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Cobalt-free oxide Sr0.7Y0.3CuO2+δ (SYCu) with one-dimensional structure has been investigated as potential cathode material for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. The crystal structure, chemical compatibility, thermal expansion and electrochemical performance were examined by X-ray diffraction technique, electrochemical workstation and thermal dilatometer. One-dimensional structure Sr1−xYxCuO2+δ and Sr2−xYxCuO3+δ phases appeared as the main parts after calcination above 900 °C. The copper based oxide SYCu showed a thermal expansion coefficient (TEC) about 11.1 × 10−6/°C at 25–800 °C, exhibiting good physical compatibility with samarium doped cerium (SDC) electrolyte. High electro-catalytic performance was obtained for SYCu cathode in a symmetrical cell with a polarization resistance (Rp) of 0.029 Ω cm2 and an overpotential of 4.9 mV at 100 mA/cm2 at 800 °C, showing great promising use as cathode materials for IT-SOFCs. In addition, the polarization resistance of SYCu cathode remain constant after operation at 800 °C for 100 h, showing excellent long-term stability at operation temperature.

A highly active Nafion-H catalyst is developed for vapour phase carbonylation of dimethoxymethane (DMM) to methyl methoxyacetate (MMAc) with a significant MMAc selectivity as high as 90%. The excellently catalytic performance is because of the unique structure and high acid strength of the Nafion-H catalyst.

Diamond-like carbon (DLC) coatings found many industrial applications in various fields, such as in aerospace, automotive bearing and electronic applications. DLC coatings performances are strictly correlated to their structure and composition which can be optimized controlling the substrate bias voltage (SBV). In this research, the corrosion and scratch resistance of DLC coatings applied on chromium molybdenum steel has been evaluated by electrochemical, microscopical and spectroscopical techniques. It has been observed that increasing the SBV leads to harder and more protective coatings, but decreases the resistance to delamination during scratch testing. Corrosion was always triggered at local defects of the Cr/C gradient interlayer, where the DLC layer was easily delaminated, exposing the chromium molybdenum steel substrate. The results of this study suggest that a better control of the Cr/C deposition parameters are necessary to further enhance corrosion resistance.

Alzheimer’s disease (AD) is a significant health issue for the elderly and becoming increasingly common as the global population ages. Although many efforts have been made to elucidate its pathology, there is still a lack of effective clinical anti-AD agents. Previous research has shown the neuroprotective properties of a combination of curcumin and vorinostat. In this study, nine other neuroprotective agents were investigated to examine whether a three-drug combination of curcumin, vorinostat, and a new drug is more advantageous than the previous two-drug combination in alleviating amyloid beta (Aβ)-induced nerve cell toxicity. Cell viability assay was performed to screen these agents, and further validation tests, including determination of cellular oxidative stress, apoptosis, and activity of the AKT/MDM2/p53 pathway, were performed. Among the nine candidate compounds, only silibinin at 1 µM reduced Aβ25–35-induced toxicity in PC12 cells. The neuroprotective effects of 1 µM silibinin in combination with 5 µM curcumin and 0.5 µM vorinostat (CVS) was shown in PC12 cells, in which it decreased apoptosis and oxidative stress marker levels that were increased by 20 µM Aβ25–35. Western blotting results showed that CVS pretreatment significantly increased the phosphorylation of AKT, BAD, and MDM2, which resulted in decreased intracellular expression of p53. Further, immunofluorescence results showed reduced p53 levels in the nuclei of PC12 cells following CVS pretreatment, indicating a reduction in the p53-mediated transcriptional activity associated with Aβ25–35 exposure. In conclusion, our findings suggested that pretreatment with CVS protected PC12 cells from Aβ25–35-induced toxicity through modulation of the AKT/MDM2/p53 pathway. Thus, CVS may present a new therapeutic option for treating AD.

Laser scanning ranging radar is an important tool for machines to perceive the surrounding environment and is widely used in the power, forestry, surveying and mapping industries. At present, the loading of oil and grain oil in our country generally adopts the way of manual loading. The loading arm is inserted into the tank of the tanker for refueling, and the loading operation is very frequent. In order to realize automatic control of grain and oil loading, radar is needed to assist the robot to locate the oil port of the tanker. In this paper, a 360-degree laser scanning ranging radar is used to collect characteristic data of oil hole of tanker for the first time in simulated environment. Cubic spline interpolation was used to smooth and correct the radar scan data. Based on the feature that the distance data of oil port will change rapidly, an edge feature recognition algorithm is proposed to screen and calculate the target point, and then convert it to cartesian coordinate point, which can be used as the positioning target of the robot unit of quantitative loading system. The experimental results show that the method can locate the center of the circle accurately and meet the requirement of feature recognition accuracy.

Raman spectroscopy and scanning electron microscopy, combined with the Vickers indentation method, were applied to analyze the fracture behavior of a thin (i.e., 1 μm in thickness) aluminum nitride (AlN) film deposited on a (001)Si substrate. A series of indentations were introduced in the AlN/Si system with applying gradually increasing loads, and the stress intensity factor, K R , stored at the tip of cracks propagated from the indentation corners was determined according to the shift of selected Raman bands from wurtzitic AlN in response to the crack-tip residual stress field. A steeply rising crack resistance curve was found in the AlN film, starting from an intrinsic toughness, K I0 = 0.6 MPa m 1/2 , for crack initiation up to K R ≅ 5 MPa m 1/2 (at a crack length of ~ 120 μm). Such rising R-curve behavior was attributed to the presence of a compressive residual stress field stored in the AlN film. The results obtained by Raman spectroscopy were consistently supported by direct crack opening displacement measurements in a scanning electron microscope.

In this article, we discuss a study of the influence of Nd(3+) and Yb(3+) dopants on the spectroscopic behavior of Y2O3 ceramic polycrystals, by using Raman and cathodoluminescence (CL) spectroscopy. Doping with Yb at 1 at % results in a blue shift of the Raman band but has no pronounced influence on the intrinsic emission of Y2O3, while doping with Nd shows a red shift of the Raman band and markedly enhances the oxygen vacancy related 380 nm CL band. Lattice distortion induced by the alien ion incorporation and variations of effective absorption coefficients by adding different dopants were assessed using Raman spectroscopy. Moreover, both CL and Raman spectroscopies were applied to examine the homogeneity and distribution of the dopants throughout the ceramic microstructure. Visualization of sample homogeneity was made available by hyperspectral imaging of the local intensity of CL bands, while spectral deconvolution was performed to retrieve local structural variations at grain boundaries. We also confirmed that the combination of Raman and CL spectroscopies leads to a reliable and useful methodology for the examination of dopants in yttria ceramic materials.

Background: Although inadequate intake of essential nutrient choline has been known to significantly increase cardiovascular risk, whether additional supplement of choline offering a protection against cardiac hypertrophy remain unstudied. Methods: The effects of choline supplements on pathological cardiac hypertrophic growth induced by transverse aorta constriction (TAC) for three weeks and cardiomyocyte hypertrophy in cultured cells induced by isoproterenol (ISO) 10 μM for 48 h stimulation were investigated. Western blot analysis and real-time PCR were used to determine the expression of ANP, BNP, β-MHC, miR-133a and Calcineurin. Results: Administration of 14 mg/kg choline to mice undergone TAC effectively attenuated the cardiac hypertrophic responses, as indicated by the reduced heart weight, left ventricular weight, ventricular thickness, and reduced expression of biomarker genes of cardiac hypertrophy. This anti-hypertrophic efficacy was reproduced in a cellular model of cardiomyocyte hypertrophy induced by isoproterenol in cultured neonatal cardiomyocytes. Our results further showed that choline rescued the aberrant downregulation of the muscle-specific microRNA miR-133a expression, a recently identified anti-hypertrophic factor, and restored the elevated calcineurin protein level, the key signaling molecule for the development of cardiac hypertrophy. These effects of choline were abolished by the M3 mAChR-specific antagonist 4-DAMP. Conclusion: Our study unraveled for the first time the cardioprotection of choline against cardiac hypertrophy, with correction of expression of miR-133a and calcineurin as a possible mechanism. Our findings suggest that choline supplement may be considered for adjunct anti-hypertrophy therapy.

Background/Aim: Epithelial Na+ channels (ENaC) play a crucial role in control of blood pressure by regulating renal Na+ reabsorption. Intracellular trafficking of ENaC is one of the key regulators of ENaC function, but a quantitative description of intracellular recycling of endogenously expressed ENaC is unavailable. We attempt here to provide a model for intracellular recycling after applying a protease inhibitor under hypotonic conditions. Methods: We simulated the ENaC-mediated Na+ transport in renal epithelial A6 cells measured as short-circuit currents using a four-state mathematical ENaC trafficking model. Results: We developed a four-state mathematical model of ENaC trafficking in the cytosol of renal epithelial cells that consists of: an insertion state of ENaC that can be trafficked to the apical membrane state (insertion rate); an apical membrane state of ENaC conducting Na+ across the apical membrane; a recycling state containing ENaC that are retrieved from the apical membrane state (endocytotic rate) and then to the insertion state (recycling rate) communicating with the apical membrane state or to a degradation state (degradation rate). We studied the effect of aprotinin (a protease inhibitor) blocking protease-induced cleavage of the extracellular loop of γ ENaC subunit on the rates of intracellular ENaC trafficking using the above-defined four-state mathematical model of ENaC trafficking and the recycling number relative to ENaC staying in the apical membrane. We found that aprotinin significantly reduced the insertion rate of ENaC to the apical membrane by 40%, the recycling rate of ENaC by 81%, the cumulative time of an individual ENaC staying in the apical membrane by 32%, the cumulative life-time after the first endocytosis of ENaC by 25%, and the cumulative Na+ absorption by 31%. The most interesting result of the present study is that cleavage of ENaC affects the intracellular ENaC trafficking rate and determines the residency time of ENaC, indicating that more active cleaved ENaCs stay longer at the apical membrane contributing to transcellular Na+ transport via an increase in recycling of ENaC to the apical membrane. Conclusion: The extracellular protease-induced cleavage of the extracellular loop of γ ENaC subunit increases transcellular epithelial Na+ transport by elevating the recycling rate of ENaC due to an increase in the recycling rate of ENaCs associated with increases in the insertion rate of ENaC.

In order for synthetic materials to be utilized as biomedical implants, their short- or intermediate-term biocompatibility must be validated. However, most biomaterials are not aptly assessed for their ability to successfully interface with the human milieu long-term. To be optimally effective, a biomaterial's state of biocompatibility and tissue integration should increase with time. Yet, the standard for selection of suitable materials today remains primarily bioinertness. In this regard, ceramics are popular because of their perceived stability within the human body. However, complete bioinertness for any material is virtually impossible; and acknowledging this fact is an important first step in the development of better biomedical devices. In this chapter, advanced spectroscopic techniques were employed to delve deep into the performance of several advanced bioceramics used in prosthetic joint implants. In contrast to the conventional notion that these materials are completely bioinert, it was found that surface chemical and structural changes readily occur upon contact with biological fluids. Furthermore, it was discovered that their “non-bioinertness”can be either beneficial or detrimental with respect to long-term reliability. In particular, the peculiar properties of silicon nitride, a non-oxide ceramic, make it a unique candidate for artificial joints and other biomedical devices. In contrast to oxide ceramics, the surface chemistry and mechanical behavior of silicon nitride appear to ideally lead to improved long-term performance.

Automatic detection of P-wave in an electrocardiogram(ECG) is a crucial task in diagnosis of the presence of arrhythmias. In this paper, we proposed an improved method based on distance transform. Distance transform is an efficient method for locating P-wave critical points, corresponding to subjective judgment of cardiologists. Auxiliary algorithms have also been introduced to improve the precision of distance transform, such as recognition of horizontal segments and rising or declining segment, then, feedback comes to narrow or widen the P wave searching area for the need of distance transform. The method is validated through a QT database. The experiments show that our method provides good results. The average error of P-wave onsets, ends and P-wave location is 8.5ms,10.4ms, and 7.6ms, and P wave boundary point detection accuracy is 98.9%, 97.8% respectively.

In this paper, we make a lot of research for the signal termination and crosstalk reducing methods, when the wearable device working in its particular working condition. Made an in-depth analysis of complex crosstalk signal analysis & match, in actually limited working condition. In this experiment, we made a Two-dimensional field analysis for the health monitor band's circuit board by using the PCB board-level signal integrity analysis tool—HyperLynx, We used a method which isolated the components of crosstalk noise, for the crosstalk to make analysis, measurement, and rectification. In the end, we proposed a appropriate optimization program adapt to the crosstalk noise optimize with the size limits of the wearable device.

The remarkable stoichiometric flexibility of hydroxyapatite (HAp) enables the formation of a variety of charged structural sites at the material’s surface which facilitates bone remodeling due to binding of biomolecule moieties in zwitterionic fashion. In this paper, we report for the first time that an optimized biomedical grade silicon nitride (Si3N4) demonstrated cell adhesion and improved osteoconductivity comparable to highly defective, non-stoichiometric natural hydroxyapatite. Si3N4’s zwitterionic-like behavior is a function of the dualism between positive and negative charged off-stoichiometric sites (i.e., N-vacancies versus silanols groups, respectively). Lattice defects at the biomaterial’s surface greatly promote interaction with positively- and negatively-charged functional groups in biomolecules and result in the biologically effective characteristics of silicon nitride. These findings are anticipated to be a starting point for further discoveries of therapeutic bone-graft substitute materials.

Diagnosis of sleep disorders in an expensive procedure that requires performing a sleep study, known as polysomnography(PSG), in a controlled environment. However, PSG still requires patients to use a cumbersome system with multiple recording channels that need to be precisely placed, which gives burden to testers greatly. This paper proposes a low-power sleep monitoring algorithm based on the wrist movement signal by studying several relatively mature algorithms of sleep. We combine with low-power hardware strategy, and enable power consumption of monitoring process to reduce by more than 50%. Besides, the monitoring results obtained in this paper are nearly superior to common sleep monitoring mechanism, such as proportional integral model, and accuracy also has risen greatly to a certain degree.

In this paper, an updated analytical model for the kinetics of the tetragonal to monoclinic (t→m) polymorphic transformation in ZTA composites for hip joints is proposed and discussed. The model builds upon the so-called Mehl-Avrami-Johnson (MAJ) description of transformation kinetics, which combines two overlapping processes: nucleation of monoclinic sites, and their successive growth. Dependencies on two specific factors are introduced in the model, namely the initial fraction of monoclinic polymorph as received from the manufacturer, and the presence of different types of transition-metal stains (e.g., Ti, CoCr, and Fe) on the ZTA surface. These two factors were studied because clear indications of their potential roles on the environmental stability of implantable ZTA components were found in previous phenomenological analyses of retrievals. Nucleation and growth of monoclinic domains are two key processes whose interplay decides the actual kinetics of the overall transformation process according to two main parameters: an apparent activation energy value function of time and temperature, and a nuclei growth exponent. These parameters were clearly altered by the presence of transition metal contamination, whose effect was incorporated into the model to explain exacerbations of surface degradation. In accordance with a general analytical description of transformation kinetics for isothermal or isochronal evolutions in terms of time and temperature, the modified model of the MAJ description assesses the effect of the initial monoclinic fraction. The updated model has been validated using systematic in vitro experiments, and appears to partly reconcile in vitro and in vivo data of t→m transformation discrepancies in ZTA hip components.

Understanding the intrinsic reason(s) for the enhanced tetragonal to monoclinic (t→m) polymorphic phase transformation observed on metal-stained surfaces of zirconia-toughened alumina (ZTA) requires detailed knowledge of off-stoichiometry reactions at the molecular scale. In this context, knowledge of the mechanism(s) for oxygen vacancy creation or annihilation at the material surface is a necessary prerequisite. The crucial aspect of the surface destabilization phenomenon, namely the availability of electrons and holes that allow for vacancy creation/annihilation, is elucidated in this paper. Metal-enhanced alterations of the oxygen sublattice in both Al2O3 and ZrO2 of the ZTA composite play a decisive role in accelerating the polymorphic transformation. According to spectroscopic evidences obtained through nanometer-scale analyses, enhanced annihilation of oxygen vacancies triggers polymorphic transformation in ZrO2 near the metal stain, while the overall Al2O3 lattice tends to dehydroxylate by forming oxygen vacancies. A mechanism for chemically driven "reactive metastability" is suggested, which results in accelerating the polymorphic transformation. The Al2O3 matrix is found to play a key-role in the ZrO2 transformation process, with unambiguous confirmation of oxygen and hydrogen transport at the material surface. It is postulated that this transport is mediated by migration of dissociated O and H elements at the surface of the stained transition metal as they become readily available by the thermally activated surrounding.

Exploitation of the toughening effect induced by polymorphic phase transformation of zirconia in zirconia-toughened alumina (ZTA) requires the composite being properly designed and carefully manufactured. A sound algorithm for predicting phase stability along with strict control over manufacturing steps are required in order to prevent possible in vivo surface degradation or implant fracture. This paper is the first in a series of three monographs, which aim at: (i) statistically comparing the in vitro/in vivo phenomenology of surface-metastability for currently marketed ZTA femoral heads; (ii) refining pre-existing theoretical models for predicting in vivo zirconia phase metastability via the use of accelerated in vitro ageing experiments; and, (iii) providing a rationale for the mechanism(s) involved with the observed in vivo surface metastability. This initial paper of a series of three, which specifically deals with item (i), shows discrepancies between the levels of polymorphic phase transformation detected in ZTA retrievals and in vitro predictions, and attempts a phenomenological analysis of the reasons behind such discrepancies. Moreover, marked inhomogeneities are also found among as-manufactured components through different years of production. The phenomenology of retrievals' data suggests key roles for both the presence of metallic stain and the initial value of monoclinic volume fraction.

Glioma is among the most common types of cancer of the central nervous system and is difficult to cure. Due to the lack of glioma-specific treatments, patients with glioma exhibit high mortality rates. MicroRNAs (miRNAs) participate in the pathogenesis of glioma, and upregulation of specific miRNAs promotes cell proliferation, whereas apoptosis‑inducing miRNAs are markedly downregulated in the context of glioma. Therefore, miRNAs may be important contributors to the pathogenesis of glioma. In the present study, nine miRNAs were investigated as miRNA‑miRNA pairs, and the measured cell viabilities were consistent with the results of synergy predictions. Extensive synergy occurred among upregulated miRNAs in U87 cells, whereas downregulated miRNAs rarely exhibited synergism. Treatment with an miRNA‑miRNA pair exhibiting strong synergy increased the inhibitory effects of these miRNAs on tumor cells, and the combined inhibitory effects were increased compared with the sum of the individual inhibitory effects of each miRNA. Using cell viability assays, TUNEL staining, and flow cytometry, the present study demonstrates that cotransfection with miR‑20a and miR‑21inhibitors resulted in the highest synergistic effect on the promotion of apoptosis in U87 cells. The results of the present study provide important insights into the potential use of miRNAs in the treatment of glioma.

We applied cathodoluminescence (CL) spectroscopy to evaluate the defect-induced luminescence within ZnO and Ga-doped ZnO (GZO) nanoparticles. The observed emissions from defect sites present in the GZO lattice exhibited a strong dependence on both dopant content and synthesis methods. The strong and broad defect-induced emissions and inhomogeneous population of intrinsic defects in nano-sized ZnO particles could effectively be suppressed by Ga doping, although large dopant amounts caused the generation of negatively-charged defects, VZn and Oi, with a subsequent increase of the luminescence. Upon deconvolution of the retrieved CL spectra into individual sub-bands, the physical origin of all the sub-bands could be clarified, and related to sample composition and synthesis protocol. This study lays the foundation of quantitative CL evaluation of defects to assess the quality of GZO optoelectronic devices.

To investigate the influence of simvastatin treatment on Toll-like receptor 4 (TLR4) in monocytes of peripheral blood in patients with sepsis and severe sepsis and its significance.A prospective randomized controlled trial was conducted. 106 patients with sepsis and 92 patients with severe sepsis admitted to Department of Critical Care Medicine of Henan Provincial People's Hospital from August 2013 to June 2015 were enrolled. These two groups of patients were randomized into conventional treatment group and simvastatin group. All patients received treatment according to the 2012 International Sepsis Treatment Guidelines, including anti-infection drugs, nutritional support, and palliative treatment, and the patients with severe sepsis were given early goal-directed therapy (EGDT). The patients in simvastatin group received simvastatin 40 mg daily orally for at least 15 days. The peripheral blood was collected and the monocytes were isolated at 1, 5, 10, 15 days after intensive care unit (ICU) admission. TLR4 expression on the surface of TLR4/CD14(+) double positive monocytes was determined by flow cytometry, and adverse reaction was observed during treatment.TLR4 expression on the surface of monocytes showed a tendency of decreasing with prolongation of simvastatin treatment in the simvastatin group in patients with sepsis (n = 59) or severe sepsis (n = 54). However, in patients with sepsis, TLR4 level was significantly decreased from 10 days in simvastatin group as compared with that of conventional therapy group (n = 47), and it was decreased up to 15 days [mean fluorescence intensity (MFI): 21 (19, 28) vs. 27 (25, 33) at 10 days, Z = 2.198, P = 0.021; 16 (15, 21) vs. 26 (23, 34) at 15 days, Z = 4.611, P = 0.002]. In patients with severe sepsis, there was no significant difference in TLR4 level at different time points between simvastatin group and conventional treatment group (n = 38) [MFI: 55 (52, 63) vs. 56 (48, 65) at 1 day, Z = 0.313, P = 0.692; 47 (42, 56) vs. 49 (41, 58) at 5 days, Z = 0.827, P = 0.533; 40 (35, 42) vs. 42 (37, 45) at 10 days, Z = 1.012, P = 0.301; 33 (30, 38) vs. 38 (35, 41) at 15 days, Z = 0.539, P = 0.571]. No adverse reaction related with simvastatin was found during treatment in patients with sepsis or severe sepsis.Statins could significantly down-regulate the TLR4 expression on peripheral blood monocytes in septic patients, while it showed no significant influence on TLR4 expression in patients with severe sepsis. A different effect of statins on TLR4 expression and the downstream inflammation process in sepsis and severe sepsis patients might partially explain the discrepancy in previous reports about the therapeutic effect of statins therapy in sepsis and severe sepsis patients.

MicroRNAs (miRNAs) are negative regulators of gene expression and protein abundance. Current evidence shows an association of miRNAs with acute kidney injury (AKI) leading to substantially increased morbidity and mortality. Here, we investigated whether miRNAs are inductive regulators responsible for the pathological development of AKI. Microarray analysis was used to detect temporal changes in global miRNA expression within 48 h after AKI in mice. Results indicated that global miRNA expression gradually increased over 24 h from ischemia reperfusion injury after 24 h, and then decreased from 24 h to 48 h. A similar trend was observed for the index of tubulointerstitial injury and the level of serum creatinine, and there was a significant correlation between the level of total miRNA expression and the level of serum creatinine (p< 0.05). This expression-phenotype correlation was validated by quantitative reverse transcription PCR on individual miRNAs, including miR-18a, -134, -182, -210 and -214. Increased global miRNA expression may lead to widespread translational repression and reduced cellular activity. Furthermore, significant inflammatory cytokine release and peritubular capillary loss were observed, suggesting that the initiation of systematic destruction programs was due to AKI. Our findings provide new understanding of the dominant role of miRNAs in promoting the pathological development of AKI.

The performance of the braking system has an important influence on the safe operation of the train. In this paper, the AMESim simulation software is used to simulate the pneumatic valve unit (PVU) for the direct electro-pneumatic braking system controlled by the microcomputer. And the correctness of the model is verified by the simulation of the service braking and the emergency braking. At the same time, the vehicle dynamics model is built in the MATLAB/Simulink environment, and the AMESim pneumatic valve model is combined with the simulation to verify the effectiveness of the anti-skid logic. The simulation results from the service braking and emergency braking can be drawn that the PVU for the direct electro-pneumatic braking system controlled by the microcomputer is consistent with the response of the real system, which verifies the correctness of the PVU model. It can be seen from the simulation results that the anti-skid control logic can achieve the control requirements, and can achieve the stability of the anti-skid effect in the event of a continuous sliding. The results of this study provide an effective model base for the design of the actual vehicle braking system and solutions to the fault.

Organisms of Gram-negative phylum bacteroidetes, Porphyromonas gingivalis, underwent lysis on polished surfaces of silicon nitride (Si3N4) bioceramics. The antibacterial activity of Si3N4 was mainly the result of chemically driven principles. The lytic activity, although not osmotic in nature, was related to the peculiar pH-dependent surface chemistry of Si3N4. A buffering effect via the formation of ammonium ions (NH4(+)) (and their modifications) was experimentally observed by pH microscopy. Lysis was confirmed by conventional fluorescence spectroscopy, and the bacteria's metabolism was traced with the aid of in situ Raman microprobe spectroscopy. This latter technique revealed the formation of peroxynitrite within the bacterium itself. Degradation of the bacteria's nucleic acid, drastic reduction in phenilalanine, and reduction of lipid concentration were observed due to short-term exposure (6 days) to Si3N4. Altering the surface chemistry of Si3N4 by either chemical etching or thermal oxidation influenced peroxynitrite formation and affected bacteria metabolism in different ways. Exploiting the peculiar surface chemistry of Si3N4 bioceramics could be helpful in counteracting Porphyromonas gingivalis in an alkaline pH environment.

The dielectric constant and electrical conductivity of a composite of two insulators, poly(1,1-difluoroethylene) (yellow) and K(2)CO(3) (white), increased dramatically near the percolation threshold f(c) (f=concentration of K(2)CO(3)). This intriguing phenomenon can be interpreted in terms of interface percolation caused by the formation of chemically activated interfaces.

A quantitative polarized Raman analysis of ferroelectric grain/domain orientation in LiSbO3 (LS-modified) (K0.5Na0.5)NbO3 (KNN) ceramics is presented, based on the analysis of the complex orientation dependence in space of their Raman-active modes. Complete sets of Raman tensor elements of Ag, and Eg phonon modes for orthorhombic/tetragonal structures of KNN have been determined. Through this spectroscopic algorithm, quantitative information could be extracted in terms of three Euler angles in space for KNN samples consisting of mixed phases, thus enabling quantitative visualization of the local distribution of grains/domains in the solid angle. As an application of the method, we quantitatively examined the unknown crystallographic grain orientation patterns on the surfaces of pure KNN and of KNN-0.05LS ceramics. These two samples were useful to clarify a polymorphic phase transition from the orthorhombic to the tetragonal phase taking place in the LS-modified KNN system. Thus, we demonstrated that polarized Raman spectroscopy is a valuable and efficient tool for nondestructive three-dimensional assessments of grain/domain orientation in ferroelectric materials with complex polymorphic structures. We believe that the data shown here represent a typical scenario encountered in grain/domain orientation assessments of piezoelectric perovskites. Copyright © 2012 John Wiley & Sons, Ltd.

Flavonoid extracts are widely used for preventing and treating ischemic heart disease. However, because many flavonoid extracts have been verified to inhibit CYP2D6 the main metabolic enzyme for the majority of antiarrhythmics and beta-blockers, co-administration of flavonoid extracts with these drugs may cause adverse herb-drug interaction in clinic. Here, we evaluated 43 common flavonoids on CYP2D6 inhibition in sillico and four commercial flavonoid extracts in vivo on the pharmacokinetics and pharmacodynamics of metoprolol in rats. Surprisingly, we found that the core skeletons of flavonoids instead of their substituents determine the extent of inhibiting CYP2D6 by a flavonoid extract. Isoflavones are less likely to inhibit CYP2D6, compared with other categories of flavonoids. Consistently, co-administration of soy extract that mainly contains isoflavones did not significantly increase plasma concentration of metoprolol and alter the systolic blood pressure of rats. Our results have implication in rationally selecting flavonoid extracts for therapeutic application.

Residual (elastic) stress profiles developed in self-mating alumina heads upon long-term exposure in the human body have been quantitatively determined by means of three different piezo-spectroscopic (PS) approaches available to the alumina lattice. The PS measurements, collected at exactly the same area of the sample, included fluorescence spectroscopy (fs), Raman spectroscopy (rs) (in-depth resolutions both in the order of the tens of μm), and cathodoluminescence spectroscopy (cs) (in-depth resolution down to the tens of nm). The lateral spatial resolution was in the order of the tens of μm, of the single μm, and of the hundredths of nm for fs and rs and cs, respectively. Owing to the precise knowledge of the response functions in space of the three probes, deconvoluted stress profiles could be obtained in zone of different wear severity. The profiles revealed high stress gradients along the material subsurface, “cleaned” from averaging effects related to the finite probe volume. The subsurface stress field in heavily worn zones entailed a surface layer under strong compression, an abrupt compressive-to-tensile transition up to a similar stress magnitude, and a deeper-lying region of tension which ultimately relaxed in the unstressed bulk. The opposite trend was observed in mildly worn zones of the femoral head, with moderate tensile stresses in the immediate surface and weak counterbalancing stresses of compressive nature along the subsurface. A wear mechanism for self-mating alumina hip surfaces was then drawn consistently with the newly available residual stress profiles.

The wear behavior of alumina femoral heads was examined at follow-up periods between 7.7 and 10.7 years. Four head retrievals of the same size (28 mm in diameter) were divided into two groups with different design characteristics. Systematically using scanning electron and atomic force microscopy procedures, wear characteristics could be classified on the entire heads according to five zones with increasing degrees of wear damage (Grade 1-5), in addition to one zone of stripe wear (Grade SW). The stripe wear zone showed quite different topographical features as compared to frictionally worn zones. Furthermore, hip implants designed with different clearances are shown to lead to different wear patterns on the femoral head surface, the smaller the clearance the wider the worn surface area. Cathodoluminescence piezo-spectroscopy provided information about the residual stress state in surfaces worn to different degrees and helped clarifying the wear mechanisms on the microscopic scale.

Ball-on-ring test is widely used to measure the biaxial strength of brittle materials by often making the approximation that the pressure applied by the ball in the central loading region is uniform. The purpose of the present study is to demonstrate the limits of such approximation by means of piezospectroscopy and to substantiate the spectroscopic findings with calculations based on finite element modeling (FEM). In addition, we shall discuss in some detail the validity of theoretical expressions previously developed by Kirstein and Woolley for radial and tangential bending stresses in the case of a uniformly distributed concentric load applied at the center of the disk loading region. A comparison is also offered between the experimentally retrieved radius of such region and those computed by theoretical models. Errors in estimating the radius of the central loading region, which have led in the past to controversial discussions, have been shown to play a minor role in the analysis of the overall stress field.

We use a single phase-only spatial light modulator and an iterative phase retrieval method to directly modulate the light at multiple planes inside the eye. By changing the focal length of the eye, images at different depth planes are sharply projected onto the retina, with which we mimic the accommodation of natural vision.

A theoretical Raman polarization analysis is proposed for the corundum structure of sapphire (α-Al2O3) and validation experiments conducted with the purpose of retrieving the full set of phonon deformation potentials (PDPs). From the theoretical side, the change in force constants under stress/strain has been expressed in matrix form, and close-form solutions were obtained for the eigenvalues that take into account the local dependence of oblique phonons on crystallographic orientation (i.e. uncoupling the effects of local crystal orientation and stress tensor from the shifts of Raman bands). From the experimental side, controlled (uniaxial) stress fields were applied to sapphire parallelepiped bars (along known crystallographic axes) while Raman spectra were systematically recorded along the bar thickness. An untextured alumina polycrystal with fine grain size was also investigated according to the same procedure. As a result of this set of experiments, PDPs for both A1g and Eg vibrational bands could be retrieved. Validation of PDP constants was obtained by measuring the steeply graded stress fields developed ahead of a surface crack propagated along an arbitrary crystallographic direction in the R-plane of the sapphire crystal. Copyright © 2011 John Wiley & Sons, Ltd.

We studied steep gradients of both chemical composition and residual stress in a Si-doped GaAs blocking layer of a laser diode by means of spectrally and spatially resolved cathodoluminescence (CL) spectroscopy. Using a low-energy electron beam as an excitation source for the CL emission, a spatial resolution in the sub-micron scale could be achieved. The knowledge of local doping concentration, local stress state, and their distribution on the nanometer scale is crucial in diode design since lasing characteristics and near-field width. Emphasis was placed in making quantitative the CL spectroscopic assessments in GaAs by means of a set of preliminary calibrations, regarding both probe size and material composition. These procedures enabled extracting from the CL spectra and quantitatively mapping values of both carrier concentration and residual stress in the diode device. The visualization of those parameters into highly spatially resolved maps (i.e., recorded with nanometer-scale resolution) required the implementation of a spectroscopic algorithm that was purposely built up in this study and preliminarily validated according to the shown sets of calibration procedures.

A spectroscopic method is shown to resolve the full set of components of the residual stress tensor, as it locally develops on the microstructural scale in polycrystalline alumina. A polarized/confocal Raman probe is employed. As a first step, the local crystallographic orientation of alumina grains is extracted from the angular dependence of the intensities of polarized Raman bands (i.e., upon in-plane rotation experiments) and expressed in terms of three Euler angles. Then, the stress tensor components for an unknown multiaxial stress state, expressed in their most general form through the Euler transformation matrix, are retrieved from solving the system of linear equations linking them to the observed spectral shifts of different (polarized) Raman bands. In order to clarify the sub-surface characteristics of the Raman probe and their effect of the assessment of the stress field stored among the alumina grains, both in-depth (defocusing) and in-plane (focal shift) analyses were first carried out to quantitatively determine the three-dimensional response of the Raman probe. Then, a computer-aided data restoration procedure was applied to the experimental data, which minimized the averaging effect of the laser probe and brought about the actual magnitude of the residual stress components. From the physics viewpoint, the most relevant feature of the newly proposed stress analysis is that stress tensor components could be individually determined without a direct knowledge of the secular equation pertaining the corundum crystal.

Barium titanate (BaTiO3), the most popular dielectric material for use in multilayer ceramic capacitors (MLCC), is often doped with rare earths ions to tailor its properties (e.g., Curie temperature, dielectric loss, and temperature coefficient of capacitance) and to control the mobility of its internal domain structure. The concurrent needs of device miniaturization and reliability improvement have challenged technologists to refine the design criteria regarding both material characteristics and device structure. However, further improvements cannot be easily achieved by merely empirical approaches and call for more systematic characterizations from the material physics viewpoint. This paper emphasizes the effect on the dielectric properties that arise from the formation of internal domain structures. A confocal/polarized Raman spectroscopic algorithm is developed and applied to quantitative characterizations of domain structures in BaTiO3 and applied to non-destructive diagnostics of an MLCC device.

The response to applied strain of EtO-sterilized and γ-irradiated polyethylene materials belonging to tibial inserts has been studied by polarized Raman spectroscopy. Initial calibrations on as-received samples from three different makers were employed to clarify the rearrangement of molecular chains under strain, expressed in terms of Euler angular displacements in space and orientation distribution functions. This body of information was then applied to a quantitative analysis of four tibial inserts (from the same three makers of the unused samples) retrieved after in vivo exposures ranging between 7 months and 5 years 8 months. The main results of the Raman analysis can be summarized as follows: (i) γ-irradiated samples experienced lower texturing on the molecular scale compared to EtO-sterilized samples, likely due to a higher strain recovery capability; and (ii) independent of sterilization method, the amount of plastic strain was mainly developed early after in vivo implantation, whereby out-of-plane molecules rotated under load onto planes parallel to the sample surface until saturation of angular displacements was reached.

It has been well documented that ion channels and intercellular gap junctional proteins participated in the pathophysiological processes of myocardial infarction (MI) which resulted in lethal arrhythmias and sudden cardiac death. miRNA expression is dynamically regulated during MI and altered miRNA expression can induce deregulation of ion channel genes at the post-transcriptional level. We conducted a rationally designed bioinformatics analysis combined with experimental approaches to screen key therapeutic members in the IUPHAR database and Wikipedia, a whole genome protein interaction network was established here and comprehensive topological assessment was applied to confirm the individual network status and to reflect their biological significance. Meanwhile, the number of validated and confidently predicted miRNAs regulating each gene encoding ion channel or gap junction protein was counted. miRNA analysis indicated that connexin 43 was under more intensive miRNA regulation compared with the other ion channel and gap junction proteins. Furthermore, the topological network analysis highlighted the important role of connexin 43 in MI and also identified the important biological roles of TRPV4, SCN5A, CACNA1C and TRPC6. The abnormal expression of TRPC6 was experimentally validated in 1 month MI model of rat, which implied its potential therapeutic target for MI. Our work suggested that network systems approach could gain valuable insight into the pathological mechanism of MI which has not been uncovered by previous experimental studies.

A confocal Raman investigation of Pb 1 − x La x Ti 1 − x /4 O 3 (PLT) thin films grown by RF magnetron sputtering on PbO x /Pt/Ti/SiO 2 /Si substrates with an intermediate LaSrCoO 3 (LSCO) layer was performed. The influence of the LaSrCoO 3 buffer layer was analyzed taking advantage of the observed Raman spectral band variation, which varied according to different manufacturing procedures. In the presence of a LSCO layer, the A1 (1TO) Raman mode, which was indicative of tetragonal distortion, was pronouncedly enhanced, and a slight deviation from the (0 0 1) plane of the film was observed from the angular dependence of the polarized Raman spectral intensity. Furthermore, the spectral band variation as well as the residual stress along the in-depth direction was measured in the film from cross-sectional spectral line scans. This latter measurement showed a relaxation of the lattice mismatch in the presence of LSCO and PbO layers.