UV Light-Generated Superhydrophilicity of a Titanium Surface Enhances the Transfer,Diffusion and Adsorption of Osteogenic Factors from a Collagen Sponge

It is a significant challenge for a titanium implant, which is a bio-inert material, to recruit osteogenic factors, such as osteoblasts, proteins and blood effectively when these are contained in a biomaterial. The objective of this study was to examine the effect of ultraviolet (UV)-treatment of titanium on surface wettability and the recruitment of osteogenic factors when they are contained in an atelocollagen sponge. UV treatment of a dental implant made of commercially pure titanium was performed with UV-light for 12 min immediately prior to the experiments. Superhydrophilicity on dental implant surfaces was generated with UV-treatment. The collagen sponge containing blood, osteoblasts, or albumin was directly placed on the dental implant. Untreated implants absorbed only a little blood from the collagen sponge, while the UV-treated implants absorbed blood rapidly and allowed it to spread widely, almost over the entire implant surface. Blood coverage was 3.5 times greater for the UV-treated implants (p < 0.001). Only 6% of the osteoblasts transferred from the collagen sponge to the untreated implants, whereas 16% of the osteoblasts transferred to the UV-treated implants (p < 0.001). In addition, a weight ratio between transferred albumin on the implant and measured albumin adsorbed on the implant was 17.3% in untreated implants and 38.5% in UV-treated implants (p < 0.05). These results indicated that UV treatment converts a titanium surface into a superhydrophilic and bio-active material, which could recruite osteogenic factors even when they were contained in a collagen sponge. The transfer and subsequent diffusion and adsorption efficacy of UV-treated titanium surfaces could be useful for bone formation when titanium surfaces and osteogenic factors are intervened with a biomaterial.     

Preparation of silica fibers and non-woven cloth by electrospinning

Silica fibers, which can potentially be used as filters and media for catalysts immobilization, were successfully spun via electrospinning process with precursor prepared through the sol–gel synthesis. Spinnable sols can be obtained only when the molar ratio of water to TEOS is less than 2 which is consistent with the retrospective results derived for other spinning methods. It was confirmed for the first time that the reaction time can be drastically reduced by introducing humidified air, controlled by KCl saturated aqueous solution, during sol–gel process. The size of obtained silica fibers is about 4.5 μm and has a certain degree of flexibility and mechanical strength. Although the specific surface area of as spun fiber was 7.7 m²/g, which is apparently small comparing to generic silica, treatment by boiling water only for 5 min could increase the specific surface area to be about 500 m²/g.     

Synthesis of Dense Lead Titanate Ceramics with Submicrometer Grains by Spark Plasma Sintering

Dense PbTiO₃ ceramics consisting of submicrometer-sized grains were prepared using the spark-plasma-sintering (SPS) method. Hydrothermally prepared PbTiO₃ (0.1 μm) was used as a starting powder. The powder was densified to ≳98% of the theoretical X-ray density by the SPS process. The average grain size of the spark-plasma-sintered ceramics (SPS ceramics) was ≲1 μm, even after sintering at 900°–1100°C, because of the short sintering period (1–3 min). The measured permittivity of the SPS ceramics showed almost no frequency dependence over the range 10¹–10⁶ Hz, mainly because pores were absent from the ceramics. The coercive field of the SPS ceramics was somewhat higher than that of conventionally sintered ceramics, which could be attributed to the small-grained microstructures of the SPS ceramics.     

A novel method for determining vitamin B1 in a wide variety of foodstuffs with or without polyphenols

Certain foodstuffs exhibit matrix interference effects on the vitamin B₁ analysis prescribed in the official methods of the European Union, AOAC International, and Japan. In this study, we demonstrated that one of the problematic polyphenols in green tea or cocoa was tannin. For these matrices, thiamine was found to interact with tannin in the extraction step and was thus removed by filtration as a residue. To resolve the matrix interference, we proposed lowering the pH of the extraction solution by adding hydrochloric acid after the enzyme reaction. High precision (2–3% RSDr) and good recovery (98.3–103%) were obtained with reference materials using the proposed method. We also confirmed the equivalence of the obtained data from the proposed method and the Japanese official method for nutritional labeling. From these results, the method was found to be effective for vitamin B₁ analysis regardless of the presence of interference matrices.     

Unkeito Suppresses RANKL-Mediated Osteoclastogenesis via the Blimp1–Bcl6 and NF-κB Signaling Pathways and Enhancing Osteoclast Apoptosis

Osteoporosis is a common bone disease, particularly in menopausal women. Herein, we screened four Kampo medicines (Unkeito (UKT), Kamishoyosan (KSS), Kamikihito (KKT), and Ninjinyoeito (NYT)), frequently used to treat menopausal syndromes, for their effects on receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclast differentiation in RAW 264 cells. Considering that UKT exhibited the most potent effect, we examined its effect on RANKL-induced osteoclastogenesis, the induction of osteoclast apoptosis, and the mechanisms underlying its effects. UKT inhibits RANKL-induced osteoclast differentiation in the early stage and decreases osteoclast-related genes, including tartrate-resistant acid phosphatase (Trap), dendritic cell-specific transmembrane protein (Dcstamp), matrix metalloproteinase-9 (Mmp9), and cathepsin K (Ctsk). Specifically, UKT inhibits the nuclear factor of activated T cells 1 (NFATc1), which is essential for osteoclastogenesis. UKT increases Bcl6, which antagonizes NFATc1 and Dc-stamp, thereby blocking the progression of osteoclasts to maturation. UKT also decreased nuclear translocation by downregulating the activity of p65/NF-κB. In addition, UKT enhances mononuclear osteoclast apoptosis via activation of caspase-3. Herein, we demonstrate that UKT suppresses RANKL-mediated osteoclastogenesis via the Blimp1–Bcl6 and NF-κB signaling pathways and enhances mononuclear osteoclast apoptosis. Furthermore, UKT prevents bone loss in OVX mice. Thus, UKT might be a potential therapeutic agent for postmenopausal osteoporosis.     

Mechanism and clinical usefulness of S4-S1 interval in heart failure associated with left ventricular inflow pattern]

Technetium-99m-tetrofosmin, a myocardial perfusion imaging agent was used for estimation of cardiac output by means of first-pass radionuclide angiography performed in the anterior projection. Region of interests (ROIs) were assigned over right ventricle, left ventricle and whole chest, and time activity curves (TACs) were obtained. Cardiac output indices (COIs) were calculated by the following equation; COI = p3/2. Qc/[symbol: see text] A(s)ds, where p = number of pixels of the ventricular ROI, Qc = the peak count rate of the TAC obtained from the whole chest's ROI and [symbol: see text] A(s)ds = the area under ventricular TAC. The COI (y) determined by ROI over the left ventricle yield the best correlation with the cardiac output by conventional radionuclide method (x) (y = 0.0381x + 6.22, r = 0.828, n = 48, p < 0.001). In conclusion, cardiac output can be easily measured with first pass data using myocardial perfusion imaging agent.     

Materials evaluation of diffusion bonded steel bar and its impact characteristics

When we apply non-destructive test for evaluating the soundness of weld joints it is necessary to know the mechanical properties of the joints by destructive test. In this paper we tried to obtain the correlation between the data by ultrasonic C-scope method and the absorbed energy by Charpy impact test for diffusion bonded steel bars. The surface roughness of specimens (materials: S25C, mild steel) used for the diffusion bonding was changed into several steps by machining and the diffusion bonding was performed on five kinds of combinations of the surface roughness. Through this process we obtained the diffusion bonds whose ratio of non-bonded area was different. In the ultrasonic test we used the frequency of 10 MHz and a transducer of 12.7 mm in diameter. The ratio of non-bonded area is obtained by using C-scope method by immersion testing, and this depended on the threshold echo level when we binarized the images of C-scope presentation and the surface roughness of the specimen. The lower the threshold echo level, the larger the ratio of non-bonded area. The absorbed energy depended on the ratio of non-bonded area. It is made clear that the proper threshold echo level should be selected for evaluating the soundness of diffusion bonds by ultrasonic test. Moreover, when the transition liquid phase diffusion bonding was performed on SD345 (deformed reinforcing steel bar) using Ni amorphous foil as an insert metal the absorbed energy also decreased with the increase in the ratio of flaw area obtained by ultrasonic test, though no change in the tensile strength was observed.     

HoneyCirculator: distributing credential honeytoken for introspection of web-based attack cycle

A web user who falsely accesses a compromised website is usually redirected to an adversary’s website and is forced to download malware after being exploited. Additionally, the adversary steals the user’s credentials by using information-leaking malware. The adversary may also try to compromise public websites owned by individual users by impersonating the website administrator using the stolen credentials. These compromised websites then become landing sites for drive-by download malware infection. Identifying malicious websites using crawling techniques requires a large amount of resources and time. To monitor the web-based attack cycle for effective detection and prevention, we propose a monitoring system called HoneyCirculator based on a honeytoken, which actively leaks bait credentials and lures adversaries to our decoy server that behaves like a compromised web content management system. To recursively analyze attack phases on the web-based attack cycle, our proposed system involves collecting malware, distributing bait credentials, monitoring fraudulent access, and inspecting compromised web content. It can instantly discover unknown malicious entities without conducting large-scale web crawling because of the direct monitoring behind the compromised web content management system. Our proposed system enables continuous and stable monitoring for about one year. In addition, almost all the malicious websites we discovered had not been previously registered in public blacklists.     

Image extraction of particle concentration at the plug front using 3D wavelets and comparison with LDV

Particle concentration distribution images of a dense two-phase solid/air (plug) flow have been obtained at 10-ms intervals in a horizontal pipeline using capacitance computed tomography. The three-dimensional images (time and two-dimensional space images) were decomposed to wavelet time levels to extract the dominant particle concentration distribution using three-dimensional discrete wavelet multiresolution. As a result, the time-dominant particle distribution with a specific time frequency level can be visualized in cross-section. In detail, the high concentration of the particle spatial distribution at the dense flow front, which composes high time frequency levels 6 and 7, is centrally located above the stationary layer. The distribution image at the front is reasonable when compared with the particle velocity distribution by conventional laser Doppler velocimetry (LDV) that indicates the discharging particles toward the front air phase at the centerline.     

Linear polymers with sulfur in the main chain. IV. Synthesis of thermotropic liquid‐crystalline polythioesters based on 4,4′‐biphenyldithiol with excellent adhesive properties

A series of sulfur‐containing linear polythioesters were synthesized from 4,4′‐biphenyldithiol (BPT) and bifunctionally aliphatic acyl dichlorides (ACs) by means of polycondensation. Polycondensations of BPT with azelaoyl chloride or sebacoyl chloride chosen as a model reaction system were investigated in several solvents by solution polycondensation, to find an optimal solvent to achieve high molecular weight and quantitative yield. Thus, all the polythioesters from BPT and AC (methylene number of 3–10) were synthesized in chloroform and their structures were confirmed by ¹H‐NMR and Fourier transform infrared spectrophotometer. They were also evaluated by thermogravimetry and differential scanning calorimeter (DSC). Almost all of the BPT, polythioesters exhibited two distinct exothermic and endothermic peaks on first cooling and second heating in their DSC curves, respectively. Polarized microscope (PLM) observation clarified that the higher transition temperatures were isotropic temperatures (T_is). The odd–even effect between T_i and the methylene number was observed in these BPT polythioesters. Furthermore, almost all of the polythioesters showed thermotropic liquid‐crystalline behavior, as evidenced by a PLM observation. To know the effect of introduction of sulfur on adhesive properties of the polythioester/copper junction, a single lap shear test was carried out in comparison with corresponding 4,4′‐biphenyldiol (BPH) polyesters derived from BPH and ACs. It was clarified that the BPT polythioesters have greatly higher adhesive strengths in comparison with the BPH polyesters. POLYM. ENG. SCI., 47:262–269, 2007. © 2007 Society of Plastics Engineers.