bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety and Efficacy of a Fish-Oil–Based Fat Emulsion in the Treatment of Parenteral Nutrition–Associated Liver Disease
Authors: Gura Kathleen M. , Lee Sang , Valim Clarissa , Zhou Jing , Kim Sendia , Modi Biren P. , Arsenault Danielle A. , Strijbosch Robbert A. M. , Lopes Suzanne , Duggan Christopher , Puder Mark
Published: February 2008

BACKGROUND. Parenteral nutrition–associated liver disease can be a progressive and fatal entity in children with short-bowel syndrome. Soybean-fat emulsions provided as part of standard parenteral nutrition may contribute to its pathophysiology.

METHODS. We compared safety and efficacy outcomes of a fish-oil–based fat emulsion in 18 infants with short-bowel syndrome who developed cholestasis (serum direct bilirubin level of >2 mg/dL) while receiving soybean emulsions with those from a historical cohort of 21 infants with short-bowel syndrome who also developed cholestasis while receiving soybean emulsions. The primary end point was time to reversal of cholestasis (3 consecutive measurements of serum direct bilirubin level of ≤2 mg/dL).

RESULTS. Among survivors, the median time to reversal of cholestasis was 9.4 and 44.1 weeks in the fish-oil and historical cohorts, respectively. Subjects who received fish-oil–based emulsion experienced reversal of cholestasis 4.8 times faster than those who received soybean emulsions and 6.8 times faster in analysis adjusted for baseline bilirubin concentration, gestational age, and the diagnosis of necrotizing enterocolitis. A total of 2 deaths and 0 liver transplantations were recorded in the fish-oil cohort and 7 deaths and 2 transplantations in the historical cohort. The provision of fish-oil–based fat emulsion was not associated with essential fatty acid deficiency, hypertriglyceridemia, coagulopathy, infections, or growth delay.

CONCLUSIONS. Parenteral fish-oil–based fat emulsions are safe and may be effective in the treatment of parenteral nutrition–associated liver disease.
Health Supervision for Children With Neurofibromatosis
Authors: Hersh Joseph H. ,   Committee on Genetics
Published: February 2008

Neurofibromatosis 1 is a multisystem disorder that primarily involves the skin and nervous system. Its population prevalence is 1 in 3500. The condition usually is recognized in early childhood, when cutaneous manifestations are apparent. Although neurofibromatosis 1 is associated with marked clinical variability, most affected children do well from the standpoint of their growth and development. Some features of neurofibromatosis 1 are present at birth, and others are age-related abnormalities of tissue proliferation, which necessitate periodic monitoring to address ongoing health and developmental needs and to minimize the risk of serious medical complications. This clinical report provides a review of the clinical criteria needed to establish a diagnosis, the inheritance pattern of neurofibromatosis 1, its major clinical and developmental manifestations, and guidelines for monitoring and providing intervention to maximize the growth, development, and health of an affected child.
Optical absorption spectrum of single-walled carbon nanotubes dispersed in sodium cholate and sodium dodecyl sulfate
Authors: Singh Inderpreet , Bhatnagar P.K. , Mathur P.C. , Bharadwaj L.M.
Published: February 2008

Commercially procured single-walled carbon nanotubes were dispersed in 2 wt% solution of sodium cholate and also in 1 wt% solution of sodium dodecyl sulfate. The absorption spectrum of the suspensions was studied in ultraviolet–visible–near-infrared (UV–vis–NIR) range. Two distinct bands, each containing three peaks, were observed in NIR range for both the suspensions. These peaks correspond to transitions between van Hove singularities E11 and E22 in the density of states of the semiconducting nanotubes. Comparing positions of the observed peaks with the empirical Kataura plot, the diameters and chiralities of the nanotubes were estimated. Using tight binding approximations, the diameter of the nanotubes was also estimated theoretically. Discrepancies between the theoretically calculated diameters and those obtained by empirical Kataura plots are found to be higher for E11 peaks. It has been suggested that the reason for this discrepancy is that the observed E11 peaks are blue-shifted due to Coulomb interactions and exciton formation.
Effect of carbon content on thermal stability of Ti–Cx–Ny thin films
Authors: Lu Y.H. , Shen Y.G.
Published: February 2008

A series of Ti–Cx–Ny thin films with solid-solution and nanocomposite structures were deposited at 500 °C by reactive, unbalanced, direct-current magnetron sputtering. These films were subsequently vacuum annealed at 600, 700, 800, 900, and 1000 °C for 1 h. The effect of C content on the thermal stability of Ti–Cx–Ny thin films was investigated by way of studying the nanostructure and mechanical behaviors of pre- and postannealed samples using x-ray diffraction, high-resolution transmission electron microscopy, Raman spectroscopy, and microindentation measurements. The result indicated that C content played a great role in the nanostructure of Ti–Cx–Ny thin films. A small amount of C fully dissolved in the TiN lattice and produced SS Ti(N,C) thin films. Nanocomposite nanocrystalline (nc)-Ti(N,C)/amorphous-(C, CNx) thin films were followed to be formed with the incorporation of more C. On the other hand, the addition of C had a positive effect on the structural stability of Ti–Cx–Ny thin films. This effect was further enhanced after the formation of a nanocomposite structure. However, neither C content nor film structure had an effect on the thermal stability of mechanical behaviors. Both microhardness and residual stress were successively decreased with temperature and did not show any temperature retardation. The decrease in hardness values was found to be attributed to a decrease of residual compressive stress because of defect annihilation and an increase in nc size.
Effect of LiYO2 on the synthesis and pressureless sintering of Y2SiO5
Authors: Sun Ziqi , Zhou Yanchun , Li Meishuan
Published: February 2008

Y2SiO5 has potential applications as a high-temperature structural ceramic and environmental/thermal barrier coating. In this work, we synthesized single-phase Y2SiO5 powders utilizing a solid–liquid reaction method with LiYO2 as an additive. The reaction path of the Y2O3/SiO2/LiYO2 mixture with variation in temperatures and the role of the LiYO2 additive on preparation process were investigated in detail. The powders obtained by this method have good sinterability. Through a pressureless sintering process, almost fully dense Y2SiO5 bulk material was achieved with a very high density of 99.7% theoretical.
Epitaxial growth, dielectric response, and microstructure of compositionally graded (Ba,Sr)TiO3 thin films grown on (100) MgO substrates by pulsed laser deposition
Authors: Zhu Xinhua , Zhu Jianmin , Zhou Shunhua , Liu Zhiguo , Ming Naiben , Chan Helen Lai-Wah , Choy Chung-Loong , Wong Kin-hung
Published: February 2008

Compositionally graded (Ba1−xSrx)TiO3 (BST) thin films (with 0.0 ⩽ x ⩽ 0.25) were grown by pulsed laser deposition on the (100)MgO single-crystal substrates covered with a conductive La0.5Sr0.5CoO3 (LSCO) layer as a bottom electrode. Their epitaxial growth, dielectric response, and microstructure were characterized. The epitaxial relationships between the BST, LSCO, and MgO can be determined as [001]BST//[001]LSCO//[001]MgO and (100)BST//(100)LSCO//(100)MgO, from the x-ray diffraction (rocking curve, ϕ scans) and electron-diffraction patterns. Dielectric data showed that the room temperature values of the dielectric constant and dielectric loss of the graded BST films were 630 and 0.017 at 100 kHz, respectively. Cross-sectional transmission electron microscopy (TEM) images reveal that both the BST films and the LSCO bottom electrode grow with a columnar structure, and they have flat interfaces and overall uniform thickness across the entire specimen. Cross-sectional high-resolution TEM images reveal that at the LSCO/MgO(100) interface, an interfacial reaction is not seen, whereas edge-type interfacial dislocations with their extra half-planes residing in the LSCO side are observed with an average interval of 2.20 nm, close to the theoretical value of 2.15 nm. At/near the LSCO/BST interface, the graded BST films grow perfectly and coherently on the LSCO lattice because they have the same type of crystal structure and almost same lattice constants, and no interfacial dislocations are observed. Planar TEM images show that the graded films exhibit granular and/or polyhedral morphologies with an average grain size of 50 nm, and the aligned rectangular-shaped voids were also observed. High-resolution TEM images show that the length sizes of voids vary from 8 to 15 nm, and with width of 5 to 10 nm along the 〈001〉 direction in the (100) plane.
Thermal annealing of amorphous Ti–Si–O thin films
Authors: Hodroj Abbas , Chaix-Pluchery Odette , Audier Marc , Gottlieb Ulrich , Deschanvres Jean-Luc
Published: February 2008

Ti–Si–O thin films were deposited using an aerosol chemical vapor deposition process at atmospheric pressure. The film structure and microstructure were analyzed using several techniques before and after thermal annealing. Diffraction results indicate that the films remain x-ray amorphous after annealing, whereas Fourier transform infrared spectroscopy gives evidence of a phase segregation between amorphous SiO2 and well-crystallized anatase TiO2. Crystallization of anatase TiO2 is also clearly shown in the Raman spectra. Transmission electron microscopy analysis indicates that anatase TiO2 nanograins are embedded in a SiO2 matrix in an alternated SiO2/TiO2 multilayer structure.
An embedded-atom method interatomic potential for Pd–H alloys
Authors: Zhou X.W. , Zimmerman J.A. , Wong B.M. , Hoyt J.J.
Published: February 2008

Palladium hydrides have important applications. However, the complex Pd–H alloy system presents a formidable challenge to developing accurate computational models. In particular, the separation of a Pd–H system to dilute (α) and concentrated (β) phases is a central phenomenon, but the capability of interatomic potentials to display this phase miscibility gap has been lacking. We have extended an existing palladium embedded-atom method potential to construct a new Pd–H embedded-atom method potential by normalizing the elemental embedding energy and electron density functions. The developed Pd–H potential reasonably well predicts the lattice constants, cohesive energies, and elastic constants for palladium, hydrogen, and PdHx phases with a variety of compositions. It ensures the correct hydrogen interstitial sites within the hydrides and predicts the phase miscibility gap. Preliminary molecular dynamics simulations using this potential show the correct phase stability, hydrogen diffusion mechanism, and mechanical response of the Pd–H system.
Universal understanding of direct current transport properties of ReRAM based on a parallel resistance model
Authors: Kinoshita K. , Noshiro H. , Yoshida C. , Sato Y. , Aoki M. , Sugiyama Y.
Published: February 2008

We propose a parallel resistance model (PRM) in which total resistance (Rtotal) is given by the parallel connection of resistance of a filament (Rfila) and that of a film excluding the filament (Rexcl)—that is, 1/Rtotal = 1/Rfila + 1/Rexcl—to understand direct current (dc) electric properties of resistive random-access memory (ReRAM). To prove the validity of this model, the dependence of the resistance on temperature, R(T), and the relative standard deviation (RSD) of RHRS of Pt/NiO/Pt on the area of a top electrode, S, are investigated. It is clarified that both the R(T) and RSD depended on S, and all such dependencies can be explained by the PRM. The fact that Rtotal is decided by the magnitude relation between Rfila and Rexcl makes transport properties S-dependent and hinders the correct understanding of ReRAM. Smaller S is essential to observe the intrinsic transport properties of ReRAM filaments.
Solid-state phase separation in Zr–Y–Al–Co metallic glass
Authors: Park Byung Joo , Sohn Sung Woo , Kim Do Hyang , Jeong Hee Tae , Kim Won Tae
Published: February 2008

The present study shows that the as-melt-spun Zr28Y28Al22Co22 amorphous ribbon undergoes solid-state phase separation into Zr- and Y-rich regions when heated below the glass transition temperature (Tg). Dynamic mechanical measurements show that two types of low-temperature relaxation occur below Tg, and transmission electron microscopy observation confirms the solid-state phase-separated microstructure. The diffusion coefficient of solid-state phase separation is calculated by the measured separation distance.
Indentation variability of natural nanocomposite materials
Authors: Oyen Michelle L. , Ko Ching-Chang
Published: February 2008

Small-scale depth-sensing indentation (nanoindentation) is a popular technique for measuring the mechanical properties of a wide range of materials. Contact mechanics solutions used in data analysis are based on the indentation of a homogeneous half-space, but the experiments are frequently conducted on mineralized biological tissues—biocomposite materials with nanometer-scale features—such as bone and dentin. The current study examines the experimental indentation response of bone across orders of magnitude in contact dimension length-scale, from nanometers to micrometers. Scaling arguments are used to establish the need for nanoscale simulations of mineralized tissue indentation. A finite element model of an inhomogeneous contact problem is developed and used to interpret experimental indentation data on bone and dentin. Both experimental data and modeling results demonstrate a convergence in apparent elastic modulus at increasing contact length-scales. Models results are used to estimate a feature size associated with inhomogeneity of the indentation response; for experiments conducted here the characteristic feature size is found to be substantially larger for bone than for dentin, and in both cases larger than for individual nanometer-scale mineral platelets.
Fabrication of porous magnesium with directional pores through use of hydrogen thermally decomposed from MgH2 powders during unidirectional solidification
Authors: Tane Masakazu , Nakajima Hideo
Published: February 2008

Porous magnesium with directional cylindrical pores (or “lotus-type” porous magnesium) was fabricated through the use of hydrogen decomposed from MgH2 powders during unidirectional solidification. Liquid magnesium was cast into a mold in which MgH2 powders were placed and was unidirectionally solidified, which achieved growth of pores elongated along the direction of solidification. The effect of the amount of the MgH2 powders on the pore structure (porosity, diameter, and number density of pores) and the change in the pore structure along the pore growth direction were clarified. The porosity and number density of pores increase with increasing amount of MgH2 powder, and the average diameter of pores decreases with increasing amount of MgH2 powder. The pore structure changes with the growth of pores along the solidification direction.
Stress corrosion of organosilicate glass films in aqueous environments: Role of pH
Authors: Iacopi F. , Elia C. , Fournier T. , Sinapi F. , Travaly Y.
Published: February 2008

Subcritical cracking of thin glass films caused by stress-corrosion phenomena cannot be neglected when it comes to application and manufacturing processes that involve exposure to aqueous environments. A protocol is introduced to allow for a quantitative study of stress corrosion through channel cracking experiments. By this method, an exponential dependence of the crack propagation rate on the pH of the aqueous environment is revealed. Therefore, this behavior should be accounted for through the use of an appropriate pre-exponential factor in the expression of channel cracking rate. This factor should reflect the reduced crack resistance of the glass film caused by the weakening of the silica bonds behind the crack tip in the aqueous environment. A direct comparison between commercial slurries and reference solutions confirms that the crack resistance is a function of the pH of the ambient.
Antimony-doped tin oxide nanoparticles for conductive polymer nanocomposites
Authors: Kleinjan W.E. , Brokken-Zijp J.C.M. , van de Belt R. , Chen Z. , de With G.
Published: February 2008

Nanoparticles of antimony-doped tin oxide (ATO) were characterized for 0–33.3% Sb doping, both in aqueous dispersion and as dried powder. Antimony is incorporated in the cassiterite SnO2 structure of the ATO nanoparticles (d ≈ 7 nm) up to the highest doping levels, mainly as SbV, but with increasing Sb doping the SbIII content increases. We found adsorption of NH3 at the particle surface and evidence for the incorporation of nitrogen in the crystal lattice of the particles. The total nitrogen content increases with increasing Sb doping of the particles. Compact powder conductivity measurements show an increase in conductivity of ATO powder up to 13% Sb and a small decrease for higher Sb contents. Furthermore, we show that these particles can be used to prepare highly transparent conductive cross-linked ATO/acrylate nanocomposites with a continuous fractal particle network through the polymer matrix and a very low percolation threshold (ϕc ≈ 0.3 vol%).
Hedgehog Serves as a Mitogen and Survival Factor During Embryonic Stem Cell Neurogenesis
Authors: Cai Chunyu , Thorne Jeffrey , Grabel Laura
Published: February 2008

Hedgehog (Hh) signaling is involved in a wide range of important biological activities. Within the vertebrate central nervous system, Sonic Hedgehog (Shh) can act as a morphogen or mitogen that regulates the patterning, proliferation, and survival of neural stem cells (NSCs). However, its role in embryonic stem cell (ESC) neurogenesis has not been explored in detail. We have previously shown that Hh signaling is required for ESC neurogenesis. In order to elucidate the underlying mechanism, we utilized the Sox1-GFP ESC line, which has a green fluorescent protein (GFP) reporter under the control of the Sox1 gene promoter, providing an easy means of detecting NSCs in live cell culture. We show here that ESC differentiation in adherent culture follows the ESC→ primitive ectoderm → neurectoderm transitions observed in vivo. Selective death of the Sox1-GFP-negative cells contributes to the enrichment of Sox1-GFP-positive NSCs. Interestingly, Shh is expressed exclusively by the NSCs themselves and elicits distinct downstream gene expression in Sox1-GFP-positive and -negative cells. Suppression of Hh signaling by antagonist treatment leads to different responses from these two populations as well: increased apoptosis in Sox1-GFP-positive NSCs and decreased proliferation in Sox1-GFP-negative primitive ectoderm cells. Hedgehog agonist treatment, in contrast, inhibits apoptosis and promotes proliferation of Sox1-GFP-positive NSCs. These results suggest that Hh acts as a mitogen and survival factor during early ESC neurogenesis, and evidence is presented to support a novel autocrine mechanism for Hh-mediated effects on NSC survival and proliferation.

Disclosure of potential conflicts of interest is found at the end of this article.
Evolution of the c-kit-Positive Cell Response to Pathological Challenge in the Myocardium
Authors: Fransioli Jenna , Bailey Brandi , Gude Natalie A. , Cottage Christopher T. , Muraski John A. , Emmanuel Gregory , Wu Weitao , Alvarez Roberto , Rubio Marta , Ottolenghi Sergio , Schaefer Erik , Sussman Mark A.
Published: February 2008

Cumulative evidence indicates that myocardium responds to growth or injury by recruitment of stem and/or progenitor cells that participate in repair and regenerative processes. Unequivocal identification of this population has been hampered by lack of reagents or markers specific to the recruited population, leading to controversies regarding the nature of these cells. Use of a transgenic mouse expressing green fluorescent protein driven by the c-kit promoter allows for unambiguous identification of this cell population. Green fluorescent protein (GFP) driven by the c-kit promoter labels a fraction of the c-kit+ cells recognized by antibody labeling for c-kit protein. Expression of GFP by the c-kit promoter and accumulation of GFP-positive cells in the myocardium is relatively high at birth compared with adult and declines between postnatal weeks 1 and 2, which tracks in parallel with expression of c-kit protein and c-kit-positive cells. Acute cardiomyopathic injury by infarction prompts increased expression of both GFP protein and GFP-labeled cells in the region of infarction relative to remote myocardium. Similar increases were observed for c-kit protein and cells with a slightly earlier onset and decline relative to the GFP signal. Cells coexpressing GFP, c-kit, and cardiogenic markers were apparent at 1–2 weeks postinfarction. Cardiac-resident c-kit+ cell cultures derived from the transgenic line express GFP that is diminished in parallel with c-kit by induction of differentiation. The use of genetically engineered mice validates and extends the concept of c-kit+ cells participating in the response to myocardial injury.

Disclosure of potential conflicts of interest is found at the end of this article.
The ovary-mediated FSH attenuation of the LH surge in the rat involves a decreased gonadotroph progesterone receptor (PR) action but not PR expression
Authors: Gordon Ana , Garrido-Gracia José C , Aguilar Rafaela , Bellido Carmina , Velasco Juan A García , Millan Yolanda , Tena-Sempere Manuel , Martín de las Mulas Juana , Sánchez-Criado José E
Published: February 2008

Hyperstimulation of ovarian function with human FSH (hFSH) attenuates the preovulatory surge of LH. These experiments aimed at investigating the mechanism of ovarian-mediated FSH suppression of the progesterone (P4) receptor (PR)-dependent LH surge in the rat. Four-day cycling rats were injected with hFSH, oestradiol benzoate (EB) or vehicle during the dioestrous phase. On pro-oestrus, their pituitaries were studied for PR mRNA and protein expression. Additionally, pro-oestrous pituitaries were incubated in the presence of oestradiol-17β (E2), and primed with P4 and LH-releasing hormone (LHRH), with or without the antiprogestin RU486. After 1 h of incubation, pituitaries were either challenged or not challenged with LHRH. Measured basal and LHRH-stimulated LH secretions and LHRH self-priming were compared with those exhibited by incubated pituitaries on day 4 from ovariectomized (OVX) rats in metoestrus (day 2) injected with hFSH and/or EB on days 2 and 3. The results showed that: i) hFSH lowered the spontaneous LH surge without affecting basal LH and E2 levels, gonadotroph PR-A/PR-B mRNA ratio or immunohistochemical protein expression; ii) incubated pro-oestrous pituitaries from hFSH-treated rats did not respond to P4 or LHRH, and lacked E2-augmenting and LHRH self-priming effects and iii) OVX reversed the inhibitory effects of hFSH on LH secretion. It is concluded that under the influence of hFSH, the ovaries produce a non-steroidal factor which suppresses all PR-dependent events of the LH surge elicited by E2. The action of such a factor seemed to be due to a blockade of gonadotroph PR action rather than to an inhibition of PR expression.
Gastric leptin, but not estrogen and somatostatin, contributes to the elevation of ghrelin mRNA expression level in fasted rats
Authors: Zhao Zheng , Sakata Ichiro , Okubo Yusuke , Koike Kanako , Kangawa Kenji , Sakai Takafumi
Published: February 2008

Ghrelin, an endogenous ligand for the GH secretagog receptor, is predominantly produced in the stomach. It has been reported that endogenous ghrelin levels are increased by fasting and decreased after refeeding. It has also been reported that estrogen upregulates ghrelin expression and production and that somatostatin inhibits ghrelin secretion, whereas leptin has a paradoxical effect. Recently, several studies have shown that estrogen, somatostatin, and leptin are produced in the stomach, but the direct effects of these gastric hormones on ghrelin expression in a fasting state remain obscure. In this study, we examined the mRNA expression levels of gastric ghrelin, aromatase (estrogen synthetase), leptin and somatostatin, and concentrations of stomach leptin and portal vein 17β-estradiol in fasted male rats. After 48 h of fasting, although gastric ghrelin mRNA level was significantly increased, both gastric leptin mRNA level and leptin content were decreased. Further, refeeding of fasted rats resulted in a decrease in ghrelin expression level and an increase in leptin expression level. On the other hand, gastric estrogen and somatostatin levels did not change after fasting. In vitro studies revealed that leptin dose-dependently inhibited ghrelin expression and also inhibited estrogen-stimulated ghrelin expression. Moreover, ghrelin cells were found to be tightly surrounded by leptin cells. RT-PCR analysis clearly showed that long and short forms of the leptin receptor are expressed in the rat stomach. These results strongly suggest that an elevated gastric ghrelin expression level in a fasting state is regulated by attenuated restraint from decreased gastric leptin level.
Obestatin inhibits vasopressin secretion: evidence for a physiological action in the control of fluid homeostasis
Authors: Samson Willis K , Yosten Gina L C , Chang Jaw-Kang , Ferguson Alastair V , White Meghan M
Published: February 2008

Obestatin, a product of post-translational processing of the ghrelin prohormone, has been reported to act in the brain to inhibit thirst. We extended our initial studies on water drinking by examining the effects of obestatin on hypovolemia-induced water and saline drinking and vasopressin release in male rats. Intracerebroventricular administration of obestatin significantly inhibited water, but not saline (0.3 M NaCl) drinking in response to a hypovolemic challenge. Obestatin also inhibited, in a dose-related fashion, dehydration-induced vasopressin secretion without affecting plasma oxytocin levels. Vasopressin release induced by central angiotensin II administration was attenuated significantly by prior administration of obestatin. Finally, central administration of an antiserum specific to obestatin resulted in an exaggerated basal vasopressin release and an increased vasopressin response to overnight water deprivation. Antiserum treatment also resulted in significantly increased ad libitum water drinking and drinking in response to dehydration. We conclude that this product of post-translational processing of the ghrelin prohormone may be an important contributor to the physiologic regulation of fluid and electrolyte homeostasis.
Simvastatin antagonizes tumor necrosis factor-α inhibition of bone morphogenetic proteins-2-induced osteoblast differentiation by regulating Smad signaling and Ras/Rho-mitogen-activated protein kinase pathway
Authors: Yamashita Misuzu , Otsuka Fumio , Mukai Tomoyuki , Otani Hiroyuki , Inagaki Kenichi , Miyoshi Tomoko , Goto Junko , Yamamura Masahiro , Makino Hirofumi
Published: February 2008

Recent studies have shown that the mevalonate pathway plays an important role in skeletal metabolism. Statins stimulate bone morphogenetic proteins-2 (BMP-2) production in osteoblasts, implicating a possible beneficial role for statins in promoting anabolic effects on bone. Here, we investigated the effects of a lipophilic simvastatin on osteoblast differentiation using mouse myoblast C2C12 cells, in the presence of tumor necrosis factor-α (TNF-α), an inflammatory cytokine that inhibits osteogenesis. The addition of TNF-α to C2C12 cells suppressed the BMP-2-induced expression of key osteoblastic markers including Runx2 and alkaline phosphatase (ALP) activity. Simvastatin had no independent effects on Runx2 and alkaline phosphatase activity; however, it reversed the suppressive effects of TNF-α. The ability of simvastatin to reverse TNF-α inhibition of BMP-induced Smad1,5,8 phosphorylation and Id-1 promoter activity suggests the involvement of Smad signaling pathway in simvastatin action. In addition, cDNA array analysis revealed that simvastatin increased expression levels of Smads in C2C12 cells exposed to TNF-α that also activated mitogen-activated protein kinase (MAPK) signaling pathways, including extracellular signal-regulated kinase 1/2 (ERK1/2), P38, and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Simvastatin potently suppressed TNF-α-induced phosphorylation of ERK1/2 and SAPK/JNK by inhibiting TNF-α-induced membrane localization of Ras and RhoA. Farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) reversed the simvastatin effects on TNF-α-induced activation of Ras/Rho/MAPK pathways. FPP and GGPP also restored the simvastatin effects on TNF-α-induced suppression of Runx2 and ALP activity. In addition, simvastatin decreased the expression levels of TNF type-1 and -2 receptor mRNAs. Collectively, simvastatin supports BMP-induced osteoblast differentiation through antagonizing TNF-α-to-Ras/Rho/MAPK pathway and augmenting BMP-Smad signaling, suggesting a potential usage of statins to ameliorate inflammatory bone damage.
A population of mammary epithelial cells do not require hormones or growth factors to survive
Authors: Brennan Amelia J , Sharp Julie A , Khalil Elie , Digby Matthew R , Mailer Sonia L , Lefèvre Christophe M , Nicholas Kevin R
Published: February 2008

Hormonal stimulation of mammary explants mimics many of the biochemical changes observed during lactogenesis. Previous studies using eutherian species conclude that mammary explants require addition of exogenous macromolecules to remain hormone responsive in culture. The present study examines the survival of mammary explants from the wallaby and mouse using milk protein gene expression as a functional marker of lactation and cell viability. Mammary explants from pregnant tammars and mice showed that milk protein gene expression was significantly elevated after 3 days of culture with lactogenic hormones. The subsequent removal of exogenous hormones from the media for 10 days resulted in the down-regulation of milk protein genes. Surprisingly, mammary explants remained hormone responsive and expression of milk protein genes was re-induced after a second challenge with lactogenic hormones. Furthermore, the alveolar architecture was maintained. Global functional microarray analysis showed that classic involution markers were not differentially expressed, although two stress-induced survival genes were significantly up-regulated. We report that a population of mammary epithelial cells have an intrinsic capacity to remain viable and hormone responsive for extended periods in chemically defined media without any exogenous macromolecules. We propose that the mammary explant culture model uncouples the first phase of involution, as milk accumulation that normally provides involution stimuli is absent in this culture model allowing a population of cells to survive.
Trends in Perinatal HIV Prevention in New York City, 1994–2003
Authors: Peters Vicki B. , Liu Kai-Lih , Robinson Lisa-Gaye , Dominguez Kenneth L. , Abrams Elaine J. , Gill Balwant S. , Thomas Pauline A.
Published: February 2008

Objectives. We examined trends in perinatal HIV prevention interventions in New York City implemented during 1994 to 2003 to ascertain the success of the interventions in reducing perinatal transmission.

Methods. We used data obtained from infant records at 22 hospitals. We used multiple logistic regression to analyze factors associated with prenatal care and perinatal HIV transmission.

Results. We analyzed data for 4729 perinatally HIV-exposed singleton births. Of mothers with prenatal care data, 92% had prenatal care. The overall proportion who received prenatal care and were diagnosed with HIV before delivery was 86% in 1994 to 1996 and 90% in 1997 to 2003. Use of prenatal antiretrovirals among mothers who received prenatal care was 63% in 1994 to 1996 and 82% in 1997 to 2003. From 1994 to 2003, cesarean births among the entire sample increased from 15% to 55%. During 1997 to 2003, the perinatal HIV transmission rate among the entire sample was 7%; 45% of mothers of infected infants had missed opportunities for perinatal HIV prevention. During 1997 to 2003, maternal illicit drug use was significantly associated with lack of prenatal care. Lack of prenatal, intrapartum, and neonatal antiretrovirals; maternal illicit drug use; and low birthweight were significantly associated with perinatal HIV transmission.

Conclusions. Interventions for perinatal HIV prevention can successfully decrease HIV transmission rates. Ongoing perinatal HIV surveillance allows for monitoring the implementation of guidelines to prevent mother-to-child transmission of HIV and determining factors that may contribute to perinatal HIV transmission.
County Variation in Children's and Adolescent's Health Status and School District Performance in California
Authors: Stone Susan I. , Jung Sunyoung
Published: February 2008

Objectives. We examined the association between county-level estimates of children's health status and school district performance in California.

Methods. We used 3 data sources: the California Health Interview Survey, district archives from the California Department of Education, and census-based estimates of county demographic characteristics. We used logistic regression to estimate whether a school district's failure to meet adequate yearly progress goals in 2004 to 2005 was a function of child and adolescent's health status. Models included district- and county-level fixed effects and were adjusted for the clustering of districts within counties.

Results. County-level changes in children's and adolescent's health status decreased the likelihood that a school district would fail to meet adequate yearly progress goals during the investigation period. Health status did not moderate the relatively poor performance of predominantly minority districts.

Conclusions. We found empirical support that area variation in children's and adolescent's health status exerts a contextual effect on school district performance. Future research should explore the specific mechanisms through which area-level child health influences school and district achievement.
Initial examination of microwave pretreatment on primary, secondary and mixed sludges before and after anaerobic digestion
Authors: Eskicioglu C. , Kennedy K. J. , Droste R. L.
Published: February 2008

The effects of microwave pretreatment on disintegration and mesophilic digestion of waste activated sludge (WAS), primary sludge (PS), combined (PS + WAS) sequencing batch reactor (SBR) sludge and anaerobically digested biocake were investigated by both household and bench scale industrial types microwaves at temperatures below and above boiling point. Pretreatment variables, temperature, intensity (cooking rate) and sludge concentration had statistically significant effects on solubilization. The microwave pretreatment also increased the bioavailability of sludge components under batch anaerobic digestion and enhanced the dewaterability of pretreated sludges after digestion. However, the level of improvements in solubilization and biodegradation from different waste sludges were different. While the largest improvement in ultimate biodegradation was observed in WAS, microwave irradiation only affected the rate of biodegradation of pretreated PS samples. Similarly, relatively lower solubilization ratios achieved for combined - SBR sludge was attributed to high sludge age of extended aeration SBR unit. It is possible that initial sludge characteristics may influence final pretreatment outcomes so that general statements of performance cannot always be made.
Impact of polymer-sludge interaction on rheogram peaks and optimum dose determination
Authors: Murray Audrey , Örmeci Banu
Published: February 2008

Torque rheometry offers potential for in-line monitoring use, screening polymers, and on site optimization of polymer dose by treatment plant operators. This study investigates the peaks formed following direct polymer injection into sludge during rheological analysis. The peaks enable observation of both flocculation and deflocculation phases, and the highest point of the peaks indicates the point where network bonds rupture. The goal of this study was to test the method reported by Örmeci on anaerobically digested sludge samples with several polymers, covering a wide spectrum of molecular weights and cationic charges, to establish a better understanding of how polymer-sludge interaction affects torque-time rheograms and peaks observed after polymer injection. The results from this study indicate that peaks can potentially be used to select the best performing polymer and identify the optimum polymer dose. In the underdose region, the peaks increase in size with increasing polymer dose until the optimum dose is reached. Once the optimum dose is reached, the peaks may decrease in size and then increase again, or stay same size until the polymer dose is very high. In the overdose region, very large and erratic peaks are observed which can be explained by the presence of unmixed polymer in the sample.
Chemical states of trace elements in sewage sludge incineration ash by using x-ray absorption fine structure
Authors: Takaoka M. , Yamamoto T. , Fujiwara S. , Oshita K. , Takeda N. , Tanaka T. , Uruga T.
Published: February 2008

In this study, the chemical states of chromium (Cr), arsenic (As), and selenium (Se) in sewage sludge incineration ash were determined by X-ray absorption fine structure (XAFS) spectroscopy. Sewage sludge incineration ash was sampled from several facilities, and XAFS measurements were carried out with a beam line BL01B1 at the SPring-8 facility. Cr K-edge X-ray absorption near-edge structure (XANES) spectra suggested that Cr compounds were predominantly speciated as Cr(III) and the fraction of Cr(VI) was very minor. Compared to the reference materials, Cr XANES spectra of the incineration ashes were similar to those of FeCr2O4, Cr(OH)3, and CaCr2O4. As K-edge XANES spectra indicated that As(V) compounds were present in incineration ashes. Because the chemical state of As in sewage sludge was As3 +  in our previous study, we speculated that the chemical state of As changed into As(V) during the incineration process. According to Se K-edge XANES spectra, Se compounds were predominantly Se(IV), and a slight difference was observed in the chemical states amongst facilities using inorganic or organic coagulants in the dewatering process.
Optimization of Fe2 + /solids content ratio for a novel sludge heavy metal bioleaching process
Authors: Wong J. W. C. , Gu X. Y.
Published: February 2008

A novel bioleaching process, preincubation bioleaching (PB) has been recently developed in our laboratory for decontamination of heavy-metal-laden sewage sludge by removing the toxic low molecular weight organic acids using an isolated degradative yeast species. The objective of the present study was to optimize Fe2 + /solids content ratio required for removing heavy metals from sewage sludge by using this novel process at high solids content. Results from the present study showed that regardless of the Fe2 + /solids content ratio iron oxidation and sludge acidification could be achieved within 2 days confirming the effectiveness of PB in reducing the inhibitory organic acids. When PB was conducted at an elevated solids content of 3%, Fe2 + /solids content ratio could be reduced to 0.75:1, 1:1 and 1.25:1 for solubilization of Zn, Cu and Cr respectively. Under this optimized bioleaching conditions, the following solubilization efficiencies were obtained after 8 days of bioleaching: 100% Zn, 96% Cu, 60% Cr with no reduction in nutrient contents. Hence, bioleaching at elevated solids contents represents a more economical way for decontamination of heavy-metal-laden sewage sludge while preserving its fertility values.
Evaluating limiting steps of anaerobic degradation of food waste based on methane production tests
Authors: Ortega Luis , Husser Céline , Barrington Suzelle , Guiot Serge R.
Published: February 2008

This research adapted a batch test for biochemical methane production (BMP) to follow the degradation of complex compounds such as proteins and vegetable oils. The test measured the transformation of albumin and olive oil into methane under mesophilic and thermophilic conditions and assess limiting step in the overall degradation process. The thermophilic sludge used for the BMP tests was adapted during ten month from mesophilic sludge while being fed food waste. As compared to acetic acid, the specific rate of transformation of albumin and olive oil into methane reached 22 and 51%, respectively, under mesophilic conditions. Acetoclastic methanogenesis was not the limiting step in the presence of albumin or olive oil (and its monomer-like molecules such as amino acids, glycerol and oleic acid). Rather, the degradation of albumin was restricted by the presence of proteins. The thermophilically adapted sludge showed good proteolytic activity, but its acetoclastic methanogens were unable to degrade olive oil, because of the inhibitory effect of oleic acid.
Adapting UASB technology for sewage treatment in Palestine and Jordan
Authors: Mahmoud Nidal , Zeeman Grietje , van Lier JulesB.
Published: February 2008

High rate anaerobic technologies offer cost-effective solutions for “sewage” treatment in the temperate climate of Palestine and Jordan. However, local sewage characteristics demand amendments to the conventional UASB reactor design. A solution is found in a parallel operating digester unit that stabilises incoming solids and enriches the UASB sludge bed with methanogenic activity. The digester operational conditions were assessed by operating eight CSTRs fed with primary sludge. The results showed a high degree of sludge stabilization in the parallel digesters at SRTs≥10 and 15 days at process temperatures of 35 and 25°C, respectively. The technical feasibility of the UASB-digester combination was demonstrated by continuous flow pilot-scale experiments. A pilot UASB reactor was operated for 81 days at 6 hours HRT and 15°C and was fed with raw domestic sewage. This period was subsequently followed by an 83 day operation period incorporating a parallel digester unit, which was operated at 35°C. The UASB-digester combination achieved removal efficiencies of total, suspended, colloidal and dissolved CODs of respectively 66, 87, 44 and 30%. Preliminary model calculations indicated that a total reactor volume of the UASB-digester system corresponding to 8.6 hours HRT might suffice for sewage treatment in Palestine.
Strategies for chemical cleaning in large scale membrane bioreactors
Authors: Brepols C. , Drensla K. , Janot A. , Trimborn M. , Engelhardt N.
Published: February 2008

Systematically testing alternative cleaning agents and cleaning procedures on a large scale municipal membrane bioreactor, the Erftverband optimized the cleaning strategies and refined the original cleaning procedures for the hollow fiber membranes in use. A time-consuming, intensive ex-situ membrane cleaning twice a year was initially the regular routine. By introducing the effective means of cleaning in place in use today, which employs several acidic and oxidative/alkaline cleaning steps, intensive membrane cleaning could be delayed for years. An overview and an assessment of various cleaning strategies for large scale plants are given.
Effect of Chlorhexidine Application on Microtensile Bond Strength to Dentin
Authors: Soares C. J. , Pereira C. A. , Pereira J. C. , Santana F. R. , Prado C. J.
Published: February 2008

Clinical Relevance

Based on the results of this study, the application of chlorhexidine solution at a concentration of 0.12 and 2% before, after or associated with phosphoric acid etching, presented similar behavior with no adverse effect on 24-hour bond strength.
Class I Gap-formation in Highly-viscous Glass-ionomer Restorations: Delayed vs Immediate Polishing
Authors: Irie M. , Maruo Y. , Nishgawa G. , Suzuki K. , Watts D. C.
Published: February 2008

Clinical Relevance

Delaying polishing for one day resulted in improved gap-formation for Class I restoration of highly-viscous conventional and conventional glass-ionomer cements
Direct Fiber-reinforced Composite Restoration in an Endodontically-treated Molar: A Three-year Case Report
Authors: Deliperi S.
Published: February 2008

Clinical Relevance

The proper utilization of fiber-reinforced resin composite restorations in endodontically-treated molars may preclude the use of more extensive restorative treatment, possibly delaying the need for expensive indirect restorations.
Chemical, Physical, and Genetic Factors Interfering with DNA Repair-a Review
Authors: Bernheim Naomi Jean , Falk Hans
Published: February 2008

Because of its function as transmitter of genetic information, DNA is the most important macromolecule in need of protection from attack by chemical and physical agents, but mechanisms have evolved for repairing such damage to DNA. The presence of the adaptive response and other cellular repair systems (excision, post-replication, SOS, etc.) diminishes the toxicologic effects of low doses of toxic or muta-genic substances. Whether or not these genotoxic effects can be reduced to undetectable levels is not certain. Nonetheless, this repair-mediated diminution of damage due to chemicals constitutes one of the arguments in favor of existence of “safe” threshold levels of chemical exposure (Schendel, 1981).

In turn, the repair process itself may be affected by chemical and physical agents. To determine the mode of action of a specific compound on the process of DNA repair becomes complex when all factors are taken into consideration. There are agents which interfere with DNA repair but they are also as active or more active in suppressing replicative DNA synthesis, as well as RNA and protein synthesis. The interference with repair may arise from other major processes such as alteration of energy metabolism and effects on precursor pathways and/or enzymatic cofactors. Whether or not an agent can specifically inhibit DNA repair enzymes has not been answered. The point must be made, however, that this type of interference with essential protective mechanisms is taking place and it may change anticipated outcomes of chemical or physical exposures. The magnitude of this effect due to the exposure of people to so many chemicals should be recognized and studied for their degree of interference with all the processes of DNA repair.
Importance of Threshold in Safety Assessment of Food Additives, Significance of Animal Pathology Observations
Authors: Wagner Bernard M.
Published: February 2008

The safety of food additives in the human food supply is determined by a variety of methods. Toxicity evaluation in animals requires the same concerns applied to drugs. Aspar-tame and xylitol are used to demonstrate the importance of host threshold in the induction of pathology. Host threshold is largely determined by genetics, species, sex and age. Metabolic processing of food additives, consonant with survival, depends on chemical structure, concentration, route of administration and duration of exposure. When the host threshold is exceeded, a metabolic overload exists straining all homeostatic mechanisms leading eventually to a pathological state. The significance of these pathological conditions in the absence of understanding the underlying mechanisms is open to question in terms of human risk.