bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic Kidney Disease Stage Progression in Liver Transplant Recipients
Authors: LaMattina John C. , Foley David P. , Mezrich Joshua D. , Fernandez Luis A. , Vidyasagar Vijay , D'Alessandro Anthony M. , Musat Alexandru I. , Samaniego-Picota Milagros D. , Pascual Julio , Alejandro Munoz D.R. , Leverson Glen E. , Pirsch John D. , Djamali Arjang
Published: July 2011

Background and objectives

There is little information on chronic kidney disease (CKD) stage progression rates and outcomes in liver transplant recipients. Identifying modifiable risk factors may help prevent CKD progression in liver transplant recipients.

Design, setting, participants, & measurements

We performed a retrospective review of 1151 adult, deceased-donor, single-organ primary liver transplants between July 1984 and December 2007 and analyzed kidney outcomes and risk factors for CKD stage progression. Seven hundred twenty-nine patients had an available estimated GFR at 1 year posttransplant to establish a baseline stage. The primary end point was the CKD progression from one stage to a higher stage (lower GFR).

Results

Kaplan–Meier estimates of patient survival were 91%, 74%, and 64% at 5, 10, and 15 years, respectively. Estimates of liver allograft survival were 89%, 71%, and 60% at the same time points. At 1 year, 7%, 34%, 56%, 3%, and 1% of patients were in CKD stages 1, 2, 3, 4, and 5. The incidence of stage progression was 28%, 40%, and 53% at 3, 5, and 10 years. The incidence of ESRD was 2.6%, 7.5%, and 18% at 5, 10, and 20 years. Multivariable Cox regression analyses demonstrated that CKD stage at 1 year, pretransplant diabetes and urinary tract infections/hypercholesterolemia in the first year proved to be independent risk factors for stage progression (hazard ratio 1.9, 0.28, 1.39, and 1.46, respectively, P < 0.05).

Conclusions

Future studies will determine whether treatment of risk factors in the first posttransplant year prevent CKD progression in liver transplant recipients.
Chronic Kidney Disease Awareness Among Individuals with Clinical Markers of Kidney Dysfunction
Authors: Tuot Delphine S. , Plantinga Laura C. , Hsu Chi-yuan , Jordan Regina , Burrows Nilka Ríos , Hedgeman Elizabeth , Yee Jerry , Saran Rajiv , Powe Neil R.
Published: July 2011

Background and objectives

Awareness of chronic kidney disease (CKD) among providers and patients is low. Whether clinical cues prompt recognition of CKD is unknown. We examined whether markers of kidney disease that should trigger CKD recognition among providers are associated with higher individual CKD awareness.

Design, setting, participants, & measurements

CKD awareness was assessed in 1852 adults with an estimated GFR <60 ml/min per 1.73 m2 using 1999 to 2008 National Health and Nutrition Examination Survey data. CKD awareness was a “yes” answer to “Have you ever been told you have weak or failing kidneys?” Participants were grouped by distribution of the following abnormal markers of CKD: hyperkalemia, acidosis, hyperphosphatemia, elevated blood urea nitrogen, anemia, albuminuria, and uncontrolled hypertension. Odds of CKD awareness associated with each abnormal marker and groupings of markers were estimated by multivariable logistic regression.

Results

Among individuals with kidney disease, only those with albuminuria had greater odds of CKD awareness (adjusted odds ratio, 4.0, P < 0.01) than those without. Odds of CKD awareness increased with each additional manifested clinical marker of CKD (adjusted odds ratio, 1.3, P = 0.05). Nonetheless, 90% of individuals with two to four markers of CKD and 84% of individuals with ≥5 markers of CKD were unaware of their disease.

Conclusions

Although individuals who manifest many markers of kidney dysfunction are more likely to be aware of their CKD, their CKD awareness remains low. A better understanding of mechanisms of awareness is required to facilitate earlier detection of CKD and implement therapy to minimize associated complications.
Survival Trends of US Dialysis Patients with Heart Failure
Authors: Stack Austin G. , Mohammed Amir , Hanley Alan , Mutwali Arif , Nguyen Hoang
Published: July 2011

Background and objectives

Congestive heart failure (CHF) is a major risk factor for death in end-stage kidney disease; however, data on prevalence and survival trends are limited. The objective of this study was to determine the prevalence and mortality effect of CHF in successive incident dialysis cohorts.

Design, setting, participants, & measurements

This was a population-based cohort of incident US dialysis patients (n = 926,298) from 1995 to 2005. Age- and gender-specific prevalence of CHF was determined by incident year, whereas temporal trends in mortality were compared using multivariable Cox regression.

Results

The prevalence of CHF was significantly higher in women than men and in older than younger patients, but it did not change over time in men (range 28% to 33%) or women (range 33% to 36%). From 1995 to 2005, incident death rates decreased for younger men (≤70 years) and increased for older men (>70 years). For women, the pattern was similar but less impressive. During this period, the adjusted mortality risks (relative risk [RR]) from CHF decreased in men (from RR = 1.06 95% Confidence intervals (CI) 1.02–1.11 in 1995 to 0.91 95% CI 0.87–0.96 in 2005) and women (from RR = 1.06 95% CI 1.01–1.10 in 1995 to 0.90 95% CI 0.85–0.95 in 2005 compared with referent year 2000; RR = 1.00). The reduction in mortality over time was greater for younger than older patients (20% to 30% versus 5% to 10% decrease per decade).

Conclusions

Although CHF remains a common condition at dialysis initiation, mortality risks in US patients have declined from 1995 to 2005.
Effects of Antiproteinuric Intervention on Elevated Connective Tissue Growth Factor (CTGF/CCN-2) Plasma and Urine Levels in Nondiabetic Nephropathy
Authors: Slagman Maartje C.J. , Nguyen Tri Q. , Waanders Femke , Vogt Liffert , Hemmelder Marc H. , Laverman Gozewijn D. , Goldschmeding Roel , Navis Gerjan
Published: July 2011

Background and objectives

Connective Tissue Growth Factor (CTGF/CCN-2) is a key player in fibrosis. Plasma CTGF levels predict end-stage renal disease and mortality in diabetic chronic kidney disease (CKD), supporting roles in intra- and extrarenal fibrosis. Few data are available on CTGF in nondiabetic CKD. We investigated CTGF levels and effects of antiproteinuric interventions in nondiabetic proteinuric CKD.

Design, setting, participants, & measurements

In a crossover randomized controlled trial, 33 nondiabetic CKD patients (3.2 [2.5 to 4.0] g/24 h proteinuria) were treated during 6-week periods with placebo, ARB (100 mg/d losartan), and ARB plus diuretics (100 mg/d losartan plus 25 mg/d hydrochlorothiazide) combined with consecutively regular and low sodium diets (193 ± 62 versus 93 ± 52 mmol Na+/d).

Results

CTGF was elevated in plasma (464 [387 to 556] pmol/L) and urine (205 [135 to 311] pmol/24 h) of patients compared with healthy controls (n = 21; 96 [86 to 108] pmol/L and 73 [55 to 98] pmol/24 h). Urinary CTGF was lowered by antiproteinuric intervention, in proportion to the reduction of proteinuria, with normalization during triple therapy (CTGF 99 [67 to 146] in CKD versus 73 [55 to 98] pmol/24 h in controls). In contrast, plasma CTGF was not affected.

Conclusions

Urinary and plasma CTGF are elevated in nondiabetic CKD. Only urinary CTGF is normalized by antiproteinuric intervention, consistent with amelioration of tubular dysfunction. The lack of effect on plasma CTGF suggests that its driving force might be independent of proteinuria and that short-term antiproteinuric interventions are not sufficient to correct the systemic profibrotic state in CKD.
The Microvasculature in Chronic Kidney Disease
Authors: Ooi Qi Lun , Tow Foong Kien Newk-Fon Hey , Deva Raj , Alias Mohamad Afzal , Kawasaki Ryo , Wong Tien Y. , Mohamad Nor , Colville Deb , Hutchinson Anastasia , Savige Judy
Published: July 2011

Background and objectives

Individuals with chronic kidney disease (CKD) stages 3 to 5 have an increased risk of cardiac and other vascular disease. Here we examined the association of CKD 3 to 5 with small vessel caliber.

Design, setting, participants, & measurements

This was a cross-sectional observational study of 126 patients with CKD stages 3 to 5 (estimated GFR [eGFR] <60 ml/min per 1.73 m2) and 126 age- and gender-matched hospital patients with CKD 1 or 2. Retinal vessel diameters were measured from digital fundus images by a trained grader using a computer-assisted method and summarized as the central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE).

Results

Patients with CKD 3 to 5 had a smaller mean CRAE and CRVE than hospital controls (139.4 ± 17.8 μm versus 148.5 ± 16.0 μm, P < 0.001; and 205.0 ± 30.7 μm versus 217.4 ± 25.8 μm, respectively; P = 0.001). CRAE and CRVE decreased progressively with each stage of renal failure CKD1–2 to 5 (P for trend = 0.08 and 0.04, respectively). CKD and hypertension were independent determinants of arteriolar narrowing after adjusting for age, gender, diabetes, dyslipidemia, and smoking history. Patients with CKD 5 and diabetes had a larger mean CRAE and CRVE than nondiabetics (141.4 ± 14.9 μm versus 132.9 ± 14.2 μm; 211.1 ± 34.4 μm versus 194.8 ± 23.8 μm).

Conclusions

The microvasculature is narrowed in patients with reduced eGFR.
Kidney Function Reference Values in US Adolescents
Authors: Chavers Blanche M. , Rheault Michelle N. , Foley Robert N.
Published: July 2011

Background and objectives

Few data are available on kidney function in normal US adolescents. This study characterizes the distribution of kidney function measures and associated factors.

Design, setting, participants, & measurements

Serum creatinine, cystatin C, and urinary albumin-to-creatinine ratios were measured in US adolescents (aged 12 to 17 years;n= 5575) in the cross-sectional National Health and Nutrition Examination Survey 1999–2008. The reference population was defined as healthy adolescents with BP <120/80 mmHg and a Z-score for weight-to-height ≤1.645, without self-reported diabetes or hypertension, not using prescription medications in the preceding 30 days, not pregnant or currently menstruating. Results were analyzed by age, gender, race, ethnicity, body mass index, and BP; estimated GFR (eGFR) was calculated using the original and revised Schwartz formulas.

Results

Mean values for eGFRSchwartz original formula, serum creatinine, and serum cystatin C were 147 ml/min/1.73 m2, 0.71 mg/dl, 0.82 mg/L, respectively. The median urinary albumin-to-creatinine ratio was 6.8 mg/g creatinine. In the reference population (n= 2881), eGFR differed significantly using the two Schwartz formulas; values were higher using the original formula (median values 143versus96 ml/min/1.73 m2). Serum creatinine level (0.7versus0.72 mg/dl), but not cystatin C level (0.82versus0.82 mg/L), was lower in the reference population than in a nonreference population of adolescents.

Conclusions

These findings provide important demographic information and highlight the need for confirmatory testing of the revised Schwartz formula by comparison to measured GFR in healthy US adolescents.
Vision-Threatening Retinal Abnormalities in Chronic Kidney Disease Stages 3 to 5
Authors: Deva Rajeev , Alias Mohamad Afzal , Colville Deb , Tow Foong Kien Newk-Fon Hey , Ooi Qi Lun , Chew Sky , Mohamad Nor , Hutchinson Anastasia , Koukouras Ignatios , Power David A. , Savige Judith
Published: July 2011

Background and objectives

Retinal abnormalities are common in inherited and acquired renal disease. This study determined the prevalence of retinal abnormalities in chronic kidney disease (CKD) stages 3 to 5.

Design, setting, participants, & measurements

One hundred fifty patients with CKD stages 3 to 5 and 150 age- and gender-matched hospital patients with CKD stages 1 to 2 underwent bilateral retinal photography. These images were reviewed for incidental abnormalities, microvascular (Wong and Mitchell classification) and diabetic retinopathy (Airlie House criteria), and macular degeneration (Seddon classification).

Results

Three (2%) patients with CKD stages 3 to 5 had retinal features characteristic of inherited renal disease (atrophy in Myopathy, Encephalopathy, Lactic Acidosis, Stroke-like episodes [MELAS] syndrome; and 2 with drusen in dense deposit disease). Fifty-nine (39%) patients had moderate-severe microvascular retinopathy (hemorrhages, exudates, etc.) compared with 19 (13%) with CKD stages 1 to 2. Forty-one (28%) had moderate-severe diabetic retinopathy (microaneurysms, exudates, etc.) compared with 16 (11%) with CKD stages 1 to 2. Ten (7%) had severe macular degeneration (geographic atrophy, hemorrhage, exudates, membranes) compared with one (1%) with CKD stages 1 to 2. Renal failure was an independent risk factor for microvascular retinopathy, diabetic retinopathy, and macular degeneration. Eleven (7.3%) patients with renal failure and one (0.7%) with CKD stages 1 to 2 had previously unrecognized vision-threatening retinal abnormalities that required immediate ophthalmologic attention.

Conclusions

Retinal abnormalities are common in CKD stages 3 to 5, and are more severe and more likely to threaten vision than in hospital patients with CKD stages 1 to 2.
Insights from the Chronic Kidney Disease in Children (CKiD) Study
Authors: Copelovitch Lawrence , Warady Bradley A. , Furth Susan L.
Published: July 2011

Over the last 5 years, the Chronic Kidney Disease in Children (CKiD) prospective cohort study has enrolled close to 600 children ages 1 to 16 years with mild to moderate chronic kidney disease (CKD). The main purpose of this interim report is to review the initial cross-sectional data and conclusions derived from the clinical studies conducted within CKiD in the context of findings from other pediatric CKD and end-stage renal disease (ESRD) registry and cohort studies. In particular, special emphasis was placed on studying four aspects of chronic kidney disease in children, including the identification of risk factors related to disease progression, the impact of CKD on neurocognition and quality of life (QoL), the cardiovascular morbidity associated with CKD, and identifying the causes and effects of growth failure in the context of mild to moderate kidney failure.
A Randomized Study of Allopurinol on Endothelial Function and Estimated Glomular Filtration Rate in Asymptomatic Hyperuricemic Subjects with Normal Renal Function
Authors: Kanbay Mehmet , Huddam Bulent , Azak Alper , Solak Yalcin , Kadioglu Gulay Kocak , Kirbas Ismail , Duranay Murat , Covic Adrian , Johnson Richard J.
Published: July 2011

Background and objectives

Endothelial dysfunction is an early manifestation of vascular injury and contributes to the development of atherosclerotic cardiovascular disease. Recent studies have implicated hyperuricemia as a risk factor for cardiovascular disease. We hypothesized that lowering uric acid in subjects with asymptomatic hyperuricemia with allopurinol might improve endothelial dysfunction, BP, estimated GFR (eGFR), and inflammatory markers.

Design, setting, participants, & measurements

Subjects with asymptomatic hyperuricemia and no history of gout and 30 normouricemic control subjects were enrolled in this 4-month randomized prospective study. Thirty hyperuricemic patients received 300 mg/d allopurinol and were compared with 37 hyperuricemic patients and 30 normouricemic subjects in matched control groups. Flow-mediated dilation (FMD), eGFR, ambulatory BP monitoring, spot urine protein-creatine ratio, and highly sensitive C-reactive protein were measured at baseline and at 4 months.

Results

Age, gender, lipid profile, eGFR, hemoglobin, glucose, and level of proteinuria were similar in hyperuricemic subjects and controls at baseline. As expected, hyperuricemic patients had higher levels of highly sensitive C-reactive protein and lower FMD compared with normouricemic patients. Allopurinol treatment resulted in a decrease in serum uric acid, a decrease in systolic BP, an increase in FMD, and an increase in eGFR compared with baseline. No significant difference was observed in the control hyperuricemic and normouricemic groups. In a multiple regression analysis, FMD levels were independently related to uric acid both before (beta = −0.55) and after (beta = −0.40) treatment.

Conclusions

Treatment of hyperuricemia with allopurinol improves endothelial dysfunction and eGFR in subjects with asymptomatic hyperuricemia.
Trace detection of inorganic oxidants using desorption electrospray ionization (DESI) mass spectrometry
Authors: Sokol Ewa , Jackson Ayanna , Cooks R.
Published: July 2011

Desorption electrospray ionization (DESI), an established ambient ionization method in mass spectrometry (MS) for the analysis of organic compounds, is applied here to trace detection of inorganic salts, including inorganic oxidants. In-situ surface analysis of targeted compounds, including nitrogen-, halogen- and sulfur-salts, down to sub-nanogram levels, was performed using DESI-MS. Successful experiments were carried out in both the negative and the positive ion modes; simple anions and cations as well as small cluster ions were observed. Various surfaces are examined and surface porosity effects were briefly explored. Absolute detection limits on porous polytetrafluoroethylene (PTFE) of 120 pg (surface concentration 0.07 ng mm−2) and 50 pg (surface concentration 0.03 ng mm−2), were achieved for sodium chlorate and sodium perchlorate, respectively. The compounds of interest were examined in the presence of a hydrocarbon mixture to assess matrix effects: only a two- or three-fold decrease in the target ion intensity was observed. Commercial fireworks were analyzed to determine perchlorate salts in complex mixtures. This work demonstrates the potential applicability of ambient ionization mass spectrometry to forensic investigations involving improvised explosives.
Analysis of crystallographic and structural data of polymeric FeM (M = transition metals, lanthanides) complexes
Authors: Melnik Milan , Garaj Ján
Published: July 2011

This review covers crystallographic and structural data for almost fifty polymeric FeM complexes (M = transition Cu, Ag, Au, Mo, W, Mn, Co, Ni and Pt and lanthanide elements Sm, Er and Yb) where iron is involved in polymeric chains. The complexes are for the most part yellow or black, but there are complexes of brown, orange, red, purple, blue and green colour. The complexes crystallized in the monoclinic (by far prevails), triclinic, tetragonal, orthorhombic, trigonal, hexagonal and rhombohedral crystal classes. The iron atoms are found in oxidation states 0, +2 and +3, of which +3 by far prevails. The inner coordination spheres about the Fe(0) atom are tetrahedral (FeC4) or sandwiched (FeC10), Fe(II) atoms are six-coordinated, and Fe(III) are six or even seven-coordinated. The inner coordination about M atoms range from four- through six- to eight-coordinated. The shortest Fe-Fe, Fe-M (transition) and Fe-M (lanthanide) and M-M separations are: 8.08 Å, 3.033 Å for Fe-Cu, 3.010 Å for Fe-Yb and 2.505 Å for Mo-Mo.
A prospect for LiBH4 as on-board hydrogen storage
Authors: Saldan Ivan
Published: July 2011

In contrast to the traditional metal hydrides, in which hydrogen storage involves the reversible hydrogen entering/exiting of the host hydride lattice, LiBH4 releases hydrogen via decomposition that produces segregated LiH and amorphous B phases. This is obviously the reason why lithium borohydride applications in fuel cells so far meet only one requirement — high hydrogen storage capacity. Nevertheless, its thermodynamics and kinetics studies are very active today and efficient ways to meet fuel cell requirements might be done through lowering the temperature for hydrogenation/dehydrogenation and suitable catalyst. Some improvements are expected to enable LiBH4 to be used in on-board hydrogen storage.
Osmium assay in fixatives and stained rat tissues by means of acid and o,o′-dihydroxo substituted monoazo dyes and some flavonoids
Authors: Rydchuk Mariana , Mykhalyna Galyna , Dobryanska Olga , Korkuna Olha , Vrublevska Teodoziya
Published: July 2011

New simple, rapid and accurate spectrophotometric techniques for osmium assays in fixatives and stained tissues have been elaborated using acid (Tropaeolin O, Tropaeolin OOO-I, Tropaeolin OOO-II, Orange G), o,o′-dihydroxo substituted azo dyes (Eriochrome Blue Black R, Acid Chrome Dark-Blue, Eriochrome Black T) and flavonoids (morin, quercetin, luteolin). Methods are based on sensitive osmium(IV) reactions with reagents and the formation of stable coloured compounds. Tolerance ratios of main matrix components of histological specimens during Os(IV) spectrophotometric determination with reagents has been established. Results of osmium determination in fixatives and fixed tissues, obtained by means of different reagents, appeared to be sufficiently similar, although effects of matrix components differ. The accuracy of spectrophotometric osmium assay in fixatives with azo dyes has been confirmed with voltammetric investigations. Results obtained from osmium uptake by rat gum tissues are valuable for clinical testing of dental drugs, indicating the influence of drug treatment on the gums.
Non-magnetic impurity doping effect on the magnetic state of p-type Al-doped delafossite oxide CuCrO2
Authors: Jlaiel Fatma , Amami Mongi , Strobel Piere , Salah Abdelhamid
Published: July 2011

We investigated the substitution effects of Al3+ for Cr3+ on the structure and magnetic, properties of delafossite oxide CuCrO2, which possesses a quasi-2D Heisenberg triangular antiferromagnetic (AFM) lattice. The lattice parameters was found to vary according to the Vegard’s rule. We also found that the large local lattice distortion, caused by the nonmagnetic dopant with different radii between magnetic and nonmagnetic ions, affects the samples significantly. Magnetization and specific heat measurements indicated that AFM ordering is diluted by the substitution of nonmagnetic Al3+ for Cr3+ (S = 3/2).
Determination of 137Cs and 85Sr transport parameters in fucoidic sand columns and groundwater system
Authors: Palágyi Štefan , Štamberg Karel
Published: July 2011

The determination is based on the evaluation of experimentally obtained breakthrough curves using the erfc-function. The first method is founded on the assumption of a reversible linear sorption/desorption isotherm of radionuclides on solid phase with constant distribution and retardation coefficients, whereas the second one is based on the assumption of a reversible non-linear sorption/desorption isotherm described with the Freundlich equation, i.e., with non-constant distribution and retardation coefficients. Undisturbed cores of 5 cm in diameter and 10 cm long were embedded in the Eprosin-type cured epoxide resin column. In this study the so-called Cenomanian background groundwater was used as transport medium. The groundwater containing radionuclides was introduced at the bottom of the columns at about 4 mL h−1 constant flow-rate. The results have shown that in the investigated fucoidic sands: (i) the sorption was in principle characterized by linear isotherms and the corresponding retardation coefficients of 137Cs and 85Sr, depending on the type of sample, were approximately 13 or 44 and 5 or 15, respectively; (ii) the desorption was characterized by non-linear isotherms, and the retardation coefficients of the same radionuclides ranged between 23–50 and 5–25, respectively. The values of the hydrodynamic dispersion coefficients of these radionuclides varied between 0.43–1.2 cm2 h−1.
Ion chromatographic method for the determination of cations of group IA and IIA in water samples, pharmaceuticals and energy drinks by non-suppressed conductometric detection
Authors: Zachariadis George , Lyratzi Anastasia , Stratis John
Published: July 2011

An efficient ion chromatographic (IC) method was developed for the simultaneous quantitative determination of Li+, Na+, NH4+, K+, Cs+, Ca2+, Mg2+, Sr2+, Ba2+ and Be2+ in energy drinks, pharmaceutical and drinking water samples by non-suppressed conductometric detection. The separation of ten cations including ammonium was achieved using a cation-exchange column and low conductivity mobile phase. The mobile phase consisted of tartaric acid, dipicolinic acid and boric acid. The separation of the cations was completed in less than 18 min, with a flow rate of 1.2 mL min−1. The separation was not affected by the existence of cations Co2+, Cr3+, Cd2+, Cu2+, Bi3+, Ag+, Fe3+ and Zn2+ in concentrations up to 20 mg L−1. Using an injection volume of 20 μL the obtained detection limits were 0.003 mg L−1, 0.02 mg L−1, 0.01 mg L−1, 0.01 mg L−1, 0.10 mg L−1, 0.01 mg L−1, 0.02 mg L−1, 0.02 mg L−1, 0.003 mg L−1 and 0.1 mg L−1, for Li+, Na+, NH4+, K+, Cs+, Ca2+, Mg2+, Sr2+, Be2+ and Ba2+ respectively. The intra-day repeatability (RSD%, n=5) ranged from 1.1% to 4.8%, and the inter-day (n=5) between 1.8% and 5.4% respectively. The method was applied to the analysis of various bottled and tap water, pharmaceutical preparations and energy drinks commercially available.
Influence of activated carbon modifications on their catalytic activity in methanol and ethanol conversion reactions
Authors: Jasińska Jadwiga , Krzyżyńska Beata , Kozłowski Mieczysław
Published: July 2011

Activated carbons containing different surface functionalities have been investigated as catalysts in conversion reactions of ethanol and methanol. These carbon materials were prepared from Polish brown coal by chemical activation with potassium hydroxide and modified by the oxidation or reaction with ammonia or chlorine. The main process upon ethanol decomposition was its dehydrogenation, while in the process of methanol decomposition only a few samples were catalytically active, and the only product was dimethyl ether (a product of dehydration).
Adsorption properties of a nanostructured hybrid material containing aluminium towards some metal ions
Authors: Detcheva Albena , Vassileva Paunka , Georgieva Ralitsa , Voykova Dimitrinka , Gerganova Tsvetelina , Ivanova Yordanka
Published: July 2011

In the present work the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium was investigated. The novel organic-inorganic material was synthesized via a sol-gel method through hydrolysis and co-condensation reactions. Its structure was characterized by means of SEM, XRD and FTIR. Based on the data obtained the most probable cross-linking mechanism for the derived xerogel was proposed. The characterization of its texture parameters was carried out by low-temperature adsorption of nitrogen. The adsorption properties of this material with respect to Cu(II), Cr(III) and Pb(II) ions from single-component aqueous solutions and multi-component aqueous solutions containing also Cd(II) and Fe(III) were evaluated. The effect of contact time, acidity of initial solutions and metal ion concentrations was investigated using the batch method. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. In all cases the adsorption was significantly affected by the pH value. Equilibrium modelling data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models. Best fit was observed for Langmuir model, which showed determination coefficients greater than 0.992 for all ions studied. The maximum adsorption capacities for single- and multi-component adsorption were calculated.
Nanoporous carbon — metal composites for hydrogen storage
Authors: Giasafaki Dimitra , Bourlinos Athanassios , Charalambopoulou Georgia , Stubos Athanassios , Steriotis Theodore
Published: July 2011

Metal-carbon composites have shown considerable hydrogen storage potential at room temperature. In the present work the behaviour of two different Pd amalgam doped carbon substrates, namely a carbogenic foam and a mildly oxidised ordered mesoporous carbon, are compared on the basis of their hydrogen sorption properties at 77 and 298 K and low pressures, aiming to investigate the effect of surface on the storage capacity. In both cases, the introduction of alloy nanoparticles leads to an improvement of the hydrogen uptake with respect to pure carbons. This effect is significant for the carbogenic foam however small for the ordered carbon.
Intramolecular N to N acyl migration in conformationally mobile 1′-acyl-1-benzyl-3′,4′-dihydro-1′H-spiro[piperidine-4,2′-quinoline] systems promoted by debenzylation conditions (HCOONH4/Pd/C)
Authors: Méndez Leonor , Kouznetsov Vladimir
Published: July 2011

We report an efficient and useful synthesis of new attractive spiropiperdine scaffolds 4 based on an intramolecular acyl transfer process in 1′-acyl-1-benzyl-3′,4′-dihydro-1′H-spiro[piperidine-4,2′-quinolines] 3 using simple and mild debenzylation reaction conditions (HCOONH4/Pd/C). The compounds 3 were prepared by acylating 1-benzyl-4′-methyl-3′,4′-dihydro-1′H-spiro[piperidine-4,2′-quinolines] 2 that are easily available from 1-benzyl-4-piperidone 1. The intramolecular character of this process was proven primarily through a crossover experiment technique. Through an examination of all spectroscopic information (1H, 13C NMR, VT-1H NMR, and 2D NMR) it was possible to correctly predict amide configurations and piperidine ring conformations of starting and final spiropiperidine compounds.
Intervening in Alienation
Authors: Taines Cynthia
Published: July 2011

This article investigates whether school activism diminishes the alienation that accompanies urban youths’ observations of unequal educational conditions, and often leads to underachievement and school rejection. The study is based on interviews with 13 urban youth about their participation in a community-based program that supports education organizing. Findings reveal that school activism is a promising intervention that encourages more constructive responses to schooling. However, the opportunity to participate in school activism was more influential for students who were already integrated into school life and initially felt less acutely alienated. Implications for enhancing the prevalence of success among urban students are considered.
L'ombre révélatrice. Caricature, personnification, allégorie
Authors: Guédron Martial
Published: July 2011

Dans la tradition académique, l’allégorie est définie comme une sélection d’objets qui servent à représenter autre chose que ce qu’ils sont en effet. Or si une telle définition évoque d’abord d’ambitieuses compositions à clés, on peut aussi la rapporter à l’un des stratagèmes les plus fréquents de la caricature. Il en est ainsi lorsque, jouant sur des détails incongrus, le caricaturiste signale un sens caché tout en le rendant assez lisible pour que sa compréhension s’impose au spectateur. C’est ce processus qui est à l’œuvre dans le motif étudié ici : l’altération de l’ombre portée d’un personnage comme moyen de révéler sa part obscure. Dans l’utilisation qu’ils en ont faite, Piercy Roberts, Jean-Jacques-Isidore Gérard, dit Grandville et Honoré Daumier témoignent de ce que l’ombre allégorique a souvent un contenu politique et satirique. Avec eux, l’artiste se transforme en montreur d’ombres qui révèle au spectateur la véritable nature, foncièrement mauvaise, des hommes de pouvoir dont l’apparence officielle n’est que tromperie et artifice.
Allégorie et tautologie : la politique du poème, de Baudelaire à Mallarmé
Authors: Monginot Benoît
Published: July 2011

Mallarmé s’oppose à Baudelaire sur une question de poétique. L’allégorie débouche dans ses poèmes sur une mise en relief de la dimension tautologique de tout acte de signification. Nous montrons ici comment cette opposition poétique est un affrontement politique : Mallarmé en redéfinissant l’allégorie redéfinit consciemment les modalités du partage du sens. La pensée de l’allégorie est explicitement chez lui une réflexion sur la communauté, une économie de la violence.
Cytokine-Induced Alterations of α7 Nicotinic Receptor in Colonic CD4 T Cells Mediate Dichotomous Response to Nicotine in Murine Models of Th1/Th17- versus Th2-Mediated Colitis
Authors: Galitovskiy Valentin , Qian Jing , Chernyavsky Alexander I. , Marchenko Steve , Gindi Vivian , Edwards Robert A. , Grando Sergei A.
Published: July 2011

Ulcerative colitis (UC) and Crohn’s disease (CD) are two forms of chronic inflammatory bowel disease. CD4 T cells play a central role in the pathogenesis of both diseases. Smoking affects both UC and CD but with opposite effects, ameliorating UC and worsening CD. We hypothesized that the severity of gut inflammation could be modulated through T cell nicotinic acetylcholine receptors (nAChRs) and that the exact clinical outcome would depend on the repertoire of nAChRs on CD4 T cells mediating each form of colitis. We measured clinical and immunologic outcomes of treating BALB/c mice with oxazolone- and trinitrobenzene sulfonic acid (TNBS)-induced colitides by nicotine. Nicotine attenuated oxazolone colitis, which was associated with an increased percentage of colonic regulatory T cells and a reduction of Th17 cells. TCR stimulation of naive CD4+CD62L+ T cells in the presence of nicotine upregulated expression of Foxp3. In marked contrast, nicotine worsened TNBS colitis, and this was associated with increased Th17 cells among colonic CD4 T cells. Nicotine upregulated IL-10 and inhibited IL-17 production, which could be abolished by exogenous IL-12 that also abolished the nicotine-dependent upregulation of regulatory T cells. The dichotomous action of nicotine resulted from the up- and downregulation of anti-inflammatory α7 nAChR on colonic CD4 T cells induced by cytokines characteristic of the inflammatory milieu in oxazolone (IL-4) and TNBS (IL-12) colitis, respectively. These findings help explain the dichotomous effect of smoking in patients with UC and CD, and they underscore the potential for nicotinergic drugs in regulating colonic inflammation.
Long-Distance Regulation of Fetal Vδ Gene Segment TRDV4 by the Tcrd Enhancer
Authors: Hao Bingtao , Krangel Michael S.
Published: July 2011

Murine Tcra and Tcrd gene segments are organized into a single genetic locus (Tcra/Tcrd locus) that undergoes V(D)J recombination in CD4−CD8− double-negative (DN) thymocytes to assemble Tcrd genes and in CD4+CD8+ double-positive thymocytes to assemble Tcra genes. Recombination events are regulated by two developmental stage-specific enhancers, Eδ and Eα. Effects of Eα on Trca/Tcrd locus chromatin have been well documented, but effects of Eδ have not. In this regard, Eα acts over long distances to activate many Vα and Jα segments for recombination in double-positive thymocytes. However, in DN thymocytes, it is unclear whether Eδ functions over long distances to regulate Vδ gene segments or functions only locally to regulate Dδ and Jδ gene segments. In this study, we analyzed germline transcription, histone modifications, and recombination on wild-type and Eδ-deficient alleles in adult and fetal thymocytes. We found that Eδ functions as a local enhancer whose influence is limited to no more than ∼10 kb in either direction (including Dδ, Jδ, and TRDV5 gene segments) in adult DN thymocytes. However, we identified a unique long-distance role for Eδ promoting accessibility and recombination of fetal Vδ gene segment TRDV4, over a distance of 55 kb, in fetal thymocytes. TRDV4 recombination is specifically repressed in adult thymocytes. We found that this repression is enforced by a developmentally regulated loss of histone acetylation. Constitutively high levels of a suppressive modification, histone H3 lysine 9 dimethylation, may contribute to repression as well.
Chronic Fetal Exposure to Ureaplasma parvum Suppresses Innate Immune Responses in Sheep
Authors: Kallapur Suhas G. , Kramer Boris W. , Knox Christine L. , Berry Clare A. , Collins Jennifer J. P. , Kemp Matthew W. , Nitsos Ilias , Polglase Graeme R. , Robinson James , Hillman Noah H. , Newnham John P. , Chougnet Claire , Jobe Alan H.
Published: July 2011

The chorioamnionitis associated with preterm delivery is often polymicrobial with ureaplasma being the most common isolate. To evaluate interactions between the different proinflammatory mediators, we hypothesized that ureaplasma exposure would increase fetal responsiveness to LPS. Fetal sheep were given intra-amniotic (IA) injections of media (control) or Ureaplasma parvum serovar 3 either 7 or 70 d before preterm delivery. Another group received an IA injection of Escherichia coli LPS 2 d prior to delivery. To test for interactions, IA U. parvum-exposed animals were challenged with IA LPS and delivered 2 d later. All animals were delivered at 124 ± 1-d gestation (term = 150 d). Compared with the 2-d LPS exposure group, the U. parvum 70 d + LPS group had 1) decreased lung pro- and anti-inflammatory cytokine expression and 2) fewer CD3+ T lymphocytes, CCL2+, myeloperoxidase+, and PU.1+ cells in the lung. Interestingly, exposure to U. parvum for 7 d did not change responses to a subsequent IA LPS challenge, and exposure to IA U. parvum alone induced mild lung inflammation. Exposure to U. parvum increased pulmonary TGF-β1 expression but did not change mRNA expression of either the receptor TLR4 or some of the downstream mediators in the lung. Monocytes from fetal blood and lung isolated from U. parvum 70 d + LPS but not U. parvum 7 d + LPS animals had decreased in vitro responsiveness to LPS. These results are consistent with the novel finding of downregulation of LPS responses by chronic but not acute fetal exposures to U. parvum. The findings increase our understanding of how chorioamnionitis-exposed preterm infants may respond to lung injury and postnatal nosocomial infections.
Mycobacterium tuberculosis Triggers Host Type I IFN Signaling To Regulate IL-1β Production in Human Macrophages
Authors: Novikov Aleksey , Cardone Marco , Thompson Robert , Shenderov Kevin , Kirschman Kevin D. , Mayer-Barber Katrin D. , Myers Timothy G. , Rabin Ronald L. , Trinchieri Giorgio , Sher Alan , Feng Carl G.
Published: July 2011

Mycobacterium tuberculosis is a virulent intracellular pathogen that survives in macrophages even in the presence of an intact adaptive immune response. Type I IFNs have been shown to exacerbate tuberculosis in mice and to be associated with disease progression in infected humans. Nevertheless, the mechanisms by which type I IFNs regulate the host response to M. tuberculosis infection are poorly understood. In this study, we show that M. tuberculosis induces an IFN-related gene expression signature in infected primary human macrophages, which is dependent on host type I IFN signaling as well as the mycobacterial virulence factor, region of difference-1. We further demonstrate that type I IFNs selectively limit the production of IL-1β, a critical mediator of immunity to M. tuberculosis. This regulation occurs at the level of IL1B mRNA expression, rather than caspase-1 activation or autocrine IL-1 amplification and appears to be preferentially used by virulent mycobacteria since avirulent M. bovis bacillus Calmette-Guérin (BCG) fails to trigger significant expression of type I IFNs or release of mature IL-1β protein. The latter property is associated with decreased caspase-1–dependent IL-1β maturation in the BCG-infected macrophages. Interestingly, human monocytes in contrast to macrophages produce comparable levels of IL-1β in response to either M. tuberculosis or BCG. Taken together, these findings demonstrate that virulent and avirulent mycobacteria employ distinct pathways for regulating IL-1β production in human macrophages and reveal that in the case of M. tuberculosis infection the induction of type I IFNs is a major mechanism used for this purpose.
Zinc Finger Protein Tristetraprolin Interacts with CCL3 mRNA and Regulates Tissue Inflammation
Authors: Kang Ju-Gyeong , Amar Marcelo J. , Remaley Alan T. , Kwon Jaeyul , Blackshear Perry J. , Wang Ping-yuan , Hwang Paul M.
Published: July 2011

Zinc finger protein tristetraprolin (TTP) modulates macrophage inflammatory activity by destabilizing cytokine mRNAs. In this study, through a screen of TTP-bound mRNAs in activated human macrophages, we have identified CCL3 mRNA as the most abundantly bound TTP target mRNA and have characterized this interaction via conserved AU-rich elements. Compared to the wild-type cells, TTP−/− macrophages produced higher levels of LPS-induced CCL3. In addition, the plasma level of CCL3 in TTP−/− mice was markedly higher than that in wild-type mice. To determine the in vivo significance of TTP-regulated CCL3, we generated CCL3−/−TTP−/− double-knockout mice. Along with decreased proinflammatory cytokines in their paw joints, there were significant functional and histologic improvements in the inflammatory arthritis of TTP−/− mice when CCL3 was absent, although cachexia, reflecting systemic inflammation, was notably unaffected. Furthermore, the marked exacerbation of aortic plaque formation caused by TTP deficiency in the APOE−/− mouse model of atherosclerosis was also rescued by disrupting CCL3. Taken together, our data indicate that the interaction between TTP and CCL3 mRNA plays an important role in modulating localized inflammatory processes in tissues that are dissociated from the systemic manifestations of chronic inflammation.
Growth, structure and optical characterization of Al‐doped ZnO nanoparticle thin films
Authors: Prajapati C. S. , Sahay P. P.
Published: July 2011

Al‐doped ZnO nanoparticle thin films were prepared on glass substrate at the optimum temperature of (410±10) °C by spray pyrolysis technique using zinc nitrate as a precursor solution and aluminium chloride as a dopant. The dopant concentration (Al/Zn at%) was varied from 0 to 2 at%. Structural analysis of the films shows that all the films are of polycrystalline zinc oxide in nature, possessing hexagonal wurtzite structure. The films exhibit variation in peak intensities corresponding to (100), (002) and (101) reflection planes on Al‐doping. The crystallite size calculated by Scherrer formula has been found to be in the range of 35‐65 nm. The optical absorption study shows that the optical band gap in the Al‐doped films varies in the range of 3.11 – 3.22 eV. The width of localized states in the band gap estimated by the Urbach tail analysis has been found to be minimum in case of the 1 at% Al‐doped zinc oxide thin film. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Iterative frequency‐domain detection and channel estimation for space–time block codes
Authors: Marques da Silva Mário , Dinis Rui
Published: July 2011

In this paper, we consider iterative frequency‐domain receivers for block transmission techniques with rate‐1 space–time block coding (STBC) for two or four transmit antennas. Single carrier with frequency‐domain equalisation (SC‐FDE) combined with antenna diversity is a promising candidate for future broadband wireless systems. Because our STBC with four transmit antennas is not orthogonal, our receiver includes the cancellation of the residual interference, allowing performances close to the ones of an orthogonal code.

We propose an iterative STBC receiver that considers an iterative detection and channel estimation. The channel estimates usually obtained with the help of pilot symbols and/or training sequences are multiplexed with data symbols. Because this leads to spectral degradation, the use of superimposed pilots (i.e. pilots added to data) was recently proposed as an efficient alternative. Our performance results show that the proposed SC‐FDE STBC receiver allows excellent performance with the use of the channel data obtained from the channel estimation. Copyright © 2011 John Wiley & Sons, Ltd.
Mechanics of Homeotropically Ordered Smectic‐A Elastomers with Global Oblate Chain Conformation
Authors: Kramer Dominic , Finkelmann Heino
Published: July 2011

Smectic‐A elastomers combine one‐dimensional translational order of rod‐like segments with the rubber elasticity of a polymer network. In recent years, detailed investigations were carried out on elastomers showing a global prolate chain conformation. In this communication, the first experiments on fluorinated SAelastomers exhibiting a global oblate chain conformation are presented, where the polymer chains are on average compressed along the layer normal of the lamellar phase structure. The mechanical anisotropy is studied by means of thermoelastic experiments and stress–strain measurements. For the first time, the layer compression modulusBof smectic elastomers is directly measured.Bis significantly larger as compared to conventional low molar mass liquid crystals and decreases significantly with increasing local disorder introduced by the isotropic crosslinker.

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Generalized‐Yvon–Born–Green Model of Toluene
Authors: Ellis Christopher R. , Rudzinski Joseph F. , Noid William G.
Published: July 2011

Coarse‐grained (CG) models provide a highly efficient computational means for investigating complex processes that evolve on large length‐scales or long time‐scales. The predictive capability of these models relies upon their ability to reproduce the relevant structural properties of accurate, though prohibitively expensive, atomistic models. The many‐body potential of mean force (PMF) is the appropriate potential for a CG model that quantitatively reproduces the structure of an underlying atomistic model. Because this PMF cannot be readily calculated or simulated, several methods attempt to systematically approximate this PMF with relatively simple molecular mechanics potentials. Recently, we have proposed a generalized‐Yvon–Born–Green (g‐YBG) approach to determine approximate potentials for accurate CG models directly from structural information. In the present work, we demonstrate the mechanism by which the g‐YBG approach employs simple structural information to characterize and approximate the many‐body PMF. We then employ this approach to parameterize a three site CG model for liquid toluene. We demonstrate that this model accurately reproduces the structural properties of an all‐atom model. Moreover, using this model system, we demonstrate the variational nature of the method and investigate the sensitivity of the model to the CG mapping. Finally, we briefly investigate the transferability of the CG model to different temperatures.

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On the optimal control of a linear neutral differential equation arising in economics
Authors: Boucekkine Raouf , Fabbri Giorgio , Pintus Patrick
Published: July 2011

In this paper, we apply two optimization methods to solve an optimal control problem of a linear neutral differential equation (NDE) arising in economics. The first one is a variational method, and the second follows a dynamic programming approach. Because of the infinite dimensionality of the NDE, the second method requires the reformulation of the latter as an ordinary differential equation in an appropriate abstract space. It is shown that the resulting Hamilton–Jacobi–Bellman equation admits a closed‐form solution, allowing for a much finer characterization of the optimal dynamics compared with the alternative variational method. The latter is clearly limited by the nontrivial nature of asymptotic analysis of NDEs. Copyright © 2011 John Wiley & Sons, Ltd.
Co‐optimization of emitter profile and metal grid of selective emitter silicon solar cells
Authors: Wen Zhenli , Zhou Chunlan , Wang Wenjing
Published: July 2011

Co‐optimization of the metallization and emitter dopant profile is fully investigated for selective emitter crystalline silicon solar cells. The simulation parameters for the laser doping selective emitter, metallization by plating, silicon nitride passivation, and aluminum back surface field are identified and reached. Internal light flux reflection is also considered in the model. In particular, the influence of the increased light trapping ability of a textured surface on the optimization results is clarified by comparing a cell with a non‐textured surface. In this paper, the optimization results, including the electrical performances of a solar cell are discussed in detail. On the basis of these simulation results, an optimized metallization and emitter dopant profile is proposed. Copyright © 2011 John Wiley & Sons, Ltd.