stimuli-Responsive Probes for Detection of Ovarian Cancer Cells and Quantification of Both pH and Enzyme Activity

Many physiological processes involve multiple coordinated chemical and/or biological events. Therefore, it is considered urgent to develop dual-responsive probes for a more comprehensive understanding of the synergistic effects between multiple analytes in complex cellular environments. In this study, we developed a dual-responsive probe βgal-BP-PMB (β-galactosyl–3, 3′-dihydroxy-2, 2′-bipyridyl–p-methoxybenzyl), the photoluminescence of which can be activated by β-galactosidase (β-gal) and acidic conditions. The overexpression of β-gal is an important feature of senescent and ovarian cancer cells. Single-input activatable probes for detecting β-gal activity in ovarian cancer cells can induce a false positive response from senescent cells. Because the lysosomal pH in senescent cells is increased, probe βgal-BP-PMB can be specifically activated in ovarian cancer cells, but silenced in senescent cells. Probe βgal-BP-PMB has a small molecular size, high sensitivity towards targeted stimuli and unique ratiometric properties, thereby enabling the quantification of both pH and enzyme activity. Such dual-responsive probes could earn a unique place in the field of bioimaging, where multiple analytes should be accurately and simultaneously monitored

Quantitative estimation of kink-band strengthening in an Mg–Zn–Y single crystal with LPSO nanoplates

Kink-band strengthening was first quantitatively evaluated using an Mg–Zn–Y single crystal containing long-period stacking ordered (LPSO) nanoplates. The ability of a kink-band boundary to act as a barrier that hinders the motion of dislocations is high and comparable to that of a general random grain boundary. Nevertheless, a kink-band boundary is regarded as a simple tilt boundary in the dislocation model. One reason for the anomalous ability of kink-band boundary acting as barriers is related to its peculiar hierarchical structure, in which many small kink bands with high crystal rotation angles accumulate in a localized region.Hagihara K., Ueyama R., Tokunaga T., et al. Quantitative estimation of kink-band strengthening in an Mg–Zn–Y single crystal with LPSO nanoplates. Materials Research Letters, 9, 11, 467. https://doi.org/10.1080/21663831.2021.1974593

Noninvasive and safe cell viability assay for Euglena gracilis using natural food pigment

Noninvasive and safe cell viability assay is required in many fields such as regenerative medicine, genetic engineering, single-cell analysis, and microbial food culture. In this case, a safe and inexpensive method which is a small load on cells and the environment is preferable without requiring expensive and space-consuming equipment and a technician to operate. We examined eight typical natural food pigments to find Monascus pigment (MP) or anthocyanin pigment (AP) works as a good viability indicator of dye exclusion test (DET) for Euglena gracilis which is an edible photosynthetic green microalga. This is the first report using natural food pigments as cell viability assay. Euglena gracilis stained by MP or AP can be visually judged with a bright field microscope. This was spectrally confirmed by scan-free, non-invasive absorbance spectral imaging A(x, y, λ) microscopy of single live cells and principal component analysis (PCA). To confirm the ability of staining dead cells and examine the load on the cells, these two natural pigments were compared with trypan blue (TB) and methylene blue (MP), which are synthetic dyes conventionally used for DET. As a result, MP and AP had as good ability of staining dead cells treated with microwave as TB and MB and showed faster and more uniform staining for dead cells in benzalkonium chloride than them. The growth curve and the ratio of dead cells in the culture showed that the synthetic dyes inhibit the growth of E. gracilis, but the natural pigments do not. As the cell density increased, however, AP increased the ratio of stained cells, which was prevented by the addition of glucose. MP can stain dead cells in a shorter time than AP, while AP is more stable in color against long-term irradiation of intense light than MP. Due to the low toxicity of these pigments, viability of cells in culture can be monitored with them over a long period