Quantum theory for cold avalanche ionization in solids

A theory of photon-assisted impact ionization in solids is presented. Our theory makes a quantum description of the new impact ionization-cold avalanche ionization recently reported by P. P. Rajeev, M. Gertsvolf, P. B. Corkum, and D. M. Rayner [Phys. Rev. Lett. 102, 083001 (2009)]. The present theory agrees with the experiments and can be reduced to the traditional impact ionization expression in the absence of a laser.

Relationship of a dominant advanced glycation end product, serum carboxymethyl-lysine, and abnormal glucose metabolism in adults: the Baltimore Longitudinal Study of Aging

BACKGROUND AND OBJECTIVES

Although hyperglycemia is thought to increase the generation of advanced glycation end products (AGEs), studies have not shown a consistent relationship between abnormal glucose metabolism and serum AGEs. We investigated the relationship between a dominant serum AGE, N-carboxymethyl-lysine (CML), and glucose metabolism.

SUBJECTS AND METHODS

Serum CML, fasting plasma glucose, and glucose tolerance were measured in 755 adults in the Baltimore Longitudinal Study of Aging. Fasting plasma glucose was categorized as normal (< or = 99 mg/dL), impaired (100-125 mg/dL), and diabetic (> 125 mg/dL). Two-hour plasma glucose on oral glucose tolerance testing was categorized as normal (< or = 139 mg/dL), impaired (140-199 mg/dL), and diabetic (> or = 200 mg/dL).

RESULTS

The proportion of adults with normal, impaired, and diabetic fasting plasma glucose was 73.8%, 22.9%, and 2.9%, respectively, and the proportion with normal, impaired, and diabetic 2-hour plasma glucose was 73.1%, 19.2%, and 7.7%, respectively. Serum CML (microg/mL) was not associated with abnormal fasting plasma glucose (Odds Ratio [O.R.] 0.60, 95% Confidence Interval [C.I.] 0.15-2.36, P = 0.47) in a multivariate, ordered logistic regression model, adjusting for age, race, gender, body mass index, and chronic diseases. Serum CML (microg/mL) was associated with abnormal 2-hour plasma glucose on glucose tolerance testing (O.R. 0.15, 95% C.I. 0.04-0.63, P = 0.009) in a multivariate, ordered logistic regression model, adjusting for the same covariates.

CONCLUSIONS

Elevated CML, a dominant AGE, was not associated with elevated fasting plasma glucose and was associated with a reduced odds of abnormal glucose tolerance in older community-dwelling adults.

Light emission from nanoscale Si/Si oxide materials

Most porous Si materials studied have been oxidized in various degrees. The oxidized porous Si comprises of a great quantity of nanoscale Si particles (NSPs) and each of them is covered by a Si oxide layer. The structure and luminescence properties of the NSPs embedded Si oxide and the nanoscale Si/nanoscale SiO2 multilayers are similar to those of the oxidized porous Si. All the three kinds of materials mentioned are called nanoscale Si/Si oxide materials and their photoluminescence and electroluminescence properties especially light emission mechanisms are reviewed in this article. Nanoscale Si/Si oxide materials have been well studied and are believed to be very promising Si based light emitting materials. The very distinct roles of the NSPs and the luminescence centers in Si oxide in the photoluminescence and electroluminescence from the nanoscale Si/Si oxide materials are highlighted.

Relationship of 25-hydroxyvitamin D with all-cause and cardiovascular disease mortality in older community-dwelling adults

Background/Objectives

Vitamin D deficiency is associated with cardiovascular disease, osteoporosis, poor muscle strength, falls, fractures, and mortality. Although older adults are at a high risk of vitamin D deficiency, the relationship of serum 25(OH)D with all-cause and cardiovascular disease mortality has not been well characterized in the elderly. We hypothesized that low serum 25(OH)D predicted mortality in older adults.

Subjects/Methods

Serum 25(OH)D and all-cause and cardiovascular disease mortality were examined in 1006 adults, ≥65 years, who participated in the InCHIANTI study, a population-based, prospective cohort study of aging in Tuscany, Italy. Serum 25(OH)D was measured at enrollment in 1998-1999, and participants were followed for mortality.

Results

During 6.5 years of follow-up, 228 (22.7%) participants died, of whom 107 died from cardiovascular disease. Compared with participants in the highest quartile of serum 25(OH)D (>26.5 ng/mL)(to convert to nmol/L, multiply by 2.496), those in the lowest quartile (<10.5 ng/mL) had increased risk of all-cause mortality (Hazards Ratio [H.R.] 2.11, 95% Confidence Interval [C.I.] 1.22 – 3.64, P = 0.007) and cardiovascular disease mortality (H.R. 2.64, 95% C.I. 1.14 – 4.79, P = 0.02), in multivariate Cox proportional hazards models that adjusted for age, sex, education, season, physical activity, and other potential confounders.

Conclusions

Older community-dwelling adults with low serum 25(OH)D are at higher risk of all-cause and cardiovascular disease mortality.

Expression of progesterone receptor A form and its role in the interaction of progesterone with cortisol on cyclooxygenase-2 expression in amnionic fibroblasts

CONTEXT

Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is believed to be one of the major events leading to parturition. Glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression, the crucial enzyme catalyzing prostaglandin synthesis, in human amnion fibroblasts. Although a major propregnancy hormone, the effect of progesterone and the associated progesterone receptor subtypes in the regulation of both basal and glucocorticoid-induced COX-2 expression in human amnion fibroblasts have not been resolved.

METHODS AND RESULTS

Cultured human amnion fibroblasts prepared from the fetal membranes at term pregnancy without labor mainly expressed the progesterone receptor A form (PRA). Inhibition of endogenous progesterone production with trilostane or knockdown of PRA expression with small interfering RNA significantly enhanced the glucocorticoid receptor (GR)-mediated COX-2 induction by cortisol, whereas overexpression of PRA attenuated the induction by cortisol. Co-immunoprecipitation assay revealed PRA in the GR protein complex. Although exogenous progesterone did not alter COX-2 expression under basal conditions, it attenuated cortisol-induced COX-2 expression at concentrations about 10- to 50-fold higher, which might be achieved by competition with cortisol for GR.

CONCLUSIONS

We demonstrated in this study that endogenous progesterone might counteract the induction of prostaglandin synthesis by cortisol via PRA transdominant repression of GR function, whereas high levels of progesterone might further inhibit the induction by cortisol via competitive binding to GR in human amnion fibroblasts. These inhibitory actions of progesterone and PRA on glucocorticoids and GR may partly explain the inconsistent effects of glucocorticoids on parturition in humans.

Immune responses to T-cell epitopes of SARS CoV-N protein are enhanced by N immunization with a chimera of lysosome-associated membrane protein

In our previous study by Gupta et al, dominant T-cell epitopes of SARS CoV-N(N) protein were predicted by software. The spectrum of interferon (IFN)-gamma responses of Balb/c mice immunized against two different forms of SARS CoV-N plasmid was then analyzed. A cluster of dominant T-cell epitopes of SARS CoV-N protein was found in the N-terminus (amino acids 76-114). On the basis of this study, four different plasmids were constructed: (i) DNA encoding the unmodified N (p-N) or N(70-122) (p-N(70-122)) as an endogenous cytoplasmic protein or (ii) DNA encoding a lysosome-associated membrane protein (LAMP) chimera with N (p-LAMP/N) or N(70-122) (p-LAMP/N(70-122)). The immune responses of mice to these four constructs were evaluated. The results showed marked differences in the responses of the immunized mice. A single priming immunization with the p-LAMP/N construct was sufficient to elicit an antibody response. Enzyme-linked immunospot (ELISpot) assay indicated that p-LAMP/N(70-122) and p-LAMP/N plasmids both elicited a greater IFN-gamma response than p-N. p-N and p-N(70-122) constructs induced low or undetectable levels of cytokine secretion. We also found that the p-LAMP/N(70-122) construct promoted a long-lasting T-cell memory response without an additional boost 6 months after three immunizations. These findings show that DNA vaccines, even epitope-based DNA vaccines using LAMP as chimera, can elicit both humoral and cellular immune responses.

Role of human chorionic gonadotropin in maintaining 11beta-hydroxysteroid dehydrogenase type 2 expression in human placental syncytiotrophoblasts

Proper glucocorticoid exposure in utero is vital for normal fetal organ maturation, but excess glucocorticoids are detrimental to fetal growth and can even predispose the individuals to the high risk of having certain diseases in adulthood. The fetus is protected from 10 times higher maternal glucocorticoid levels by the placental enzyme 11beta-hydroxysteroid dehydrogenase 2 (11beta-HSD2), which converts biologically active cortisol to inactive cortisone. Thus it is of primary importance to understand how this enzyme is regulated. Activation of cAMP/PKA pathway is known to upregulate 11beta-HSD2 expression in placental syncytiotrophoblasts, however the endogenous hormones utilizing this pathway remain largely unknown. By using cultured human placental syncytiotrophoblasts, we demonstrated that inhibition of protein kinase A with H89 attenuated 11beta-HSD2 expression in the syncytiotrophoblasts, suggesting endogenous factors from the syncytiotrophoblasts using this pathway to maintain 11beta-HSD2 expression in the syncytiotrophoblasts. Neutralization of human chorionic gonadotropin (hCG) secreted by the syncytiotrophoblasts with hCG antibody decreased 11beta-HSD2 promoter activity, mRNA and protein expression as well as intracellular cAMP level, while treatment of the syncytiotrophoblasts with exogenous hCG increased 11beta-HSD2 expression, which was attenuated by H89. Furthermore, we found that cortisol increased both hCG expression and secretion. The up-regulation of 11beta-HSD2 expression by cortisol was significantly attenuated by co-treatment with hCG antibody or H89 in the syncytiotrophoblasts. In conclusion, hCG is an important paracrine or autocrine hormone maintaining 11beta-HSD2 expression and the up-regulation of 11beta-HSD2 expression by cortisol may be mediated in part by hCG in the syncytiotrophoblasts.

Paradoxical stimulation of cyclooxygenase-2 expression by glucocorticoids via a cyclic AMP response element in human amnion fibroblasts

Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is one of the major events leading to parturition. In marked contrast to its well-described antiinflammatory effect, glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression in human amnion fibroblasts. The mechanisms underlying this paradoxical induction of COX-2 by glucocorticoids have not been resolved. Using cultured human amnion fibroblasts, we found that the induction of COX-2 mRNA expression by cortisol was a glucocorticoid receptor (GR)-dependent process requiring ongoing transcription. Upon transfection of a COX-2 promoter-driven reporter gene into the amnion fibroblasts, cortisol stimulated the COX-2 promoter activity. This was abolished by mutagenesis of a cAMP response element (CRE) at -53 to approximately -59bp as well as by cotransfection of a plasmid expressing dominant-negative CRE-binding protein (CREB). The phosphorylation level of CREB-1 was significantly increased by cortisol treatment of the amnion fibroblasts, whereas the effect was attenuated either by the protein kinase A inhibitor H89 or the p38 -MAPK inhibitor SB203580. The induction of the COX-2 promoter activity and the phosphorylation of CREB-1 were also blocked by the GR antagonist RU486. Chromatin immunoprecipitation (ChIP) assay revealed that the binding of CREB-1 to the CRE of the COX-2 promoter was increased by cortisol treatment of the amnion fibroblasts. In conclusion, cortisol, via binding to GR, stimulated COX-2 expression by increasing phosphorylated CREB-1 binding to the CRE of the COX-2 gene. Cortisol may phosphorylate CREB-1 by activating either protein kinase A or p38-MAPK in the amnion fibroblasts.

Calibrated finger rub auditory screening test (CALFRAST)

BACKGROUND

Determination of auditory function is a fundamental part of a complete neurologic examination. Disability from permanent hearing loss is common in the general population. Current bedside auditory tests are unreliable and cumbersome. We evaluated the calibrated finger rub auditory screening test (CALFRAST) as a routine diagnostic tool.

METHODS

The sound spectrum and mean peak intensities of standard finger rub were measured, as well as background noise. CALFRAST overlapped the frequency spectrum of normal speech. Patients and companions were recruited from a neurology clinic. With arms extended, two stimulus intensities were presented: strong finger rub (CALFRAST-Strong 70) and the faintest rub that the examiner could hear (CALFRAST-Faint 70). With subjects' eyes closed, each ear's CALFRAST threshold was ascertained and then compared with its audiometric measure. The normal threshold was considered to be 25 dB. Validity, reliability, and discrimination abilities were obtained using standard methods.

RESULTS

Two hundred twenty-one subjects (442 ears; 58% women) were examined. Ages ranged from 18 to 88 years, with a mean of 46 years. Eighty-five subjects (39%) had some degree of hearing loss. Both specificity and positive predictive value of CALFRAST-Strong 70 were 100%. Both sensitivity and negative predictive value of CALFRAST-Faint 70 were 99%, with a negative likelihood ratio <0.1. Area under the receiver operating characteristic curve was 0.94, consistent with excellent discrimination ability. Both intrarater and interrater reliability were excellent, both kappa >0.8. Subjects' self-assessment of hearing was unreliable.

CONCLUSION

The calibrated finger rub auditory screening test (CALFRAST) is simple, accurate, inexpensive, and reliable. As a routine screening tool, CALFRAST may contribute to more efficient identification of auditory impairment.

Output characterization of a self-pulsating and aperiodic optical fiber source based on cascaded regeneration

We investigate the properties of a self-pulsating fiber cavity based on cascaded regeneration. The mechanisms that govern the number of oscillating pulses in the cavity, the pulse peak power, the pulse width, the wavelength tunability as well as the generation of sub-picosecond pulses are identified, analyzed and quantified. We find that the described self-pulsating cavity enables the oscillation of quasi transform-limited pulses with a pulsewidth of 4.8 ps at 1540.0 nm when using 0.4 nm non-Gaussian bandpass filters. Sub-picosecond pulses with an autocorrelation width of 471 fs are generated from the same self-pulsating source with modified bandpass filters and the addition of a chromatic dispersion compensator. The number of eigenpulses that oscillate simultaneously in the cavity can be adjusted from 0 up to 29,500 with proper cavity adjustment. This source has dual-wavelength output and can be tuned throughout the gain band of the amplifiers.

Identification of vhhP2, a novel genetic marker of Vibrio harveyi, and its application in the quick detection of V. harveyi from animal specimens and environmental samples

AIMS

To investigate the species-specific prevalence of vhhP2 among Vibrio harveyi isolates and the applicability of vhhP2 in the specific detection of V. harveyi from crude samples of animal and environmental origins.

METHODS AND RESULTS

A gene (vhhP2) encoding an outer membrane protein of unknown function was identified from a pathogenic V. harveyi isolate. vhhP2 is present in 24 V. harveyi strains isolated from different geographical locations but is absent in 24 strains representing 17 different non-V. harveyi species, including V. parahaemolyticus and V. alginolyticus. A simple polymerase chain reaction method for the identification of V. harveyi was developed based on the conserved sequence of vhhP2. This method was demonstrated to be applicable to the quick detection of V. harveyi from crude animal specimens and environmental samples. The specificity of this method was tested by applying it to the examination of two strains of V. campbellii, which is most closely related to V. harveyi. One of the V. campbellii strains was falsely identified as V. harveyi.

CONCLUSIONS

vhhP2 is ubiquitously present in the V. harveyi species and is absent in most of the non-V. harveyi species; this feature enables vhhP2 to serve as a genetic marker for the rapid identification of V. harveyi. However, this method can not distinguish some V. campbellii strains from V. harveyi.

SIGNIFICANCE AND IMPACT OF THE STUDY

the significance of our study is the identification of a novel gene of V. harveyi and the development of a simple method for the relatively accurate detection of V. harveyi from animal specimens and environmental samples.

Ex vivo inhibition of NF-kappaB signaling in alloreactive T-cells prevents graft-versus-host disease

The ex vivo induction of alloantigen-specific hyporesponsiveness by costimulatory pathway blockade or exposure to immunoregulatory cytokines has been shown to inhibit proliferation, IL-2 production, and the graft-versus-host disease (GVHD) capacity of adoptively transferred T-cells. We hypothesized that inhibition of the intracellular NF-kappaB pathway in alloreactive T-cells, which is critical for T-cell activation events including IL-2 transcription, could lead to alloantigen hyporesponsiveness and loss of GVHD capacity. We demonstrate that treatment of mixed lymphocyte reaction (MLR) cultures with PS1145, a potent inhibitor of NF-kappaB activation, can induce T-cell hyporesponsiveness to alloantigen in primary and secondary responses while preserving in vitro responses to potent mitogenic stimulation. GVHD lethality in recipients of ex vivo PS1145-treated cells was profoundly inhibited. Parking of control or PS1145-treated MLR cells in syngeneic Rag(-/-) recipients resulted in intact contact hypersensitivity (CHS) responses. However, GVHD lethality capacity also was restored, suggesting that lymphopenic expansion uncoupled alloantigen hyporesponsiveness. These results indicate that the NF-kappaB pathway is a critical regulator of alloresponses and provide a novel small molecule inhibitor based approach that is effective in preventing early posttransplant GVHD lethality but that also permits donor T-cell responses to recover after a period of lymphopenic expansion.

Low serum carotenoids are associated with a decline in walking speed in older women

BACKGROUND AND OBJECTIVES

Walking speed is an important measure of physical performance that is predictive of disability and mortality. The relationship of dietary factors to changes in physical performance has not been well characterized in older adults. The aim was to determine whether total serum carotenoid concentrations, a marker for fruit and vegetable intake, and serum selenium are related to changes in walking speed in older women.

SUBJECTS AND METHODS

The relationship between total serum carotenoids and selenium measured at baseline, 12, and 24 months follow-up and walking speed assessed at baseline and every six months for 36 months was examined in 687 moderately to severely disabled women, 65 years or older, living in the community.

RESULTS

Mean total serum carotenoids were associated with mean walking speed over three years of follow-up (P = 0.0003) and rate of change of walking speed (P = 0.007) in multivariate linear regression models adjusting for age, body mass index, and chronic diseases. Mean serum selenium was associated with mean walking speed over three years of follow-up (P = 0.0003) but not with the rate of change of walking speed (P = 0.26).

CONCLUSIONS

These findings suggest that a higher fruit and vegetable intake, as indicated by higher total serum carotenoid concentrations, may be protective against a decline in walking speed in older women.

1.53 µm photo- and electroluminescence from Er(3+) in erbium silicate

Si-rich silicon oxide (SRO)/Er-Si-O/SRO multilayers were prepared on p-Si substrates using magnetron sputtering. X-ray diffraction measurements indicate that a mixture of silicates Er(2)Si(2)O(7) and Er(2)SiO(5) was formed after the multilayers were annealed at 1000 and 1150 °C. Strong Er(3+) 1.53 µm photoluminescence (PL) at room temperature has been observed from these multilayers and the full width at half-maximum of the 1.53 µm peak is less than 1.8 nm for the multilayers annealed at 1150 °C. Er(3+) 1.53 µm electroluminescence has been observed from erbium silicate films for the first time.

Manipulating the magnetic structure of Co core/CoO shell nanoparticles: implications for controlling the exchange bias

We present an experimental study of the effects of oxidation on the magnetic and crystal structures of exchange biased epsilon-Co/CoO core-shell nanoparticles. Transmission electron microscopy measurements reveal that oxidation creates a Co-CoO interface which is highly directional and epitaxial in quality. Neutron diffraction measurements find that below a Néel temperature TN of approximately 235 K the magnetization of the CoO shell is modulated by two wave vectors, q1=(1/2 1/2 1/2)2pi/a and q2=(100)2pi/a. Oxidation affects the q1 component of the magnetization very little, but hugely enhances the q2 component, resulting in the magnetic decompensation of the core-shell interface. We propose that the large exchange bias effect results from the highly ordered interface between the Co core and CoO shell, and from enhanced core-shell coupling by the uncompensated interface moment.

Combination of passivated Si anode with phosphor doped organic to realize highly efficient Si-based electroluminescence

Silicon light source plays a key role in silicon optoelectronics, but its realization is an extremely challenging task. Although there are longterm intensive efforts to this topic, the power conversion efficiency (PCE) of the silicon-based electroluminescence is still no more than 1%. In this present report, a highly efficient silicon light source has been achieved. The device structure is p-Si (5 Omegacm)/ SiO2(approximately 2 nm)/ NPB / CBP: (ppy)(2)Ir(acac) / Bphen /Bphen: Cs2CO3 / Sm / Au. The SiO2 passivated Si is the anode having a suitably high hole-injection ability, and CBP: (ppy)(2)Ir(acac) is a highly efficient phosphor doped organic material. The device turn-on voltage is 3.2 V. The maximum luminance efficiency and maximum luminous power efficiency reach 69 cd/A and 62 lm/W, respectively, corresponding to a maximum PCE of 12% and an external quantum efficiency of 17%.

Strong enhancement of Er(3+) 1.54 µm electroluminescence through amorphous Si nanoparticles

The roles of amorphous Si nanoparticles in light-emitting diodes (LEDs) based on Er-doped Si(1+x)O(2) films (x representing the degree of Si content, and varying widely from 0 to 4.50) have been investigated. In the aspect of the LEDs' electrical performance, it was found that the incorporation of Si nanoparticles facilitates the electrical conductivity of the films by improving the carrier mobility. With x increasing from 0 to 4.50, the mobility increases monotonically up to 5 times. The efficiency of Er(3+) electroluminescence (EL) at 1.54 µm can be enhanced by as much as 160 times when the degree of Si content x is 2.00, coincident with the value at which the rate of mobility increasing versus x slows down. The fact that the maximum of EL efficiency and the slowing down of the rate of increase of mobility occur at the same x value can be explained by coalescence of Si nanoparticles starting at x = 2.

Polymorphisms of ACE2 gene are associated with essential hypertension and antihypertensive effects of Captopril in women

ACE2 appears to counterbalance the vasopressor effect of angiotensin I converting enzyme (ACE) in the reninangiotensin system. We hypothesized that ACE2 polymorphisms could confer a high risk of hypertension and have an impact on the antihypertensive response to ACE inhibitors. The hypothesis was tested in two casecontrol studies and a clinical trial of 3,408 untreated hypertensive patients randomized to Atenolol, Hydrochlorothiazide, Captopril, or Nifedipine treatments for 4 weeks. ACE2 rs2106809 T allele was found to confer a 1.6-fold risk for hypertension in women (95% confidence interval (CI), 1.132.06), whereas when combined with the effect of the ACE DD genotype, the risk was 2.34-fold (95% CI, 1.754.85) in two independent samples. The adjusted diastolic blood pressure response to Captopril was 3.3 mm Hg lower in ACE2 T allele carriers than in CC genotype carriers (P=0.019) in women. We conclude that the ACE2 T allele confers a high risk for hypertension and reduced antihypertensive response to ACE inhibitors.

Development of Eddy Current Sensor systems in artificial heart for noncontact gap sensing

The axial flow pump has been developed in Korea Artificial Organ Center. It consists of an impeller, a motor and a magnetic bearing. The magnetic bearing fully levitates the impeller not to contact with other parts of pump. However, in order to control the gap between the impeller and other parts, continuous gap sensing is necessary. The conventional gap sensors are relatively large to implant in artificial heart. Thus, the compact eddy current sensor system proper for artificial heart was developed and the performances were evaluated. It showed good results and has small size. However, the dependency of the sensor upon temperature and target material was shown also. Moreover, the output of sensor had nonlinear responses. These must be calibrated in further study.

Recent progress of moving-actuator type mechanical circulatory support systems: AnyHeart and T-PLS

The mechanical circulatory support system using moving-actuator mechanisms were developed by Seoul National University and Korea University. AnyHeart is a fully implanted pulsatile bi-ventricular assist device, and T-PLS is a pulsatile flow versatile extracorporeal life support system. Through lots of in-vitro and in-vivo experiments, the developed mechanical systems are faced to produce on commercial scale. This paper describes the recent progress of two mechanical circulatory support systems, AnyHeart and T-PLS.

Transport of Escherichia coli bacteria through laboratory columns of glacial-outwash sediments: estimating model parameter values based on sediment characteristics

Bacterial transport through cores of intact, glacial-outwash aquifer sediment was investigated with the overall goal of better understanding bacterial transport and developing a predictive capability based on the sediment characteristics. Variability was great among the cores. Normalized maximum bacterial-effluent concentrations ranged from 5.4x10(-7) to 0.36 and effluent recovery ranged from 2.9x10(-4) to 59%. Bacterial breakthrough was generally rapid with a sharp peak occurring nearly twice as early as the bromide peak. Bacterial breakthrough exhibited a long tail of relatively constant concentration averaging three orders of magnitude less than the peak concentration for up to 32 pore volumes. The tails were consistent with non-equilibrium detachment, corroborated by the results of flow interruption experiments. Bacterial breakthrough was accurately simulated with a transport model incorporating advection, dispersion and first-order non-equilibrium attachment/detachment. Relationships among bacterial transport and sediment characteristics were explored with multiple regression analyses. These analyses indicated that for these cores and experimental conditions, easily-measurable sediment characteristics--median grain size, degree of sorting, organic-matter content and hydraulic conductivity--accounted for 66%, 61% and 89% of the core-to-core variability in the bacterial effective porosity, dispersivity and attachment-rate coefficient, respectively. In addition, the bacterial effective porosity, median grain size and organic-matter content accounted for 76% of the inter-core variability in the detachment-rate coefficient. The resulting regression equations allow prediction of bacterial transport based on sediment characteristics and are a possible alternative to using colloid-filtration theory. Colloid-filtration theory, used without the benefit of running bacterial transport experiments, did not as accurately replicate the observed variability in the attachment-rate coefficient.

Myometrial prostaglandin E2 synthetic enzyme mRNA expression: spatial and temporal variations with pregnancy and labour

We have investigated the hypothesis that the expression of the enzymes involved in PGE(2) synthesis in the human uterus is co-ordinated. We have studied (i) the mRNA expression of the enzymes involved in PGE(2) synthesis [phospholipases (cPLA(2) and sPLA(2)), prostaglandin H synthase (PGHS)-2 and PG E synthases (PGES-1 and -2)] and their relationship to the expression of inflammatory cytokines in samples of myometrium obtained from pregnant women undergoing caesarean section (LSCS) either before or after the onset of labour at or before term; and (ii) the effect of IL-1beta, IL-6, TNF-alpha, PGE(2) and stretch on PGE(2) enzyme mRNA expression. We found that cPLA(2), sPLA(2) and PGHS-2 mRNA expression were greater in labour samples; cPLA(2), sPLA(2), PGHS-2, PGES-1 and -2 mRNA expression were greater in lower- than upper-segment samples; and there was no effect of gestational age. PGHS-2 mRNA levels correlated with those of PGES-1, cPLA(2), IL-1beta and IL-8; PGES-1 mRNA levels correlated with those of IL-1beta, IL-8 and cPLA(2). In primary cultures of uterine myocytes, cPLA(2) mRNA expression was increased by IL-1beta and IL-6; PGHS-2 mRNA expression was increased by IL-1beta, PGE(2) and stretch; and PGES-1 mRNA expression was increased by IL-1beta only. These data show that labour is associated with increased expression of the enzymes involved in PGE(2) synthesis and their expression is greater in the lower uterine segment. The presence of associations between the levels of PGE(2) enzyme mRNA expression and the effects of IL-1beta suggest that their expression is co-ordinated and that IL-1beta is the responsible factor.

Optimization of the medium composition for production of mycelial biomass and exo-polymer by Grifola frondosa GF9801 using response surface methodology

In this work, a three-level Box-Behnken factorial design was employed combining with response surface methodology (RSM) to optimize the medium composition for the production of the mycelial biomass and exo-polymer in submerged cultures by Grifola frondosa GF9801. A mathematical model was then developed to show the effect of each medium composition and their interactions on the production of mycelial biomass and exo-polymer. The model estimated that, a maximal yield of mycelial biomass (17.61 g/l) could be obtained when the concentrations of glucose, KH2PO4, peptone were set at 45.2 g/l, 2.97 g/l, 6.58 g/l, respectively; while a maximal exo-polymer yield (1.326 g/l) could be achieved when setting concentrations of glucose, KH2PO4, peptone at 58.6 g/l, 4.06 g/l and 3.79 g/l, respectively. These predicted values were also verified by validation experiments. Compared with the values obtained by other runs in the experimental design, the optimized medium resulted in a significant increase in the yields of mycelial biomass and exo-polymer. Maximum mycelial biomass yield of 22.50 g/l was achieved in a 15-l fermenter using the optimized medium.

ZnO nanoparticles embedded in sapphire fabricated by ion implantation and annealing

ZnO nanoparticles were fabricated in sapphire (α-Al(2)O(3) single crystal) by Zn ion implantation (48 keV) at an ion fluence of 1 × 10(17) cm(-2) and subsequent thermal annealing in a flowing oxygen atmosphere. Transmission electron microscopy (TEM) analysis revealed that metallic Zn nanoparticles of 3-10 nm in dimensions formed in the as-implanted sample and that ZnO nanoparticles of 10-12 nm in dimensions formed after annealing at 600 °C. A broad absorption band, peaked at 280 nm, appeared in the as-implanted crystal, due to surface plasma resonance (SPR) absorption of metallic Zn nanoparticles. After annealing at 600 °C, ZnO nanoparticles resulted in an exciton absorption peak at 360 nm. The photoluminescence (PL) of the as-implanted sample was very weak when using a He-Cd 325 nm line as the excitation source. However, two emission peaks appeared in the PL spectrum of ZnO nanopraticles, i.e., one ultraviolet (UV) peak at 370 nm and the other a green peak at 500 nm. The emission at 500 nm is stronger and has potential applications in green/blue light-emitting devices.

Design of a Subcutaneous Vascular Access Device Using Ni-Ti SMA Clamps for Hemodialysis

A subcutaneous vascular access device which utilizes an Ni-Ti shape memory alloy (Ni-Ti SMA) spring, has been developed as a new method for subcutaneous vascular access in the treatment of hemodialysis patients. Until now, the connection between the SVAD and needle cannot be externally monitored, and the clamp must be opened and closed with a percutaneous needle by a nephrologist.

The SMA-SVAD accomplishes the opening and closing of its clamp using two Ni-Ti SMA springs, and a transcutaneous energy transmission system (TET) transmits energy to the Ni-Ti SMA springs without the need for percutaneous wires. Two SMA springs open and close the clamp of the SMA-SVAD, without affecting any of the other parts of the system. Wasted thermal energy is reduced to minimal values via electrical regional heating methods. The state of the SMA-SVAD can be monitored according to the amount of power consumed by the external energy transmitter.

In in-vitro experiments, when the clamp was opened and the pressure difference in the hemodialysis machine was set to 50 mmHg, water flow through SMA-SVAD reached 500 ml/min. The maximal surface temperatures of the SVAD and catheter were successfully maintained at proper levels (38~39°C), 2~3 degrees higher than the temperature of the surrounding tissues. The time elapsed from the initiation of energy transmission until the opening of the SMA clamp was 5 seconds.

Dexamethasone Fails to Inhibit the Induction of Cytosolic Phospholipase A2 Expression by Interleukin-1β in Cultured Primary Human Amnion Fibroblasts

OBJECTIVE

To investigate the interaction of dexamethasone and interleukin-1beta (IL-1beta) on the expression of cytosolic phospholipase A(2) (cPLA(2)), the enzyme catalyzing the first reaction in the formation of prostaglandins, in cultured primary human amnion fibroblasts.

DESIGN AND METHODS

Human amnion fibroblasts were prepared from fetal amnion collected at term and were treated with dexamethasone with or without interleukin-1beta for 24h. Prostaglandin E(2) (PGE(2)) output and cPLA(2) expression in cultured amnion fibroblasts were measured with radioimmunoassay, quantitative real-time polymerase chain reaction, Western blotting and cPLA(2) promoter-driven luciferase reporter gene activity.

RESULTS

Both dexamethasone and IL-1beta caused a significant increase in prostaglandin E(2) output, cPLA(2) mRNA and protein expression in cultured human amnion fibroblasts. Both dexamethasone and IL-1beta stimulated cPLA(2) promoter-driven luciferase reporter gene activity. There was no obvious antagonistic or synergistic effect of combined treatment of dexamethasone and IL-1beta on PGE(2) output, cPLA(2) expression or cPLA(2) promoter-driven luciferase reporter gene activity in cultured human amnion fibroblasts.

CONCLUSION

The above findings suggest that paradoxically dexamethasone is a stimulator for both prostaglandin synthesis and cPLA(2) expression in human amnion fibroblasts. The interaction between dexamethasone and IL-1beta on prostaglandin synthesis and cPLA(2) expression is neither synergistic nor conventionally antagonistic.

Association between arterial stiffness and the deformability of red blood cells (RBCs)

The relationship between the flexibility of atherosclerotic vessels and RBC deformability has been investigated. A significant difference of RBC deformability was found among the arterial stiffness groups classified by oscillometric measurement of blood pressure. The deformability was determined by direct microscopic observation of RBCs subjected to shear stress of 0.3 to 40.0 Pa with a rotating rheoscope. The deformability of stiffen group - abnormal pulse wave pattern group or moderate cardiovascular risk group - was found to be much higher than that of normal groups in wide shear stress region (3.0, 10.0, 30.0, and 40.0 Pa). We postulate that the body adapts high shear stress in vivo by making RBCs more distensible, and therefore less likely to rupture under strain or microcirculatory alterations.

A novel sulphur glycoside from the seeds of Descurainia sophia (L.)

A new sulphur glycoside, named descurainoside (1), and the known compound sinapic acid (2) have been isolated from the seeds of Descurainia sophia (L.) Webb ex Prantl. The structure of 1 has been identified as (1R,6S,8R,9S,10S)-9,10-dihydroxy-4-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-8-(hydroxymethyl)-2,7-dioxa-5-thiabicyclo[4.4.0]decan-3-one by means of physico-chemical properties and spectroscopic methods (1D and 2D NMR, HRMS, ESI-MS).

The effects of pulsatile versus non-pulsatile extracorporeal circulation on the pattern of coronary artery blood flow during cardiac arrest

BACKGROUND

In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile versus non-pulsatile circulation to coronary artery flow and myocardial preservation in a cardiac arrest condition.

METHODS

A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25-35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the systemic arterial and coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of <0.05.

RESULTS

The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p<0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p<0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p<0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the systemic and coronary sinus blood (p=NS).

CONCLUSION

In the cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

The 825C/T polymorphism of G-protein beta3 subunit gene and risk of ischaemic stroke

In this study, we investigated the association of G protein beta3 subunit gene (GNB 3) C825T polymorphism with ischaemic stroke and its subtypes in the Chinese Han population in a large case-control study. A total of 990 ischemic stroke patients and 1124 controls were recruited from six medical centres in China. Genotype was determined by polymerase chain reaction and restriction fragment length polymorphism (RFLP) assay. Logistic regression analysis was performed to identify the independent risk factors for stroke. The frequency of 825T carriers is significantly higher in cerebral thrombosis in male subjects (OR=1.35, 95% CI, 1.01-1.82, P=0.046). After further adjustment with traditional risk factors to stroke, the association is not significant. In conclusion, the GNB3 825T allele is not an independent risk factor to ischaemic stroke in the Chinese population.

Percutaneous closure of perimembranous ventricular septal defects with the eccentric Amplatzer device: multicenter follow-up study

Using an Amplatzer membranous eccentric occluder, 186 patients with an average weight of 43.5 kg (range 12.5-77) underwent attempted catheter closure of a perimembranous venricular septal defect (PMVSD). Their age ranged from 3 to 51 years, with the an average age being 15.9 years. The patients were divided into three groups according to morphology of PMVSD: 106 patients with single PMVSD, 63 patients with single PMVSD with aneurysmatic formation, and 17 patients with multiple VSD with aneurysmatic formation. Using angiography, PMVSDs were measured to be between 2.5 and 12 mm, with an average of 5.1 mm. In the third group of patients, we did not measure the size of PMVSD and a device was selected according to the size of entry to the aneurysm. The device was successfully implanted in all patients. The immediate closure rate was 90% in the first group, increasing to 100% at 1 month and remained at that level during follow-up. The immediate closure rate in the second group was 98% and remained the same during follow-up. The immediate closure rate in the third group was 89% and during 1 year of follow-up remained the same. There was no clinical evidence of hemolysis and no incidence of device embolization or bacterial endocarditis after implantation. Before the procedure, all patients showed normal electrocardiogram (ECG) or left ventricle enlargement. After the procedure (at least 3 months later) ECG showed left anterior hemiblock (LAH) in nine patients, complete right bundle branch block in eight patients, and incomplete right bundle branch block in seven patients. A complete heart block (CHB) developed in 2 patients after the procedure (1.07%). The first patient developed LAH immediately after closure and CHB within 24 hours, The heart rate was 28 beats per minute. After treatment with steroids and atropine, CHB changed to sinus rhythm with LAH within 2 months. One year later, the ECG revealed the same findings. The second patient developed CHB immediately after the procedure and was on temporary pacing for 1 week. After 1 month, the patient recovered to sinus rhythm and ECG showed LAH.

Body-centered-cubic Ni and its magnetic properties

The body-centered-cubic (bcc) phase of Ni, which does not exist in nature, has been achieved as a thin film on GaAs(001) at 170 K via molecular beam epitaxy. The bcc Ni is ferromagnetic with a Curie temperature of 456 K and possesses a magnetic moment of 0.52+/-0.08 micro(B)/atom. The cubic magnetocrystalline anisotropy of bcc Ni is determined to be +4.0x10(5) ergs x cm(-3), as opposed to -5.7x10(4) ergs x cm(-3) for the naturally occurring face-centered-cubic (fcc) Ni. This sharp contrast in the magnetic anisotropy is attributed to the different electronic band structures between bcc Ni and fcc Ni, which are determined using angle-resolved photoemission with synchrotron radiation.