Characterization of nanoscale mechanical heterogeneity in a metallic glass by dynamic force microscopy

We report nanoscale mechanical heterogeneity of a metallic glass characterized by dynamic force microscopy. Apparent energy dissipation with a variation of ~12%, originating from nonuniform distribution of local viscoelasticity, was observed. The correlation length of the heterogeneity was measured to be ~2.5 nm, consistent with the dimension of shear transformation zones for plastic flow. This study provides the first experimental evidence on the nanoscale viscoelastic heterogeneity in metallic glasses and may fill the gap between atomic models and macroscopic glass properties.

Diode-pumped passively mode-locked Nd:YVO4 laser at 1342 nm with periodically poled LiNbO3

In this Letter, we demonstrate a nonlinear-mirror (NLM) mode-locked diode-pumped solid-state Nd:YVO4 laser operating at 1342 nm, in which the NLM comprises a periodically poled LiNbO3 crystal and a dichroic mirror. The self-starting threshold for cw mode locking is 1.5 W, which is significantly lower than that of saturable absorber mode locking. An average power of 1.52 W at 1342 nm is obtained under diode pump power of 10 W at 808 nm, with the slope efficiency being up to 16.8%. The pulse width and the repetition rate of the mode-locked laser output are about 9.5 ps and 101 MHz, respectively.

Cavity phase matching via an optical parametric oscillator consisting of a dielectric nonlinear crystal sheet

We experimentally demonstrate cavity phase matching for the first time using a sheet optical parametric oscillator which is made of an x-cut KTiOPO(4) crystal sheet. This microcavity presents 220 kW peak power capability for near-frequency-degenerate parametric outputs with up to 23.8% slope efficiency. It also features unique spectral characteristics such as single-longitudinal-mode and narrow linewidth. These attractive properties predict broad applications of such a mini-device, such as terahertz generation, photonic integration, spectroscopy, and quantum information, etc.

rSj16, a recombinant protein of Schistosoma japonicum-derived molecule, reduces severity of the complete Freund's adjuvant-induced adjuvant arthritis in rats' model

Sj16, a 16-kDa protein produced by Schistosoma japonicum, has been demonstrated to have anti-inflammatory effect. However, the possible mechanism of these phenomena has not been discovered. Here, we tried to touch it with arthritis rats' model induced by injection of complete Freund's adjuvant (CFA). A set of pathogenic characters were observed in CFA-treated rat, including local and systematic read-out, which showed the model successfully set up. After administration of rSj16 (recombinant Sj16) in vivo, paw swelling reduced significantly and in a dose-dependent manner, the level of TNF-α, IL-1β and NO decreased and IL-10 in the serum increased. In vitro, rSj16 reversed the augmented surface expression of CD80, CD86, CD54 and OX6 induced by lipopolysaccharide (LPS) in bone marrow-derived DCs (BMDCs), whereas endocytotic capacity of rSj16-treated dendritic cell (DC) was profoundly increased. IL-12p70 released from rSj16-treated BMDC was decreased but IL-10 increased. Further, following incubation with rSj16 primed BMDCs, the sensitized T cells exhibited increased production of anti-inflammatory IL-10 and IL-4 and decreased production of IL-12p70 and IFN-γ. Collectively, these results implied that rSj16 alleviated CFA-induced arthritis, and the possible mechanisms may be its interruption of maturation and function of DCs. rSj16 could be a potential therapeutic agent against rheumatoid arthritis.

First Report of Cucurbit chlorotic yellows virus in Cucumber, Melon, and Watermelon in China

Systemic foliar chlorosis of melon, watermelon, and cucumber plants grown in plastichouses was first observed in Shanghai, China in 2008. By the end of October 2009, this symptom had become prevalent across 13,000 ha of plastichouses in Shanghai, Ningbo in Zhejiang Province, and Shouguang in Shandong Province. By mid-October, disease incidence ranged from 50 to 100% and losses were estimated between 10 and 20% across 100 plastichouses. Initial disease symptoms were chlorosis beginning at the base and middle portion of the older leaves followed by development of chlorotic spots on the lamina. Within 4 to 5 days, the entire leaf lamina was bright yellow and the veins remained green. The whitefly, Bemisia tabaci, was frequently observed colonizing plants in all plastichouses included in this study. Leaf samples were collected from six symptomatic cucumber, melon, and watermelon plants from individual plastichouses in Shanghai, Ningbo, and Shouguang. A pair of degenerate primers, F-5'-GGN TTA GAN TTC GGN ACN AC-3' and R-5'-TCA AAN GTN CCN CCN CCN AA-3', that were specific for the genera Crinivirus and Closterovirus, family Closteroviridae (2) were used to amplify a 636-bp fragment of the viral heat shock protein 70 gene (Hsp70). A PCR product of the expected size was amplified from RNA extracted with TaKaRa RNAiso Reagent (TaKaRa, Dalian, China) from symptomatic leaf samples: 3 of 3 melon, 2 of 2 watermelon, and 1 of 1 cucumber, and from 5 of 5 Bemisia tabaci adults collected from plants in five plastichouses in Shanghai, Ningbo, and Shouguang. No PCR product was obtained from RNA extracted from cucumber leaves grown in a virus-free facility at the Fruit Research Institute, Zhengzhou. PCR products were sequenced from representative plants samples and the sequences were submitted to GenBank (Nos. GU721105 to GU721107, GU72118 to GU721110, and GU721111. The six Hsp70 sequences shared 99.8 to 100% identity with Cucurbit chlorotic yellows virus (CCYV) (GenBank No. AB523789) from Japan. Using the complete CCYV sequence (1), PCR primers were designed to amplify the complete CCYV coat protein (Cp): Cp F-5'-CGCAATCAATAAGGCGGCGACC-3' and Cp R-5'-ACTACAACCTCCCGGTGCCAACT-3' (804 bp), minor Cp (Cpm): Cpm-F-5'-TGATGAANTGCCANGCTNTGAAA-3' and Cpm-R5'-ACAANTGATTCACATTNACAAT-3' (1,632 bp); and Hsp70: Hsp F-5'-TGCAACCGATGTCAGGTTCAGCG-3' with Hsp R-5'-TGGATAATTGGTCACGACCTCCAGT-3' (1,947 bp). One PCR amplicon was obtained for each target gene using RNA extracted from a cucumber collected in Ningbo. Three of the PCR amplicons were cloned and the DNA sequence was determined. A representative sequence for each gene was deposited in GenBank as: cp (HM581658), cpm (HM581657), and hsp70 (HM581659). The cp, cpm, and hsp70 sequences shared 99.7, 99.9, and 99.9% nt identity with the respective genes of CCYV (AB523789), whereas they shared only 62.5, 49.9, and 69.6% identity with the respective gene sequences for Cucurbit yellow stunting disorder virus (CYSDV; NC004810), suggesting the two viruses are divergent crinivirus species. Although this virus was first reported to infect cucurbits in Japan in 2009 (1), to our knowledge, this is the first report of CCYV in China. Eradication and management efforts are therefore paramount to reducing the spread of the disease. References: (1) M. Okuda et al. Phytopathology 100:560, 2010. (2) T. Tian et al. Phytopathology 86:1167, 1996.

Chiral charge-density waves

We discovered the chirality of charge-density waves (CDW) in 1T-TiSe₂ by using STM and time-domain optical polarimetry. We found that the CDW intensity becomes Ia₁∶Ia₂∶Ia₃ = 1∶0.7 ± 0.1∶0.5 ± 0.1, where Ia(i) (i=1,2,3) is the amplitude of the tunneling current contributed by the CDWs. There were two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise. The chirality in CDW results in the threefold symmetry breaking. Macroscopically, twofold symmetry was indeed observed in optical measurement. We propose the new generalized CDW chirality H(CDW) ≡ q₁·(q₂×q₃), where q(i) are the CDW q vectors, which is independent of the symmetry of components. The nonzero H(CDW)-the triple-q vectors do not exist in an identical plane in the reciprocal space-should induce a real-space chirality in CDW system.

A physiologically based pharmacokinetic model for valnemulin in rats and extrapolation to pigs

A flow-limited, physiologically based pharmacokinetic (PBPK) model for predicting the plasma and tissue concentrations of valnemulin after a single oral administration to rats was developed, and then the data were extrapolated to pigs so as to predict withdrawal interval in edible tissues. Blood/tissue pharmacokinetic data and blood/tissue partition coefficients for valnemulin in rats and pigs were collected experimentally. Absorption, distribution and elimination of the drug were characterized by a set of mass-balance equations. Model simulations were achieved using a commercially available software program. The rat PBPK model better predicted plasma and tissue concentrations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, lung and muscle were 0.96, 0.94, 0.96, 0.91 and 0.91, respectively. The rat model parameters were extrapolated to pigs to estimate valnemulin residue withdrawal interval in edible tissues. Correlation (R(2) ) between predicted and observed liver, kidney and muscle were 0.95, 0.97 and 0.99, respectively. Based on liver tissue residue profiles, the pig model estimated a withdrawal interval of 10 h under a multiple oral dosing schedule (5.0 mg/kg, twice daily for 7.5 days). PBPK models, such as this one, provide evidence of the usefulness in interspecies PK data extrapolation over a range of dosing scenarios and can be used to predict withdrawal interval in pigs.

Variation characteristics of the nitrate reductase gene of key inbred maize lines and derived lines in China

Key inbred lines have played a fundamental role in maize genetics and breeding. Research on variation characteristics of key genes from key inbred lines and from derived lines is important for early identification and evaluation of inbred maize lines. The nitrate reductase (NR) gene, which plays a central role in nitrate acquisition, was the target gene for this research. Forty-one inbred maize lines were investigated, including four key inbred lines: Huangzaosi, Mo17, Dan340, and Ye478. Through multiple sequence alignment with the NR gene from B73, used as a control, we found that: 1) the NR gene of most inbred lines from Huangzaosi and from derived lines had two insertion fragments and two replacement fragments; 2) the NR gene of most inbred lines from Mo17 and derived lines had one insertion fragment and one replacement fragment; 3) there were two common variations and eight common SNPs in the NR gene of the four key lines. Huangzaosi and Mo17 also had three common variations compared with the other key lines. Moreover, Mo17 had some unique variations; there were no unique variations in the other key lines, even for SNPs, and 4) phylogenetic tree analysis showed that the NR gene of the derived lines from the same key line had higher sequence homology. Based on the above NR gene variation characteristics and sequence homology of key inbred lines and derived lines, a candidate inbred line can be preliminarily selected and evaluated by marker development and/or sequence alignment of the NR gene.

Automated segmentation for patella from lateral knee X-ray images

X-ray image segmentation is an important issue in medical image analysis. Due to inconsistent X-ray absorption, the intensities are usually unevenly distributed and noisy in the processed organ, thus the object segmentation becomes difficult. In this paper we propose a new segmentation method for patella from the lateral knee X-ray images based on the active shape model (ASM). At first, a patella shape model is constructed by principal component analysis (PCA) of corresponding landmarks obtained from a set of training shape. As the knee X-ray image usually contains many anatomical structures, we design a strategy based on edge tracing to place the initial shape model as close to the patella boundary as possible. Then, the shape model is deformed and fitted to the patella boundary by using a dual-optimization approach that includes a genetic algorithm (GA) to get the global geometric transform and ASM to deform the shape model iteratively. Consequently, the proposed method can cope with different knee X-ray images and can segment the patella in an automatic procedure. In the experiment, 20 images were tested and promising results are obtained by the proposed method. This method is found useful for the clinical evaluation and biomechanical study of knee.

A comparative cytogenetic study of the rice (Oryza sativa L.) autotetraploid restorers and hybrids

We studied pollen fertility, seed set and cytogenetic characteristics of restorer lines and F1 hybrids of autotetraploid rice. T4002, T4063, T461A x T4002 and T461A x T4063 showed significantly higher pollen fertility and seed set than T4132 and T461A x T4132. Meiotic pairing configurations of T4002, T4063, T4132, T461A x T4002, T461A x T4063 and T461A x T4132 were 0.051 + 19.96II (9.89 rod + 10.07 ring) + 0.01III + + 2.00IV, 0.11I + 19.17II (8.90 rod + 10.37 ring) + 0.09III + 2.26IV + 0.01VI, 1.34I + 9.46II (4.50 rod + 4.96 ring) + 0.80III + 6.02IV + 0.09VI + 0.09VIII, 0.02I + 14.36II (6.44 rod + 7.91 ring) + 0.01III + 4.80IV + 0.01VIII, 0.06I + 17.67II (11.01 rod + 6.67 ring) + 0.06III + 3.10IV + 0.01VI and 1.11I + 11.31II (5.80 rod + 5.51 ring) + 0.41III + 5.63IV + 0.03VI + 0.03VIII, respectively. Configuration 16II + 4IV and 12II + 6IV occurred in the highest frequency among the autotetraploid restorers and hybrids. Meiotic chromosome behaviors were less abnormal in the tetraploids with high seed set than those with low seed set. The hybrids had fewer frequencies of bivalents, univalents, trivalents and multivalents than the restorers, but higher frequency of quatrivalents than the restorers at MI. The frequency of univalents at MI had the most impact on pollen fertility and seed set, i.e., pollen fertility decreased with the increase of univalents. The secondary impact factors were trivalents and multivalents, and bivalents and quatrivalents had no effect on pollen fertility and seed set. The correlative relationship between pollen fertility and cytogenetic behaviors could be utilized to improve seed set in autotetraploidy breeding.

Tetraethylammonium inhibits glioma cells via increasing production of intracellular reactive oxygen species

BACKGROUND

Potassium channel blockers have been shown to possess antitumor properties, but the role of apoptosis remains to be clarified. In this study, we investigated the antiproliferative effect of tetraethylammonium (TEA), a nonspecific potassium channel blocker, in rat C6 and 9L glioma cells.

METHODS

Cytotoxicity was evaluated by MTT assay. Apoptosis was detected by TUNEL and annexin V-FITC/propidium iodide assays. Protein levels were determined by Western blot analysis. Intracellular reactive oxygen species (ROS) levels were assessed flow cytometrically.

RESULTS

TEA (2-60 mM) significantly inhibited the proliferation of C6 and 9L glioma cells. In addition, increased cell apoptosis was confirmed after treatment with 40 mM TEA. Apoptosis was associated with a dramatic increase in ROS levels and altered Bcl-2/Bax protein balance.

CONCLUSION

TEA can inhibit proliferation and induce apoptosis in both cell lines; therefore, it might be associated with the increase in intracellular ROS production.

Thermodynamic origins of shear band formation and the universal scaling law of metallic glass strength

We report a universal scaling law, tau_{y} = 3R(T_{g}-RT)/V, that uncovers an inherent relationship of the yield strength tau_{y} with the glass transition temperature T_{g} and molar volume V of metallic glasses. This equation is derived from fundamental thermodynamics and validated by various metallic glasses with well-defined yielding. The linearity between tau_{y} and T_{g} demonstrates the intrinsic correlation between yielding and glass-liquid transition, which contributes to the basic understanding of the strength and deformation of glassy alloys.

Increase of the beam intensity for BNCT by changing the core configuration at THOR

In this article, we will consider several core configurations and run the core calculation with MCNP to obtain the neutrons distribution at THOR. The thermal neutron flux inside the vertical tubes (VT-B-VT-E) and the fast neutron flux in the first row facing to the boron neutron capture therapy (BNCT) facility (I3-I5) were tallied for indication. Based on these simulation results, the fuel elements were rearranged during the annual repair period in 2007. The epithermal neutron flux at the center of BNCT beam exit in air was measured again, and the results showed that the beam intensity increased by 50%. Comparing the neutron intensities both in reactor core and at the BNCT beam exit for several core configurations, the results show that the BNCT beam intensity can be increased without decreasing the neutron intensity in core.

Composition, distribution, and characterization of polycyclic aromatic hydrocarbons in soil in Linfen, China

A total of 10 surface soil samples representing the entire area of Linfen City were collected and analyzed for the presence of 16 polycyclic aromatic hydrocarbons. The total polycyclic aromatic hydrocarbon concentration ranged from 1.1 to 63.7 microg g(-1). Analysis of the sources of contamination revealed that polycyclic aromatic hydrocarbons in the soil were derived from combustion sources. Specifically, the primary source of polycyclic aromatic hydrocarbons was coal combustion, but the samples were also effected to varying degrees by traffic emissions. Furthermore, increased levels of contamination were observed in northeast Linfen due to the distribution of industrial plants.

Variations in quality of carbol fuchsin stains collected from routine tuberculosis laboratories

SETTING

In-use carbol fuchsin stains were collected from 10 different routine acid-fast bacilli smear microscopy laboratories.

OBJECTIVE

To examine the variations in the composition of carbol fuchsin stains.

METHOD

Carbol fuchsin concentrations were first determined spectrophotometrically by measuring absorbance at 547 nm. High-performance liquid chromatography (HPLC) separated and quantified the four basic fuchsin homologues: para-rosaniline, rosaniline, magenta II and new fuchsin, and identity was confirmed by mass spectrometry (MS).

RESULTS

Absorbance measurement showed that three of 10 (30%) samples contained insufficient carbol fuchsin (<70%). Wide variations in relative proportions of fuchsin homologues were found.

CONCLUSION

The relative abundance of rosaniline + new fuchsin was quite stable among the different laboratories. Spectrophotometry and HPLC/MS are necessary and sensitive tools for monitoring fuchsin quality.

Organochlorine pesticides in the soil in Linfen, China

Ten soil samples collected in Linfen were analyzed for 21 organochlorine pesticides. The concentration of total organochlorine pesticides ranged from 4.3 to 23.2 ng g(-1) in soil from urban areas and from 26.3 to 247.4 ng g(-1) in soil from industrial plants. The highest levels of contamination were observed in northwest and central Linfen, reflecting the distribution of industrial plants. The HCH and DDT profiles revealed that the sources were associated mainly with lindane and technical DDT, respectively, while HCHs in the soil of industrial plants might originate from a new source.

Self-assembly of complex structures in a two-dimensional system with competing interaction forces

Self-assembly of minimum-energy configurations of a two-dimensional system consisting of charged particles confined in a quadratic trap and interacting through competing repulsive and attractive interparticle forces is studied by means of molecular dynamics simulation. It is shown that complex configurations, including concentric shells separated by bandlike voids, connected shells with multiple regularly arranged voids, as well as small clusters of particles organized into crystal- or liquidlike structures, can exist. With increase of the particle number, a larger variety of structural patterns becomes possible. The results here are useful for a better understanding of pattern formation in two-dimensional systems, as well as in the design of specific structures for technological applications.

[Characterization and expression profiling of a novel cereal cyst nematode resistance gene analog in wheat]

Based on the conserved regions of known resistance genes, a NBS-LRR type CCN resistance gene analog was isolated from the CCN resistant E-10 near isogenic lines (NILs) of wheat, designated as CreZ (GenBank Acc. N: EU327996). It contained a complete ORF that was 2775 bp in length and encoded 924 amino acids. Sequence comparison indicated that it shared 92% nucleotide and 87% amino acid identity with those of the known CCN-resistance gene Cre3 and had similar characteristic conserved motifs as those in other established NBS-LRR disease resistance genes. The expression profiling of CreZ indicated that it was specifically expressed in the roots of resistant plants and real-time PCR analysis demonstrated that expression levels drastically increased when the plants were inoculated with cereal cyst nematodes. It could be inferred, then, that CreZ belongs to the NBS-LRR resistance gene family and is a candidate gene for potential resistance to the cereal cyst nematode.

Direct observation of the coexistence of the pseudogap and superconducting quasiparticles in Bi2Sr2CaCu2O8 + y by time-resolved optical spectroscopy

We report the ultrafast optical response of quasiparticles (QPs) in both the pseudogap (PG) and superconducting (SC) states of an underdoped Bi2Sr2CaCu2O8 + y (Bi2212) single crystal measured with the time-resolved pump-probe technique. At a probe energy variant planck's over omegapr = 1.55 eV, it is found that the reflectivity change DeltaR/R changes its sign at exactly Tc, which allows the direct separation of the charge dynamics of PG and SC QPs. Further systematic investigations indicate that the transient signals associated with PG and SC QPs depend on the probe beam energy and polarization. By tuning them below Tc, two distinct components can be detected simultaneously, providing evidence for the coexistence of PG and SC QPs.

Salvage surgery after failed chemoradiotherapy in squamous cell carcinoma of the esophagus

AIMS

To investigate the survival benefit and preoperative risk factors for hospital mortality of salvage surgery in esophageal cancer patients who had locoregional residual/recurrent tumor after definitive chemoradiotherapy.

METHODS

We retrospectively reviewed the esophageal cancer patients who presented at our hospital from 1997 to 2004. Forty-seven patients who had squamous cell cancer and developed locoregional recurrent/persistent disease after primary definitive chemoradiotherapy were elected. Twenty-seven of them received salvage esophagectomy (group 1) and the other 20 underwent non-operative treatment only (group 2). In order to assess the surgery-related mobility and mortality in group 1, 191 patients who received neoadjuvant chemoradiotherapy followed by operation during the same time period were also enrolled (group 3).

RESULTS

The 5-year overall survival of group 1 patients was 25.4%. In contrast, all of the patients in the group 2 died within 16.7 months. The difference was statistically significant (p=0.0029). In comparison with group 3, group 1 patients had significantly more surgery-related complications and hospital mortality. In univariate analysis for preoperative risk factors, a low albumin or hemoglobulin level was associated with high hospital mortality in group 1 (p=0.004 and 0.003, respectively). After multivariate analysis, only the low albumin level remained borderline significance. As for disease specific survival after salvage surgery, R0 resection was the only independent prognosticator (p=0.049).

CONCLUSION

Salvage surgery provides survival benefit in esophageal cancer patients with locoregional persistent or recurrent disease after primary definitive chemoradiotherapy. Preoperative albumin and hemoglobulin levels are associated with hospital mortality and may aid in selecting suitable patient for salvage surgery.

Langerhans' cell histiocytosis with multisystem involvement in an adult

A 32-year-old Chinese woman presented for further investigation with a 6-year history of polyuria and polydipsia, a 4-year history of vulva ulceration and a 2-year history of gingival swelling. A biopsy of the vulva lesion showed diffuse infiltration of medium-sized cells with lobulated, grooved, vesicular nuclei. Occasional mitoses were present. The infiltrate of the cells showed reactivity with antibody to S-100 protein and CD1a, confirming the diagnosis of Langerhans' cell histiocytosis (LCH). Cephalic magnetic resonance imaging scanning revealed that an 8 x 7 x 8 mm3 large mass was located at the pituitary stalk. An X-ray film of the jaw showed sharply demarcated rarefaction of the right posterior portion of the mandible. In women with diabetes insipidus and genital ulcer, LCH should be considered in the differential diagnosis.

Low-dose haloperidol prevents post-operative nausea and vomiting after ambulatory laparoscopic surgery

BACKGROUND

We evaluated the prophylactic effect of low-dose haloperidol (1 mg) on post-operative nausea and vomiting (PONV) in women undergoing ambulatory laparoscopic surgery. Droperidol (0.625 mg) and saline were controls.

METHODS

One hundred and fifty women undergoing ambulatory laparoscopic surgery under general anaesthesia were enrolled in this randomized, double-blind, and placebo-controlled study. After tracheal intubation, the haloperidol group (n=50) received intravenous haloperidol (1 mg), the droperidol group (n=50) received intravenous droperidol (0.625 mg), and the saline group (n=50) received intravenous saline.

RESULTS

Haloperidol- and droperidol-group patients reported a lower incidence of PONV [24% and 23% vs. 49% (saline group); P<0.05] and requested fewer doses of rescue antiemetics [13% and 16% vs. 38% (saline group); P<0.05] during the first four post-operative hours. During the 24-h post-operative period, haloperidol- and droperidol-group patients also reported a lower incidence of PONV [31% and 32% vs. 62% (saline group); P<0.01]. No differences were found between the haloperidol and droperidol groups.

CONCLUSION

Like droperidol (0.625 mg), prophylactic intravenous haloperidol (1 mg) significantly reduced the incidence of PONV in women undergoing ambulatory laparoscopic surgery.

Osteoblast response to fluid induced shear depends on substrate microarchitecture and varies with time

Osteoblasts are exposed to fluid shear in vivo but the effects are not well understood, particularly how substrate properties or length of exposure modify the response. Short exposure (1 h) to shear reduces the stimulatory effect of micron-scale surface structure on osteoblast differentiation, but the effects of longer term exposures are not known. To test the hypothesis that substrate-dependent responses of osteoblasts to shear depend on the length of exposure to fluid flow, MG63 osteoblasts were grown on tissue culture glass, which has an average roughness (Ra) < 0.2 microm; machined Ti disks (PT, Ra < 0.6 microm); Ti disks with a complex microarchitecture [sand blasted acid etched (SLA), Ra = 4-5 microm); and Ti plasma-sprayed surfaces [Ti via plasma spray (TPS), Ra = 7 microm]. Confluent cultures were exposed to pulsatile flow at shear forces of 0, 1, and 14 dynes/cm(2) for 0, 6, 12, and 24 h. Shear reduced cell number on all surfaces, with greatest effects on TPS. Shear had no effect on alkaline phosphatase on smooth surfaces but increased enzyme activity on SLA and TPS in a time-dependent manner. Its effects on osteocalcin, TGF-beta1, and PGE(2) in the conditioned media were greatest on these surfaces as well. Responses to fluid-induced shear were blocked by the general Cox inhibitor indomethacin and the Cox-2 inhibitor meloxicam, indicating that response to shear is mediated by prostaglandin produced via a Cox-2 dependent mechanism. These results show that the effects of fluid induced shear change with time and are substrate dependent, suggesting that substrate microarchitecture regulates the osteoblast phenotype and effects of shear are determined by the maturation state of the responding population.

Double spectral theorem and two type magnitude-squared coherence functions

Studying frequency domain representation for the coherence between two signals is an important basic theoretical problem in the fundamental theories of signal processing. However, the old magnitude-squared coherence function (OMSCF) has been proved identical to 1, so that to cannot be used to extract any coherence information. Here, we will prove a core theorem in frequency domain coherence theories in signal processing, called as the double spectral theorem (DST). Based on the theorem, we presented the two types of new magnitude-squared coherence functions (MSCFs), called as the same type magnitude-squared coherence function (SMSCF) and the difference magnitude-squared coherence function (DMSCF) respectively, which were mathematically derived from DST and the conditions that they are equal to 1 or 0 can be theoretically derived from DST. Here, we further demonstrated that SMSCF and DMSCF could be used to exactly extract the coherence between two signals by each component.