▼ 

The MmNi_3.55Co_0.75Mn_0.4Al_0.3B_x hydrogen storage alloys with various boron contents of x=0, 0.05, 0.1, 0.2, 0.3 were prepared by a radio frequency levitation melting process. The electrochemical kinetics such as linear polarization, electrochemical impedance spectroscopy and anodic polarization were investigated. Such experimental results showed that the addition of boron could enhance the activation performance and the rate capability. With the increase of boron additive such a favorable effect became more pronounced.

▼ Novel UV curable waterborne polyurethane coatings (UVWPU) modified by melamine was prepared using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), α,α-dimethylol propionic acid (DMPA), hydroxyethyl acrylate (HEA) as main materials. Copolymer structure was verified using Fourier transform infrared spectroscopy (FT-IR). Performance of the coatings was evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and mechanical tests such as pencil hardness and resistance to water. The results showed that the modified UVWPU film had the good thermal resistance, water resistance and mechanical properties. The optimum melamine dosage was 4.70wt.%, the glass transition temperature (T_g) of the modified film increased by 20.4^oC and 5% weight-loss temperature (253^oC) increased by 105^oC. No change color, crinkle, desquamate, dehisce and frothy were found after the modified film dried at 130^oC for 2h.

▼ We describe an innovative method which can accurately determine the refractive index (RI) of individual microspheres by immersing the microspheres in a medium and analyzing their phase-contrast microscopic images. Compared with the current techniques for microsphere RI measurement, the method has several advantages: it is simple and easy and it cannot only measure the RI of each individual microsphere but also perform measurement simultaneously on all the microspheres in the same field of view. In measurement, microspheres are not required to be suspended in a specific liquid but in any medium with known RI which is appropriate for the microspheres or even just in atmosphere. By using microspheres with known RI as sensors, the method can also be used for rapid in situ measurement of the local RI of inhomogeneous media. In this paper, we describe the principle of the method and the experiments of using the method to measure the RI of individual microspheres. Its applications for sensing instantaneous RI/concentration/temperature variation in critical situations such as anywhere in mixing flows or living biological specimens are also presented.

▼ 

Plasma immersion ion implantation using a metal vacuum vapor arc (MEVVA) or cathodic arc source was used to modify the fluorine-based polymer, Teflon. Several transition metal ions such as Co, Ni, Cu were introduced into plasma and implanted into the Teflon surface. The chemical composition of the modified surface was determined by Rutherford backscattering spectrometry (RBS) and X-ray photoelectron spectroscopy (XPS). The metals were found to be distributed several nanometers from the surface and XPS results showed the formation of metallic carbides and fluorides on the surface. Contact angle measurement results demonstrate the favorable change in the wettability from being hydrophobic to hydrophilic. Our study shows that the increase of the surface energy is due to the change of the surface interaction properties after metal plasma implantation.

▼ 

In this paper, the micro-assembling tasks of the positioning system are discussed; an automatic micro-assembling system with vision-servo system is proposed to replace manual operations for assembling a microdroplet ejector; it consists of three-axis micro-stepping positioning stage and the image recognition system, which is composed of two CCD cameras with lenses and a designed image recognition code in C++ builder. For the image recognition system, circle outlines and a cross positioning mark are used to guide the micro-stepping stage to achieve assembling tasks. In the visual-servo system design, the automatic positioning with vision guidance is separated into two steps, which are the coarse positioning task with the global vision and the fine positioning task with the micro vision. For the coarse positioning task, the Sobel operator is used to find outline of positioning mark and then to calculate centre and radius by using the way of least-mean-square error algorithm. For the fine positioning task, the Hough transform is applied to find the straight line of the cross positioning mark. Finally, the micro-stepping positioning stage and image recognition system are integrated into an automatic vision-servo micro-assembling system by a designed code to achieve micro-assembling tasks automatically.

▼ 

One of the biggest advantages of plasma immersion ion implantation (PIII) is the capability of treating objects with irregular geometries without complex manipulation of target holder or beam rastering. The effectiveness of this approach depends on the uniformity of the incident ion dose. However, it is known that the lateral dose variation (non-uniformity) is less than optimal in some applications. Ion dose non-uniformity may lead to large variations in the biocompatibility for biomaterial implants. Therefore, ion dose uniformity is an issue frequently investigated since the inception of PIII. Unfortunately, perfect dose uniformity is usually difficult to achieve when treating samples with a complex shape. The problem arises from the non-uniformity of the plasma density and self-consistent expansion of the plasma sheath. Concave surfaces frequently receive a smaller ion dose compared to convex surfaces since ions in a limited volume are competing for more surfaces and are depleted more readily. An effective solution is to produce non-uniform plasmas. For example, at the concave site, a higher plasma density may be helpful to weaken the ion competition and delay the depletion time. Consequently, the ion dose uniformity can be improved. In the work described here, we conduct two-dimensional numerical simulation of PIII into a trench target with the novel notion of non-uniform plasma.

▼ 

Plasma immersion ion implantation (PIII) is attracting more attention as a surface processing technique. During PIII, the plasma is not frequently uniform due to hardware limitations, although numerical simulation of PIII processes is usually based on a uniform plasma environment. This may lead to incorrect and incomplete understanding of the PIII process and dynamics. In this work, numerical simulation is conducted using the particle-in-cell (PIC) model to consider the effects of non-uniform plasma in the vacuum chamber. The plasma source that is installed on top of the chamber produces down-stream plasmas with density diminishing from top to bottom. The simulation results demonstrate that the non-uniform plasma gives rise to an evidently different plasma sheath configuration and consequently different implantation dynamics compared to the uniform plasma case. The incident dose on the top surface is not uniform and the dose peak appears at a certain distance away from the target edge initially and gradually moves towards the central zone as time elapses. In comparison with uniform plasma implantation, the dose non-uniformity is more severe in the non-uniform plasma case although the plasma is uniform horizontally. This is due to the different focusing effects of the plasma sheath that depends on the plasma distribution.

▼ 

One of the biggest advantages of plasma immersion ion implantation (PIII) is the capability of treating objects with irregular geometries without complex manipulation of target holder or beam rastering. The effectiveness of this approach depends on the uniformity of the incident ion dose. However, it is known that the lateral dose variation (non-uniformity) is less than optimal in some applications. Ion dose non-uniformity may lead to large variations in the biocompatibility for biomaterial implants. Therefore, ion dose uniformity is an issue frequently investigated since the inception of PIII. Unfortunately, perfect dose uniformity is usually difficult to achieve when treating samples with a complex shape. The problem arises from the non-uniformity of the plasma density and self-consistent expansion of the plasma sheath. Concave surfaces frequently receive a smaller ion dose compared to convex surfaces since ions in a limited volume are competing for more surfaces and are depleted more readily. An effective solution is to produce non-uniform plasmas. For example, at the concave site, a higher plasma density may be helpful to weaken the ion competition and delay the depletion time. Consequently, the ion dose uniformity can be improved. In the work described here, we conduct two-dimensional numerical simulation of PIII into a trench target with the novel notion of non-uniform plasma.

▼ 

Plasma immersion ion implantation (PIII) is attracting more attention as a surface processing technique. During PIII, the plasma is not frequently uniform due to hardware limitations, although numerical simulation of PIII processes is usually based on a uniform plasma environment. This may lead to incorrect and incomplete understanding of the PIII process and dynamics. In this work, numerical simulation is conducted using the particle-in-cell (PIC) model to consider the effects of non-uniform plasma in the vacuum chamber. The plasma source that is installed on top of the chamber produces down-stream plasmas with density diminishing from top to bottom. The simulation results demonstrate that the non-uniform plasma gives rise to an evidently different plasma sheath configuration and consequently different implantation dynamics compared to the uniform plasma case. The incident dose on the top surface is not uniform and the dose peak appears at a certain distance away from the target edge initially and gradually moves towards the central zone as time elapses. In comparison with uniform plasma implantation, the dose non-uniformity is more severe in the non-uniform plasma case although the plasma is uniform horizontally. This is due to the different focusing effects of the plasma sheath that depends on the plasma distribution.

▼ We developed a technique using quantum dot (QD) as a sensor for quantitative visualization of the surface charge on biological cells with nano-scale resolution. The QD system was designed and synthesized using amino modified CdSe/ZnS nanoparticles. In a specially designed buffer solution, they are positively charged and can homogeneously disperse in the aqueous environment to label all the negative charges on the surfaces of living cells. Using a wide-field optical sectioning microscopy to achieve 2D/3D imaging of the QD-labeled cells, we determined the charge densities of different kinds of cells from normal to mutant ones. The information about the surface charge distribution is significant in evaluating the structure, function, biological behavior and even malignant transformation of cells.

▼ 

Polymer surfaces typically have low surface tension and high chemical inertness and so they usually have poor wetting and adhesion properties. The surface properties can be altered by modifying the molecular structure using plasma immersion ion implantation (PIII). In this work, Nylon-6 was treated using oxygen/nitrogen PIII. The observed improvement in the wettability is due to the oxygenated and nitrogen (amine) functional groups created on the polymer surface by the plasma treatment. X-ray photoelectron spectroscopy (XPS) results show that nitrogen and oxygen plasma implantation result in C–C bond breaking to form the imine and amine groups as well as alcohol and/or carbonyl groups on the surface. The water contact angle results reveal that the surface wetting properties depend on the functional groups, which can be adjusted by the ratio of oxygen–nitrogen mixtures.

▼ Butyrate has been shown to display anti-cancer activity through the induction of apoptosis in various cancer cells. However, the underlying mechanism involved in butyrate-induced apoptosis is still not fully understood. Here, we investigated the cytotoxicity mechanism of butyrate in human colon cancer RKO cells. The results showed that butyrate induced a strong growth inhibitory effect against RKO cells. Butyrate also effectively induced apoptosis in RKO cells, which was characterized by DNA fragmentation, nuclear staining of DAPI, and the activation of caspase-9 and caspase-3. The expression of anti-apoptotic protein Bcl-2 decreased, whereas the apoptotic protein Bax increased in a dose-dependent manner during butyrate-induced apoptosis. Moreover, treatment of RKO cells with butyrate induced a sustained activation of the phosphorylation of c-jun N-terminal kinase (JNK) in a dose- and time-dependent manner, and the pharmacological inhibition of JNK MAPK by SP600125 significantly abolished the butyrate-induced apoptosis in RKO cells. These results suggest that butyrate acts on RKO cells via the JNK but not the p38 pathway. Butyrate triggered the caspase apoptotic pathway, indicated by an enhanced Bax-to-Bcl-2 expression ratio and caspase cascade reaction, which was blocked by SP600125. Taken together, our data indicate that butyrate induces apoptosis through JNK MAPK activation in colon cancer RKO cells.

▼ 

Biodegradable polymer/bioceramic composites scaffold can overcome the limitation of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. To better mimic the mineral component and the microstructure of natural bone, novel nano-hydroxyapatite (NHA)/polymer composite scaffolds with high porosity and well-controlled pore architectures as well as high exposure of the bioactive ceramics to the scaffold surface is developed for efficient bone tissue engineering. In this article, regular and highly interconnected porous poly(lactide-co-glycolide) (PLGA)/NHA scaffolds are fabricated by thermally induced phase separation technique. The effects of solvent composition, polymer concentration, coarsening temperature, and coarsening time as well as NHA content on the micro-morphology, mechanical properties of the PLGA/NHA scaffolds are investigated. The results show that pore size of the PLGA/NHA scaffolds decrease with the increase of PLGA concentration and NHA content. The introduction of NHA greatly increase the mechanical properties and water absorption ability which greatly increase with the increase of NHA content. Mesenchymal stem cells are seeded and cultured in three-dimensional (3D) PLGA/NHA scaffolds to fabricate in vitro tissue engineering bone, which is investigated by adhesion rate, cell morphology, cell numbers, and alkaline phosphatase assay. The results display that the PLGA/NHA scaffolds exhibit significantly higher cell growth, alkaline phosphatase activity than PLGA scaffolds, especially the PLGA/NHA scaffolds with 10 wt.% NHA. The results suggest that the newly developed PLGA/NHA composite scaffolds may serve as an excellent 3D substrate for cell attachment and migration in bone tissue engineering.

▼ 

The objective of this study was to evaluate the effects of glycerol supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers (450±12 kg) were used in a replicated 4×4 Latin Square arrangement of treatments with experimental period of 21 days long. The treatments were: control (without glycerol), LG, MG and HG with 100, 200 and 300 g glycerol per head per day, respectively. Diet consisted of 60% corn stover and 40% concentrate (dry matter [DM] basis). Dry matter intake (averaged 9 kg/day) was restricted to a maximum of 90% of ad libitum intake. Ruminal pH (range of 6.58 to 6.23) was linearly (P<0.05) decreased, whereas total VFA concentration (range of 93.40 to 99.61 mM) was linearly (P<0.03) increased with increasing glycerol supplementation. Ratio of acetate to propionate decreased linearly (P<0.02) from 4.56 to 3.64 as glycerol supplementation increased due to the increased in propionate production. In situ ruminal NDF degradation of corn stover was improved but the CP degradability of concentrate mix was decreased with increasing doses of glycerol. Urinary excretion of purine derivatives was quadratically (P<0.02) changed with altering glycerol supplementation (65.0, 65.7, 71.1 and 67.2 mmol/d for control, LG, MG and HG, respectively). Similarly, digestibilities of OM, NDF and CP in the total tract were also linearly increased with increasing glycerol. The results indicate that glycerol supplementation potentially improves rumen fermentation with increased propionate production and feed digestibility in the total digestive tract of beef cattle. It suggests that feeding glycerol stimulates the ruminal microorganisms or digestive enzymes in a dose-dependent manner. Under the current experimental conditions, the optimum glycerol dose was about 200 g glycerol per head per day.

▼ 

The objective of this study was to evaluate the effects of malic acid (MA) on feed intake, milk yield and composition, blood metabolites and energy balance in early lactation Holstein dairy cows from 1 to 63 day in milk (DIM). Twenty-eight multiparous Holstein dairy cows, blocked by lactation number, previous 305-d mature equivalent milk production, and expected calving date, were arranged into four groups in a randomized block design. Treatments were: control (without MA), LMA, MMA and HMA with 70, 140 and 210 g malic acid per cow per day, respectively. The supplement of food grade MA (99.8% of MA) was hand-mixed into the top one-third of the daily ration. Cows were fed ad libitum a total mixed ration consisting of equal proportion of forage and concentrate. Milk yield increased (P=0.04), but feed intake and milk components were not affected (P>0.05) by MA supplementation. The energy balance, expressed as the difference between energy input and output, tended to be higher (P=0.08) for MA supplemented cows during the 63-DIM period MA and supplemented cows showed a trend (P=0.07) toward less loss of BW during the 63-day period, especially during the first 21-day of lactation. Concentrations of plasma glucose and serum insulin were higher for cows fed LMA, MMA, and HMA relative to control and linearly (P<0.01) increased with increasing MA supplementation. Concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA) and urine ketones were lower for MA-supplemented cows at 7, 14 and 21 DIM of lactation and linearly (P<0.01) decreased with increasing MA supplementation. Although feed intake was not affected, milk yield increased, MA-supplemented cows experienced higher concentrations of plasma glucose and serum insulin, lower concentrations of plasma BHBA and NEFA, and lower concentrations of urine ketones, suggesting that nutrient digestibilities and energy availability may have been improved.

▼ 

The objective was to evaluate the effects of selenium-yeast (SY) supplementation on rumen fermentation, lactation performance and feed digestibilities in dairy cows. Twenty-eight multiparous (2.5±0.3 parity) Holstein dairy cows, averaging 625±18.2kg of BW, 63±3.0days in milk and average daily milk production of 26.2±0.5kg/cow were used in a replicated 4×4 Latin square experiment. Treatments were: control, LSY, MSY and HSY with 0, 150, 300 and 450mg selenium yeast (Sel-Plex®, 1g/kg selenium, produced from Saccharomyces cerevisiae CNCM I-3060) per kg of diet dry matter (DM), respectively. Experimental periods were 45days with 30days of adaptation and 15days of sampling. Ruminal pH was lower for MSY than for control and was linearly (P=0.03) decreased, whereas total VFA concentration was linearly and quadratically (P≤0.01) increased with increasing SY supplementation, with the least for control, followed by LSY and HSY, and the highest for MSY. Ratio of acetate to propionate was lower for LSY, MSY and HSY than for control, and was linearly and quadratically (P≤0.01) decreased as SY supplementation increased due to an increase in molar proportion of propionate. Ruminal ammonia N content was lower (P≤0.01) for MSY and HSY than for control and was linearly decreased (P≤0.01) with increasing SY supplementation. Dry matter intake, proportions and yields of milk fat, protein and lactose were not affected (P>0.05). Milk yields and 4% FCM were higher (P≤0.05) for LSY and MSY than for HSY and control. Milk selenium content was linearly and quadratically (P≤0.01) increased as increasing SY supplementation, with the least for control, followed by LSY and MSY, and the highest for HSY. Digestibilities of DM, organic matter (OM), crude protein (CP), ether extract (EE), aNDF and ADF in the total tract were higher (P<0.01) for LSY and MSY than for control and HSY. The results indicate that supplementation of diet with SY improved rumen fermentation, milk yields, milk selenium, and feed digestion. It was suggested that the SY stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum selenium-yeast dose was about 300mg per kg diet DM.

▼ 

The objective of this study was to evaluate the effects of LaCl₃ supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers (420±20kg) were used in a replicated 4×4 Latin square experiment. The treatments were control (without LaCl₃); La-low; La-medium and La-high with 450, 900 and 1800mg LaCl₃ per steer per day, respectively. Diet consisted of 600g/kg corn stover and 400g/kg concentrate (dry matter [DM] basis). Dry matter intake (averaged 9kg/day) was restricted to a maximum of 90% of ad libitum intake. Ruminal pH (range of 6.59–6.42) was quadratically (P<0.04) changed, whereas total volatile fatty acids (VFA) concentration (range of 74.16–88.61mM) was linearly (P<0.01) and quadratically (P<0.01) increased with increasing La supplementation. Ratio of acetate to propionate decreased linearly (P<0.01) from 3.28 to 1.79 as La supplementation increased due to the increased in propionate production. In situ ruminal neutral detergent fibre (aNDF) degradation of corn stover was improved but the crude protein (CP) degradability of soybean meal was decreased with increasing La supplementation. Urinary excretion of purine derivatives was quadratically (P<0.01) changed with altering La supplementation (75.5, 81.0, 82.4 and 70.6mmol/day for control, low-, medium- and high-LaCl₃ supplementation, respectively). Similarly, digestibilities of organic matter, aNDF and CP in the total tract were also linearly and quadratically increased with increasing La supplementation. The present results indicate that supplementation of diet with LaCl₃ improved rumen fermentation and feed digestion in beef cattle. It was suggested that the La stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum La dose was about 900mg LaCl₃ per steer per day.

▼ 

The objective was to evaluate effects of glycerol supplementation on feed intake, milk yield and milk composition, blood metabolites and energy balance in Holstein dairy cows from 4 to 63 days in milk (DIM). Thirty-six multiparous cows, blocked by lactation number, previous 305 day mature equivalent milk production and expected calving date, were arranged into four groups in a randomized block design. Treatments were: control (without glycerol), glycerol-low (LG), glycerol-medium (MG) and glycerol-high (HG) with 100, 200 and 300g glycerol per cow per day, respectively. The supplement of food grade glycerol (0.998g/g glycerol) was hand-mixed into the top one-third of the daily ratio. Cows were fed ad libitum a total mixed ratio consisting of equal proportions of forage and concentrate. Feed intake, milk yield and its components were not affected by glycerol supplementation. The energy balance, expressed as differences between energy input NE_I and output (NE_M+NE_L) in MJ per cow per day, was higher (P<0.04) as glycerol supplementation level increased, especially during the first 17 and last 20 days of the 63 day period. Glycerol-supplemented cows tended (P<0.06) toward less loss of BW, especially first 17 and last 20 days of the 63 day period. Concentrations of glucose in plasma were higher for cows fed glycerol relative to control (54.1mg/dL versus 58.1mg/dL, respectively) and linearly increased (P<0.01) with increasing glycerol supplementation level. Concentrations of non-esterified fatty acids, beta-hydroxybutyrate and urine ketones were lower for glycerol-supplemented cows at 7, 14 and 21 days of lactation and linearly (P<0.01) decreased with increasing glycerol supplementation. Although milk yield and feed intake were not affected, glycerol-supplemented cows has a more positive energy status (higher concentrations of plasma glucose, lower concentrations of plasma beta-hydroxybutyrate, lower concentrations of urine ketones), suggesting that net energy availability may have been increased.

▼ The objective of this study was to evaluate effects of isobutyrate supplementation on rumen fermentation, lactation performance and plasma characteristics of dairy cows. Twenty multiparous second filial generation (F2) cows of a cross between Chinese Jinnan Yellow and Holstein cows at 148+/-4.5 days in milk and 22.3+/-0.81kg milk production were used in a replicated 4x4 Latin square experiment. The treatments were: control (without isobutyrate), low (LIB), medium (MIB) and high (HIB) isobutyrate supplementation of 20, 40 and 60g per cow per day, respectively. Experimental periods were 30 days with 15d of adaptation and 15d of data collection. Dry matter (DM) intake was not affected by increasing isobutyrate supplementation, but milk yields were highest for the 40g/d isobutyrate supplementation level, where proportion of milk fat, true protein and lactose were minimized. Ruminal pH (6.38-6.24) and ammonia N (13.8-11.1mg/100ml) were linearly (P<0.01) decreased, whereas total VFA concentration (124-131mM) increased at a decreasing rate with increasing isobutyrate supplementation. The ratio of acetate to propionate increased linearly (P<0.01) from 2.77 to 4.43 as isobutyrate supplementation increased due to the increase in acetate production and decrease in propionate production. Digestibilities of OM in the total tract increased linearly (P<0.01) as isobutyrate supplementation increased, digestibilities of DM and EE were highest for the 40g/d isobutyrate supplementation level, digestibilities of CP, aNDF and ADF increased at a decreasing rate with increasing isobutyrate supplementation. Plasma concentrations of glucose and growth hormone linearly (P<0.03) increased, whereas concentrations of non-esterified fatty acids linearly (P<0.01) decreased. Results indicate that supplementation of this diet with isobutyrate changed the rumen fermentation pattern towards acetate production, improved digestion and modified plasma concentrations of glucose and growth hormone. This suggests that isobutyrate stimulated digestive microorganisms or enzymes in a dose-dependent manner with the optimum isobutyrate dose at about 40g per cow per day in terms of improved digestion.

▼ 

The thermal entanglement in a three-qubit Heisenberg XXX spin chains with a impurity site is investigated under an external magnetic field. For a fixed Formula Not Shown or Formula Not Shown , we discussed the effect of the impurity parameter Formula Not Shown and the magnetic field B to the concurrence. The calculation results reveal that the impurity parameter Formula Not Shown and the magnetic field B can significantly effect the pair entanglement between the spin lattices with a different way on the case of anti-ferromagnetic ( Formula Not Shown ) or ferromagnetic ( Formula Not Shown ).

▼ We investigate the temporal evolution of entanglement of three spin qubits coupled to an XY spin-chain with Dzyaloshinsky-Moriya (DM) interaction environment. For an initial state with W, we find that the DM interaction can enhance slightly the decay of entanglement both in the weak coupling region and strong coupling one. However, for an initial state with GHZ, the decay of entanglement is very sensitive to the DM interaction in the strong coupling region.

▼ 

The ground state and thermal entanglement of a Heisenberg spin chain in the presence of the multiple coupling interaction (type of XZX+YZY and type of XZY−YZX) is investigated. It is found that the role of the type of XZY−YZX interaction to the entanglement is identical to the Dzyaloshinsky–Moriya interaction. For a XZX+YZY type three-site interaction, the results show that this interaction can excite and enhance the entanglement even at the higher temperature.

▼ 

We investigate the quantum critical behavior in the XY spin chain with multiple interaction by means of geometric phase (GP). Near the critical point, the key ingredients of the quantum criticality are investigated carefully, and the results show that the GP is reliable to characterize the quantum critical behavior in such system and the multiple interaction can induce the redistribution of the criticality region.

▼ 

Aluminum titanate precursor powders, containing 2.5wt.% MgO additive, were prepared by two powder processing methods, the hydrolysis of alkoxides and coprecipitation of inorganic salts. The hydrolysis-derived precursor powder showed a higher chemical homogeneity than the coprecipitated-derived precursor powder. Dilatometric analysis, accomplished with XRD and microscopy, was a very good method to study both phase transformation and sintering processes. Different phase transformation paths of TiO₂ and Al₂O₃ were observed in the two powders. The formation of aluminum titanate solid solution began at ∼1220°C in both, but in the hydrolysis-derived powder compact the aluminum titanate grains grew faster, leading to incomplete reaction and a non-uniform microstructure of large grains with small residual inclusions.

▼ SLC5A8 (Solute carrier family 5, member 8), proposed to be a potential tumor suppressor gene, is down-regulated by epigenetic changes in some colorectal cancer cells, and ectopic expression of SLC5A8 in SLC5A8-deficient colon cancer cell lines leads to suppression of the colony-forming ability of these cells. Activin A, a member of the transforming growth factor-β (TGF-β) superfamily, has been shown to inhibit the proliferation of a variety of tumor (and normal) human cell types. However, the mechanism(s) by which activin A exerts its inhibitory effects are not yet understood. In this study, we showed that activin A up-regulated SLC5A8 expression in colorectal cancer RKO cells and human embryonic kidney (HEK) 293T cells. To elucidate the underlying mechanism involved in this process, we investigated the activation of the Smad signaling pathway, and analyzed the effects of dominant negative Smad3 and Smad2 proteins on activin A-induced SLC5A8 expression. The results indicated that activin A-induced SLC5A8 expression was dependent on activation of Smad3. Further analysis showed that activin A induced SLC5A8 expression via transcriptional activation. Deletion analysis indicated that the CAGA elements located within the -273/-222 region of the human SLC5A8 promoter were responsive to activin A. Taken together, our results strongly suggest that activin A up-regulates SLC5A8 expression through the Smad signaling pathway, which also partially explains the inhibitory effects of activin A in RKO cells.

▼ Caveolae, the major source of caveolin-1 protein, are specialized invaginated microdomains of the plasma membrane that act as organizing centers for signaling molecules in the immune system. In the present study, we report the cloning and characterization of caveolin-1 (mCav-1) from mandarin fish (Siniperca chuatsi) and study on the roles of mCav-1 in the fish Jak-Stat signaling pathway and in virus infection. The cDNA sequence of mCav-1 was 707bp in size, encoding a protein of 181 amino acids, which was different from the mammalian protein (178 amino acids). The deduced amino acid sequence of mCav-1 shared similar architecture with vertebrate caveolin-1 proteins, but mCav-1 lacked a phosphorylation site (y14). The major subcellular location of mCav-1 was in the caveolae, where the protein appeared to have major functions. Real-time PCR revealed that the expression of the mandarin fish Mx, IRF-1, SOCS1, and SOCS3 genes involved in the poly(I:C)-induced Jak-Stat signaling pathway was impaired by the mCav-1 scaffolding domain peptide (mSDP). In mandarin fish fry (MFF-1) cells, the protein levels of mCav-1 were markedly up-regulated at 12 and 24h post-infection with ISKNV (infectious spleen and kidney necrosis virus). In addition, ISKNV entry into MFF-1 cells was significantly inhibited by mSDP, and the inhibition was dose-dependent. Thus, ISKNV infection was apparently associated with mCav-1 protein and may utilize the caveolae-related endocytosis pathway. The findings reported here further our understanding of the function of caveolin-1 in the complex signal transduction network in fish immune systems and in the cellular entry mechanism of iridoviruses.