bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and functional characterization of a missense mutation in resistin in two patients with severe obesity and insulin resistance
Authors: Beckers Sigri , de Freitas Fenna , Zegers Doreen , Verrijken An , Peeters Armand V , Peiffer Frida , Verhulst Stijn L , Massa Guy , Mertens Ilse L , Desager Kristine N , Van Gaal Luc F , Van Hul Wim
Published: March 2011

Objective

In this study, we hypothesized that mutations in the resistin encoding gene, RETN, may cause a monogenic form of obesity.

Design/methods

We screened the coding region of RETN in 81 morbidly obese adults, 263 overweight and obese children/adolescents, and 116 healthy lean subjects. In vitro experiments include qPCR, ELISA, and western blot for WT and mutant resistin transfected into 3T3-L1 adipocytes.

Results

Mutation analysis identified five sequence variants in our patient populations: 3′-UTR +87 G/A, 3′-UTR +100 A/G, T73T, IV3-61 C/A, and C78S. In our control population, we only found the 3′-UTR +87 G/A variant. We started functional experiments for the C78S mutation that was found in a 20-year-old obese male (body mass index (BMI)=39.7 kg/m2) and his obese mother (BMI=31.9 kg/m2). In vitro testing demonstrated that the mutation does not impair mRNA expression. We identified a 100-fold lower extracellular protein concentration for mutant resistin compared with WT levels using a resistin ELISA on cell culture medium (P=4.87×10−6). We also detected a decreased intracellular concentration for the mutant protein (tenfold lower relative levels, P=0.007). The plasma resistin levels of the proband and his mother, however, did not differ significantly from lean control individuals.

Conclusions

In conclusion, we identified the first missense mutation in resistin in a morbidly obese proband and his obese mother. Functional testing of the mutant protein suggests that the C78S mutant protein is degraded, possibly resulting in a decreased extracellular concentration, which may predispose to obesity.
Phenotypic profiling of parents with cryptic nonclassic congenital adrenal hyperplasia: findings in 145 unrelated families
Authors: Nandagopal Radha , Sinaii Ninet , Avila Nilo A , Van Ryzin Carol , Chen Wuyan , Finkielstain Gabriela P , Mehta Sneha P , McDonnell Nazli B , Merke Deborah P
Published: March 2011

Objective

To comprehensively phenotype parents identified with nonclassic congenital adrenal hyperplasia (NCCAH) by family genetic studies, termed here as cryptic NCCAH and to define the incidence of cryptic NCCAH in the parents of a large cohort of patients with 21-hydroxylase deficiency.

Design

Genotyping was performed on 249 parents of 145 unrelated congenital adrenal hyperplasia (CAH) patients. Parents with two CYP21A2 mutations underwent extensive evaluation.

Results

Of the 249 parents, ten (4%; seven females and three males) were identified as having cryptic NCCAH. The majority was of ethnicities previously reported to have a higher incidence of NCCAH. Cosyntropin stimulation performed in eight parents provided biochemical confirmation (17-hydroxyprogesterone range 56–364 nmol/l) and cortisol response was ≤500 nmol/l in three parents (38%). Of the seven women (27–54 years) with cryptic NCCAH, four had prior infertility, two reported irregular menses, two had treatment for hirsutism, one had androgenic alopecia. Men were asymptomatic. All cryptic NCCAH parents reported normal puberty and had normal height. Adrenal hypertrophy and a small adrenal myelolipoma were observed in two parents; testicular adrenal rest tissue was not found.

Conclusions

Parents diagnosed with NCCAH by genetic testing are mostly asymptomatic. Temporary female infertility and suboptimal cortisol response were commonly observed. Ongoing glucocorticoid therapy is not indicated in adults with CAH identified by family genotype studies unless symptomatic, but glucocorticoid stress coverage should be considered in select cases. Parents of a child with CAH have a 1:25 risk of having NCCAH; if the mother of a child with CAH has infertility, evaluation for NCCAH is indicated.
A Link Between Impaired Purine Nucleotide Synthesis and Apoptosis in Drosophila melanogaster
Authors: Holland Catherine , Lipsett David B , Clark Denise V
Published: March 2011

The biosynthetic pathways and multiple functions of purine nucleotides are well known. However, the pathways that respond to alterations in purine nucleotide synthesis in vivo in an animal model organism have not been identified. We examined the effects of inhibiting purine de novo synthesis in vivo and in cultured cells of Drosophila melanogaster. The purine de novo synthesis gene ade2 encodes phosphoribosylformylglycinamidine synthase (EC 6.3.5.3). An ade2 deletion, generated by P-element transposon excision, causes lethality in early pupal development, with darkening, or necrosis, of leg and wing imaginal disc tissue upon disc eversion. Together with analysis of a previously isolated weaker allele, ade24, and an allele of the Prat gene, which encodes an enzyme for the first step in the pathway, we determined that the lethal arrest and imaginal disc phenotypes involve apoptosis. A transgene expressing the baculovirus caspase inhibitor p35, which suppresses apoptosis caused by other stresses such as DNA damage, suppresses both the imaginal disc tissue darkening and the pupal lethality of all three purine de novo synthesis mutants. Furthermore, we showed the presence of apoptosis at the cellular level in both ade2 and Prat mutants by detecting TUNEL-positive nuclei in wing imaginal discs. Purine de novo synthesis inhibition was also examined in tissue culture by ade2 RNA interference followed by analysis of genome-wide changes in transcript levels. Among the upregulated genes was HtrA2, which encodes an apoptosis effector and is thus a candidate for initiating apoptosis in response to purine depletion.
O-Linked-N-Acetylglucosamine Cycling and Insulin Signaling Are Required for the Glucose Stress Response inCaenorhabditis elegans
Authors: Mondoux Michelle A , Love Dona C , Ghosh Salil K , Fukushige Tetsunari , Bond Michelle , Weerasinghe Gayani R , Hanover John A , Krause Michael W
Published: March 2011

In a variety of organisms, including worms, flies, and mammals, glucose homeostasis is maintained by insulin-like signaling in a robust network of opposing and complementary signaling pathways. The hexosamine signaling pathway, terminating in O-linked-N-acetylglucosamine (O-GlcNAc) cycling, is a key sensor of nutrient status and has been genetically linked to the regulation of insulin signaling in Caenorhabditis elegans. Here we demonstrate that O-GlcNAc cycling and insulin signaling are both essential components of the C. elegans response to glucose stress. A number of insulin-dependent processes were found to be sensitive to glucose stress, including fertility, reproductive timing, and dauer formation, yet each of these differed in their threshold of sensitivity to glucose excess. Our findings suggest that O-GlcNAc cycling and insulin signaling are both required for a robust and adaptable response to glucose stress, but these two pathways show complex and interdependent roles in the maintenance of glucose–insulin homeostasis.
Germline Fitness-Based Scoring of Cancer Mutations
Authors: Fischer Andrej , Greenman Chris , Mustonen Ville
Published: March 2011

A key goal in cancer research is to find the genomic alterations that underlie malignant cells. Genomics has proved successful in identifying somatic variants at a large scale. However, it has become evident that a typical cancer exhibits a heterogenous mutation pattern across samples. Cases where the same alteration is observed repeatedly seem to be the exception rather than the norm. Thus, pinpointing the key alterations (driver mutations) from a background of variations with no direct causal link to cancer (passenger mutations) is difficult. Here we analyze somatic missense mutations from cancer samples and their healthy tissue counterparts (germline mutations) from the viewpoint of germline fitness. We calibrate a scoring system from protein domain alignments to score mutations and their target loci. We show first that this score predicts to a good degree the rate of polymorphism of the observed germline variation. The scoring is then applied to somatic mutations. We show that candidate cancer genes prone to copy number loss harbor mutations with germline fitness effects that are significantly more deleterious than expected by chance. This suggests that missense mutations play a driving role in tumor suppressor genes. Furthermore, these mutations fall preferably onto loci in sequence neighborhoods that are high scoring in terms of germline fitness. In contrast, for somatic mutations in candidate onco genes we do not observe a statistically significant effect. These results help to inform how to exploit germline fitness predictions in discovering new genes and mutations responsible for cancer.
Circumventing Heterozygosity: Sequencing the Amplified Genome of a Single HaploidDrosophila melanogasterEmbryo
Authors: Langley Charles H , Crepeau Marc , Cardeno Charis , Corbett-Detig Russell , Stevens Kristian
Published: March 2011

Heterozygosity is a major challenge to efficient, high-quality genomic assembly and to the full genomic survey of polymorphism and divergence. In Drosophila melanogaster lines derived from equatorial populations are particularly resistant to inbreeding, thus imposing a major barrier to the determination and analyses of genomic variation in natural populations of this model organism. Here we present a simple genome sequencing protocol based on the whole-genome amplification of the gynogenetically derived haploid genome of a progeny of females mated to males homozygous for the recessive male sterile mutation, ms(3)K81. A single “lane” of paired-end sequences (2 × 76 bp) provides a good syntenic assembly with >95% high-quality coverage (more than five reads). The amplification of the genomic DNA moderately inflates the variation in coverage across the euchromatic portion of the genome. It also increases the frequency of chimeric clones. But the low frequency and random genomic distribution of the chimeric clones limits their impact on the final assemblies. This method provides a solid path forward for population genomic sequencing and offers applications to many other systems in which small amounts of genomic DNA have unique experimental relevance.
Modeling of Identity-by-Descent Processes Along a Chromosome Between Haplotypes and Their Genotyped Ancestors
Authors: Druet Tom , Farnir Frederic Paul
Published: March 2011

Identity-by-descent probabilities are important for many applications in genetics. Here we propose a method for modeling the transmission of the haplotypes from the closest genotyped relatives along an entire chromosome. The method relies on a hidden Markov model where hidden states correspond to the set of all possible origins of a haplotype within a given pedigree. Initial state probabilities are estimated from average genetic contribution of each origin to the modeled haplotype while transition probabilities are computed from recombination probabilities and pedigree relationships between the modeled haplotype and the various possible origins. The method was tested on three simulated scenarios based on real data sets from dairy cattle, Arabidopsis thaliana, and maize. The mean identity-by-descent probabilities estimated for the truly inherited parental chromosome ranged from 0.94 to 0.98 according to the design and the marker density. The lowest values were observed in regions close to crossing over or where the method was not able to discriminate between several origins due to their similarity. It is shown that the estimated probabilities were correctly calibrated. For marker imputation (or QTL allele prediction for fine mapping or genomic selection), the method was efficient, with 3.75% allelic imputation error rates on a dairy cattle data set with a low marker density map (1 SNP/Mb). The method should prove useful for situations we are facing now in experimental designs and in plant and animal breeding, where founders are genotyped with relatively high markers densities and last generation(s) genotyped with a lower-density panel.
Insights Into Mutagenesis Using Escherichia coli Chromosomal lacZ Strains That Enable Detection of a Wide Spectrum of Mutational Events
Authors: Seier Tracey , Padgett Dana R , Zilberberg Gal , Sutera Vincent A , Toha Noor , Lovett Susan T
Published: March 2011

Strand misalignments at DNA repeats during replication are implicated in mutational hotspots. To study these events, we have generated strains carrying mutations in the Escherichia coli chromosomal lacZ gene that revert via deletion of a short duplicated sequence or by template switching within imperfect inverted repeat (quasipalindrome, QP) sequences. Using these strains, we demonstrate that mutation of the distal repeat of a quasipalindrome, with respect to replication fork movement, is about 10-fold higher than the proximal repeat, consistent with more common template switching on the leading strand. The leading strand bias was lost in the absence of exonucleases I and VII, suggesting that it results from more efficient suppression of template switching by 3′ exonucleases targeted to the lagging strand. The loss of 3′ exonucleases has no effect on strand misalignment at direct repeats to produce deletion. To compare these events to other mutations, we have reengineered reporters (designed by Cupples and Miller 1989) that detect specific base substitutions or frameshifts in lacZ with the reverting lacZ locus on the chromosome rather than an F′ element. This set allows rapid screening of potential mutagens, environmental conditions, or genetic loci for effects on a broad set of mutational events. We found that hydroxyurea (HU), which depletes dNTP pools, slightly elevated templated mutations at inverted repeats but had no effect on deletions, simple frameshifts, or base substitutions. Mutations in nucleotide diphosphate kinase, ndk, significantly elevated simple mutations but had little effect on the templated class. Zebularine, a cytosine analog, elevated all classes.
Differential Contributions of Histone H3 and H4 Residues to Heterochromatin Structure
Authors: Yu Qun , Olsen Lars , Zhang Xinmin , Boeke Jef D , Bi Xin
Published: March 2011

Transcriptional silencing in Saccharomyces cerevisiae is mediated by heterochromatin. There is a plethora of information regarding the roles of histone residues in transcriptional silencing, but exactly how histone residues contribute to heterochromatin structure is not resolved. We address this question by testing the effects of a series of histone H3 and H4 mutations involving residues in their aminoterminal tails, on the solvent-accessible and lateral surfaces of the nucleosome, and at the interface of the H3/H4 tetramer and H2A/H2B dimer on heterochromatin structure and transcriptional silencing. The general state, stability, and conformational heterogeneity of chromatin are examined with a DNA topology-based assay, and the primary chromatin structure is probed by micrococcal nuclease. We demonstrate that the histone mutations differentially affect heterochromatin. Mutations of lysine 16 of histone H4 (H4-K16) and residues in the LRS (loss of rDNA silencing) domain of nucleosome surface markedly alter heterochromatin structure, supporting the notion that H4-K16 and LRS play key roles in heterochromatin formation. Deletion of the aminoterminal tail of H3 moderately alters heterochromatin structure. Interestingly, a group of mutations in the globular domains of H3 and H4 that abrogate or greatly reduce transcriptional silencing increase the conformational heterogeneity and/or reduce the stability of heterochromatin without affecting its overall structure. Surprisingly, yet another series of mutations abolish or reduce silencing without significantly affecting the structure, stability, or conformational heterogeneity of heterochromatin. Therefore, histone residues may contribute to the structure, stability, conformational heterogeneity, or other yet-to-be-characterized features of heterochromatin important for transcriptional silencing.
Nitrogen Metabolite Repression of Metabolism and Virulence in the Human Fungal Pathogen Cryptococcus neoformans
Authors: Lee I Russel , Chow Eve W L , Morrow Carl A , Djordjevic Julianne T , Fraser James A
Published: March 2011

Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine—three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°–40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection.
Identification of a Role for Histone H2B Ubiquitylation in Noncoding RNA 3′-End Formation Through Mutational Analysis of Rtf1 in Saccharomyces cerevisiae
Authors: Tomson Brett N , Davis Christopher P , Warner Marcie H , Arndt Karen M
Published: March 2011

The conserved eukaryotic Paf1 complex regulates RNA synthesis by RNA polymerase II at multiple levels, including transcript elongation, transcript termination, and chromatin modifications. To better understand the contributions of the Paf1 complex to transcriptional regulation, we generated mutations that alter conserved residues within the Rtf1 subunit of the Saccharomyces cerevisiae Paf1 complex. Importantly, single amino acid substitutions within a region of Rtf1 that is conserved from yeast to humans, which we termed the histone modification domain, resulted in the loss of histone H2B ubiquitylation and impaired histone H3 methylation. Phenotypic analysis of these mutations revealed additional defects in telomeric silencing, transcription elongation, and prevention of cryptic initiation. We also demonstrated that amino acid substitutions within the Rtf1 histone modification domain disrupt 3′-end formation of snoRNA transcripts and identify a previously uncharacterized regulatory role for the histone H2B K123 ubiquitylation mark in this process. Cumulatively, our results reveal functionally important residues in Rtf1, better define the roles of Rtf1 in transcription and histone modification, and provide strong genetic support for the participation of histone modification marks in the termination of noncoding RNAs.
Bone Loss in Adolescents After Bariatric Surgery
Authors: Kaulfers Anne-Marie D. , Bean Judy A. , Inge Thomas H. , Dolan Lawrence M. , Kalkwarf Heidi J.
Published: March 2011

OBJECTIVE:

To evaluate bone loss in adolescents after Roux-en-Y gastric bypass surgery and to determine the extent to which bone loss was related to weight loss. We hypothesized that adolescents would lose bone mass after surgery and that it would be associated with weight loss.

PATIENTS AND METHODS:

We conducted a retrospective case review of 61 adolescents after bariatric surgery. Whole-body bone mineral content (BMC) and density (BMD) were measured by dual-energy radiograph absorptiometry, and age- and gender-specific BMD z scores were calculated. Measurements were obtained when possible before surgery and then every 3 to months after surgery for up to 2 years. Data were analyzed by using a mixed-models approach, and regression models were adjusted for age, gender, and height.

RESULTS:

Whole-body BMC, BMD z score, and weight decreased significantly over time after surgery (P < .0001 for all). In the first 2 years after surgery, predicted values on the basis of regression modeling for BMC decreased by 7.4%, and BMD z score decreased from 1.5 to 0.1. During the first 12 months after surgery, change in weight was correlated with change in BMC (r = 0.31; P = .02). Weight loss accounted for 14% of the decrease in BMC in the first year after surgery.

CONCLUSION:

Bariatric surgery is associated with significant bone loss in adolescents. Although the predicted bone density was appropriate for age 2 years after surgery, longer follow-up is warranted to determine whether bone mass continues to change or stabilizes.
Carbon Dioxide and Glucose Affect Electrocortical Background in Extremely Preterm Infants
Authors: Wikström Sverre , Lundin Fredrik , Ley David , Pupp Ingrid Hansen , Fellman Vineta , Rosén Ingmar , Hellström-Westas Lena
Published: March 2011

OBJECTIVES:

To investigate if Paco2 and plasma glucose levels affect electrocortical activity.

METHODS:

Ours was an observational study of 32 infants with a gestational age of 22 to 27 weeks. We performed simultaneous single-channel electroencephalogram (EEG) and repeated blood gas/plasma glucose analyses during the first 3 days (n = 247 blood samples with corresponding EEG). Interburst intervals (IBIs) and EEG power were averaged at the time of each blood sample.

RESULTS:

There was a linear relationship between Paco2 and IBI; increasing Paco2 was associated with longer IBIs. One day after birth, a 1-kPa increase in Paco2 was associated with a 16% increase in IBI in infants who survived the first week without severe brain injury. EEG power was highest at a Paco2 value of 5.1 kPa and was attenuated both at higher and lower Paco2 values. Corrected for carbon dioxide effects, plasma glucose was also associated with IBI. Lowest IBI appeared at a plasma glucose level of 4.0 mmol/L, and there was a U-shaped relationship between plasma glucose level and EEG with increasing discontinuity at glucose concentrations above and below 4.0 mmol/L.

CONCLUSIONS:

Both carbon dioxide and plasma glucose level influenced EEG activity in extremely preterm infants, and values considered to be within normal physiologic ranges were associated with the best EEG background. Increasing EEG discontinuity occurred at carbon dioxide levels frequently applied in lung-protection strategies; in addition, moderate hyperglycemia was associated with measurable EEG changes. The long-term effects of changes in carbon dioxide and glucose on brain function are not known.
Castleman's Disease: From Basic Mechanisms to Molecular Therapeutics
Authors: El-Osta Hazem E. , Kurzrock Razelle
Published: March 2011

Castleman's disease is a rare lymphoproliferative disorder in which there has been recent progress in elucidating underlying mechanisms with potential therapeutic implications. Unicentric Castleman's disease is an indolent condition that is often treated with local approaches. In contrast, patients with multicentric Castleman's disease (MCD) have a less favorable prognosis and require systemic treatment. Cytotoxic chemotherapy, with its attendant risk for toxicity, has been widely used to treat MCD, with variable efficacy. The discovery of putative etiologic factors and targets in MCD, particularly human herpes virus 8, CD20, and interleukin (IL)-6, has been translated into the use of rituximab and anti–IL-6-based therapy, as well as antiviral agents. In this article, we review the current state of the art of our understanding of Castleman's disease and its treatment and we provide insight into future treatment strategies based on disease biology.
Noncardiac Vascular Toxicities of Vascular Endothelial Growth Factor Inhibitors in Advanced Cancer: A Review
Authors: Keefe Dorothy , Bowen Joanne , Gibson Rachel , Tan Thean , Okera Meena , Stringer Andrea
Published: March 2011

The introduction of molecularly targeted anticancer therapies has brought the promise of longer survival times for select patients with cancers previously considered untreatable. However, it has also brought new toxicities that require understanding and management, sometimes for long periods of time. Vascular endothelial growth factor inhibitors are associated with a broad range of adverse effects, with vascular toxicity being particularly serious. This review focuses on the current understanding of the pathophysiology and mechanisms of macrovascular toxicities (hypertension, hemorrhage, and thromboembolism), their incidence and severity, the current clinical management, and implications in the advanced cancer setting. Movement of these agents into the early disease setting will alter the impact of these toxicities.

Search Strategy and Selection Criteria.

Information for this review was collected by searching PubMed/Medline and American Society of Clinical Oncology abstract databases. The medical subject heading terms used included toxicity, hypertension, thromboembolism, hemorrhage, intestinal perforation, risk factors, pharmacokinetics, and metabolism, combined with free text search terms including, but not limited to, VEGF inhibitor*, bevacizumab, sunitinib, and sorafenib. Articles published in English before March 2010 were included, in addition to information from case reports and pharmaceutical agent package inserts.
Bevacizumab Treatment to Progression After Chemotherapy: Outcomes from a U.S. Community Practice Network
Authors: Nadler Eric , Yu Elaine , Ravelo Arliene , Sing Amy , Forsyth Michael , Gruschkus Stephen
Published: March 2011

Bevacizumab significantly extends progression-free survival (PFS) and overall survival (OS) times when combined with initial chemotherapy and continued as monotherapy until disease progression or unacceptable toxicity in patients with nonsquamous non-small cell lung cancer (NSCLC). In clinical practice, bevacizumab is sometimes discontinued after completion of chemotherapy. This retrospective analysis of the US Oncology network's electronic medical records evaluated the association between PFS and OS times and bevacizumab monotherapy to progression (BTP) among patients with advanced NSCLC.

Patients treated from July 2006 through June 2008 were analyzed as two cohorts based on whether or not they received BTP after completion of first-line chemotherapy plus bevacizumab. Hazard ratios for PFS and OS were estimated using Cox proportional hazards, adjusting for relevant treatment and patient characteristics. To account for survivorship bias, landmark analyses were conducted at 18, 21, and 26 weeks from initial therapy to examine residual PFS and OS times, defined as the time from the landmark to disease progression or death.

From the total 498 nonsquamous NSCLC patients, 403 received first-line chemotherapy plus bevacizumab: 154 received BTP, 249 did not. Longer PFS and OS times were observed in patients who received BTP than in those who received no BTP (median OS, 20.9 months versus 10.2 months; median PFS, 10.3 months versus 6.5 months). BTP was associated with a longer residual OS time at all specified landmarks and longer residual PFS time at week 18 than with no BTP.

In conclusion, this retrospective analysis provides supportive evidence that continued vascular endothelial growth factor suppression in advanced nonsquamous NSCLC patients is associated with favorable clinical outcomes.
Chemical activation of bagasse ash in cement mortar
Authors: Amin N. , Ali K. , Shah M. T. , Alam S.
Published: March 2011

The production of a large quantity of bagasse ash from sugar mills has become an environmental problem, but its use in cement mortar has provided a satisfactory solution to problems associated with waste management. In the present study, the effect of bagasse ash as a pozzolanic material on the partial replacement of cement and its activation by a chemical method using CaCl2.H2O was studied. The use of calcium chloride increased the strength of the cement very significantly. Equilibrium water extraction indicated that the addition of CaCl2.H2O decreased the evaporable moisture and the pH of the extract from hardened cement paste, which is an indication of enhanced pozzolanic reaction between the lime and bagasse ash. The optimum bagasse ash replacement for cement was found to be 10% without activator and 20% with 4% CaCl2.H2O. The results from both the strength and water extraction suggest that CaCl2.H2O is a good chemical activator.
Mineral additives geometry influence in cement pastes flow
Authors: Rubio-Hernández F. J. , Cerezo-Aizpún I. , Velázquez-Navarro J. F.
Published: March 2011

The flow behaviour of a fresh cement paste is dependent on its solid composition, but it cannot be predicted solely from the physico-chemical properties of the solid phase. The variation in rheological parameters (viscosity or consistency, index flow, and yield stress) was investigated on the basis of the geometric aspects of the solid additives (fly ash and silica fume) that were used in place of cement particles in the final composition of the pastes. The spherical particles (fly ash) showed a lower viscosity (consistency) and a weaker network (lower yield stress) when the water/binder ratio decreased. On the other hand, a higher polydispersity of the solid particles (silica fume) yielded an increase in the viscosity (consistency) and the yield stress. In both cases, the flow index was not affected by cement particle substitution.
Assessment of changes in physical characteristics due to leaching of hydration products from concrete
Authors: El-Dakroury A. , Ibrahim I. S. , Iyob I. E.
Published: March 2011

It is well known that changes in concrete properties such as the increase in porosity of the surface layer and reduction in strength occur because of material transfer due to dissolution and diffusion of hydration products when concrete comes into contact with water. The present study was an experimental investigation of test methods that can detect damage in cement composites, by immersion in highly acidic medium and measuring hot water permeability, capillary, water absorption and compressive strength. The applicability of immersion tests of cement paste were investigated and a model of change for physical properties such as porosity and strength due to leaching were constructed. The results indicated that the porosity could be calculated from the solid-phase calcium concentration, and the changes in the compressive strength, flexural strength, permeability coefficient and diffusion coefficient could be predicted for the degradation phenomenon caused by leaching. It was concluded that the porosity of paste after degradation caused by leaching can be predicted by the Powers' model, the model in which the increase in porosity through leaching is added.
Effect of additives on properties of magnesium phosphosilicate cement
Authors: Xing F. , Ding Z. , Li Z.-J.
Published: March 2011

Magnesium phosphate-based cements are rapid setting materials. Retarders are often used to prolong the setting time of magnesium phosphate-based cements. Magnesium phosphosilicate cement (MPSC) is a new type of magnesium phosphate-based cement, which is composed of magnesia, phosphate and silicate materials, such as fly ash. MPSC has the characteristics of rapid setting and high early strength. In the present study, the effect of different additives, sodium tripolyphosphate (ST), borax (NB) and boric acid (BA) on the properties of MPSC was investigated, including the setting time, temperature rise of cement during initial hydration and strength development. In comparison with the MPSC sample without additive, ST had an acceleration effect on the setting process, whereas NB and BA had a retarding effect on the hydration. BA had a longer retardation time than NB. The higher the rate of temperature rise, the higher was the reaction rate, the shorter was the setting time, and the higher was the early strength. Hydration products of MPSC were analysed by X-ray diffraction. The results showed that a cementitious hydrate, MgKPO4·6H2O (MKP), formed in the hardened cement paste. There was no new product formed after the additives were incorporated in the hydration system, they might influence the formation rate of MKP during reaction.
Use of bagasse ash in cement and its impact on the mechanical behaviour and chloride resistivity of mortar
Authors: Amin N.
Published: March 2011

In this investigation bagasse ash from the sugar industries of Khyber Pakhtoon Khwa was utilised in high-strength Portland cement mortar. The effects of bagasse ash content on the physical and mechanical properties of hardened mortar were studied, which include compressive strength, consistency, setting time and chloride diffusion. The results indicated that bagasse ash was an effective mineral admixture and pozzolan. The optimum replacement ratio of bagasse ash was found to be 20% of the cement, which reduced the chloride diffusion effectively up to more than 50%, without any adverse effects on other properties of the hardened cement mortar.
The study ofα-quartz reactivity towards alkali–silica reaction by X-ray powder diffraction
Authors: Cella F. , Marinoni N. , Cerulli T. , Salvioni D. , Pavese A.
Published: March 2011

The present study is a contribution to the understanding of α-quartz reactivity towards the alkali–silica reaction (ASR), based on the use of X-ray powder diffraction (XRPD) line broadening. In particular the relationship between α-quartz structural disorder and its potential alkali reactivity towards ASR was investigated by combining traditional and advanced analytical techniques. Two aggregates were characterised by means of optical, physical and chemical analyses. Their potential alkali-reactivity was then tested by the ultra-accelerated mortar-bar test (RILEM AAR-2). Moreover a full profile analysis by XRPD was performed to extract the microstructural features (crystallite size and microstrain) of α-quartz in two aggregates, revealing its degree of structural order. By comparing the mortar bar results with those from the XRPD analysis, a correlation between α-quartz microstructural features and its reactivity towards ASR is highlighted, even if the microstructural features of α-quartz were not the only parameter to be considered.
Study of potassium-based magnesium phosphate cement
Authors: Xing F. , Ding Z. , Li Z.-J.
Published: March 2011

A novel magnesium phosphate cement made from magnesia and potassium phosphate was studied. The objective of the study was to examine the basic characteristics and cementing mechanism of the cement. The effect of magnesia content on setting time, temperature rise during initial reaction and strength development of the cement mortar were examined. The reaction products of cement with water, and cementing structure were also examined. The results show that the cement was rapid setting and had high early strength. With the increase of magnesia content, the setting time of cement became shorter and the temperature rose higher during initial reaction. Compressive strength was also increased with increasing magnesia content. The microstructure of the hardened cement was studied by X-ray diffraction and scanning electron microscopy–energy dispersive spectroscopy. The reaction product in the cement is magnesium potassium phosphate hexhydrate (MgKPO4·6H2O-MKP).
FDiversity: an Integrated Tool to Estimate and Analyze Functional Diversity
Authors: Casanoves Fernando , Pla Laura E. , Di Rienzo Julio A.
Published: March 2011

Consensus exists about the role of functional diversity, but studies with empirical data sets are scarce. The handling of large data sets has been limited because of the lack of tools to analyze functional diversity and their components in an easy and friendly way. We have developed user‐friendly menu‐driven software to estimate and analyze functional diversity indices to facilitate good statistical practice by ecologists. Estimation of taxonomic biodiversity and functional diversity indices within the same analytic environment allows study of the relationship among estimated indices as well as their dependencies with other biotic and/or abiotic factors.
Serum Placental Growth Factor, Vascular Endothelial Growth Factor, Soluble Vascular Endothelial Growth Factor Receptor‐1 and ‐2 Levels in Periodontal Disease, and Adverse Pregnancy Outcomes
Authors: Sert Tuba , Kırzıoğlu F. Yeşim , Fentoğlu Özlem , Aylak Firdevs , Mungan Tamer
Published: March 2011

Background: The aim of this study is the evaluation of levels of serum interleukin (IL)‐1β, IL‐6, IL‐10, tumor necrosis factor (TNF)‐α, vascular endothelial growth factor (VEGF), placental growth factor (PIGF), and soluble VEGF receptor (sVEGFR)‐1 and ‐2 in the association between periodontal disease and adverse pregnancy outcomes.

Methods: One hundred and nine mothers, who recently gave birth, and 51 women who were not recently pregnant, aged 18 to 35 years, were included in this study. The mothers were classified as term birth, preterm birth (PTB), and preterm low birth weight (PLBW) in respect to their gestational age and baby's birth weight. The birth mothers were grouped as having gingivitis or periodontitis. The non‐pregnant group also included periodontally healthy patients. Venous blood samples were collected to evaluate serum IL‐1β, IL‐6, IL‐10, TNF‐α, VEGF, PIGF, and sVEGFR‐1 and ‐2 levels.

Results: Mother's weight, education, and income level were significantly associated with pregnancy outcomes. Serum levels of IL‐1β, TNF‐α, IL‐6, VEGF, and sVEGFR‐1 and ‐2 showed an increase in significance when related to pregnancy. Whereas in the PLBW group IL‐1β, VEGF, and sVEGFR‐2 levels were increased, in the PTB group sVEGFR‐1 levels were increased. Additionally, the patients in the PLBW group with periodontitis had higher serum levels of IL‐1β, VEGF, sVEGFR‐2, and IL‐1β/IL‐10.

Conclusion: The serum levels of IL‐1β, VEGF, and sVEGFR‐1 and ‐2 may have a potential effect on the mechanism of the association between periodontal disease and adverse pregnancy outcomes.
A Review of Screen Selection for Standalone Applications and a New Methodology
Authors: Chanpura Rajesh A. , Hodge Richard M. , Andrews Jamie S. , Toffanin Ezio P. , Moen Terje , Parlar Mehmet
Published: March 2011

Standalone screens (SASs) in open hole can provide highly reliable sand-control completions at a lower cost and with less operational complexity than other openhole sand-control completions and can provide long-term productivity performance comparable to other openhole completions when applied in the "right environment with the right procedures." Although many in the industry would agree with the preceding statement, there is no consensus on what the right environment is and what the right procedures are. Even when there is agreement on the applicability of SASs for a particular sand-size distribution, there are considerable differences in the recommended screen type and screen opening between various laboratories.

In this paper, we critically review the various laboratory testing procedures used in the industry and the interpretations made to evaluate screen performance and screen selection for SAS applications. We demonstrate that the way some of the laboratory tests are performed makes them biased toward one type of screen (wire wrap) and that some are interpreted without sufficient information such that they almost always favor another type of screen (premium mesh). We show that severe screen plugging with clean formation sand is almost never an issue and that the probability of screen plugging because of other factors can be minimized when proper precautions are taken. We propose that candidates for SAS applications be initially selected on the basis of sand-retention performance, with the final selection confirmed on the basis of screen/sand pack permeability measurements. In addition, on the basis of approximately 185 laboratory tests performed on various types of wire-wrap (6 to 16 gauge) and premium mesh (60 to 600 μm) screens for unconsolidated sands and using a set criterion for sand retention, we conclude that many of the currently used criteria in the industry for selection between gravel packing and SAS are highly conservative and unduly limit the possible application of SASs.
Keeping Immunisation Coverage Targets in Perspective
Authors: Brown David W.
Published: March 2011

Immunisation coverage targets have had a central role in global immunisation efforts. There is a growing focus
on achievement of immunisation coverage targets by national immunisation programmes, particularly where targets are
included as part of performance based funding arrangements. However, immunisation coverage targets should not become
a distraction to national immunisation programme managers whereby short run forces to lead to a shift or abandonment of
technically appropriate and sustainable activities in a country.
Evaluating Performance of Electricity Distribution Centers and Improving Relative Operational Efficiencies through Reorganization: A Case of Nepal
Authors: Jha Deependra K. , Yorino Naoto , Karki Nava Raj
Published: March 2011

This paper analyzes the performance of the electricity distribution system in Nepal. Weight restriction data envelopment analysis (DEA) technique has been used to quantify the relative operational efficiencies of the distribution centers (DCs) owned by Nepal Electricity Authority (NEA). The proposed model incorporates a wide range of variables that capture the essence of electricity distribution process. Decision makers opinion on the relevance and relative importance of the decision variables have been incorporated judiciously in the analysis in order to identify the possible improvement strategies for the DCs. This study also investigates the possibility of reorganization of the existing DCs inside the NEAs distribution framework on the basis of geographical convenience. Sensitivity analysis is carried out in order to check the robustness of the results and to suggest the direction for improvements. Strengths and weaknesses of individual DCs are identified based on the results of the sensitivity analysis.
Study of Whey Protein Concentrate Fortification in Cookies Variety Biscuits
Authors: Parate Vishal R. , Kawadkar Dilip K , Sonawane Shriram S.
Published: March 2011

Whey protein concentrate is one of the most cheaply available rich sources of quality proteins offering many health benefits, and it has the ability to improve the food products due to its various functional properties. In improving the nutritional status of biscuits, the incorporation of whey protein concentrate has proved its ideality. The objective of present study was to explore the possibility of fortifying the whey protein concentrate in the formulation of biscuits. Biscuits were prepared from the blend (wheat flour and whey protein concentrate) containing various wt% levels of whey protein concentrate (0, 20, 25, 30, 35 and 40 percent) using traditional creaming method. Prepared biscuits were then evaluated for chemical, physical and sensory properties. It was observed that the thickness of whey protein concentrate fortified biscuits increased with increasing wt% level of whey protein concentrate, whereas diameter, spread ratio, spread factor and weight decreased with increasing wt% level of incorporation. The sensory evaluation supported incorporation of maximum 25 percent level of whey protein concentrate.
Optimization of Drying Kinetics and Quality Parameters of Broccoli Florets
Authors: Mahn Andrea V , Antoine Paola , Reyes Alejandro
Published: March 2011

Drying kinetics of broccoli florets in a tunnel dryer was studied. Effective moisture diffusivity (Deff) and activation energy for moisture diffusion (E0) were estimated. The effect of air temperature, air flow rate and particle size on antioxidant capacity, greenness and texture were calculated through a 23 factorial design. Air flow rate and temperature significantly affected drying time. Deff fluctuated between 2.82 x 10-10 and 2.00 x 10-9 (m2/s), and E0 was around 42 KJ/mol, agreeing with values reported in literature. The maximum antioxidant activity was obtained at 60°C, air flow rate of 4 m/s and 1.5 cm particle diameter, resulting in a 70 percent reduction in free radical scavenging ability and a 29 percent increase in total reductive capability. Air temperature had significant effect on greenness, and air flow rate significantly affected texture. The optimization of convective drying of broccoli allows maximizing antioxidant activity and minimizing cost by saving energy and time.
Feather Keratin Hydrolysis by an Aquatic Bacterium Meiothermus I40 from Hot Spring Water
Authors: Yang Jing-Iong , Kuo Jen-Min , Chen Wen-Ming , Ke Huei-Jing , Chou Yi-Ju
Published: March 2011

After undergoing keratinase digestion, feather wastes could have a great potential as a source of proteins and amino acids for many applications. In this study, the fermentation conditions of feather-degrading Meiothermus sp. strain I40 (I40) were optimized to enhance the biodegradation of chicken feather to hydrolysates. Initially, the factors essential for I40 keratinase production in submerged fermentation were screened, whereas response surface methodology (RSM) was then employed to evaluate the interactions among the effective factors. At first stage, eight fermentation parameters were screened using a Plackett-Burman (PB) design. Four effective factors identified by PB screening, namely feather concentration, tryptone concentration, yeast extract concentration, and incubation temperature, were further investigated their effects on keratinase production by RSM using central composite design (CCD). The I40 fermentation conditions for maximal keratinase activity were as follows: tryptone concentration 0.16 percent (w/v), yeast extract concentration 0.27 percent (w/v), feather concentration 0.08 percent (w/v), and incubation temperature at 51.7°C for 72 hr under 120 rev/min shaking. Compared to the initial stage, a 13.3-fold increase in keratinase activity was achieved when I40 incubated in the optimized conditions.
A New Model for Predicting Sorption Isotherm of Water in Foods
Authors: Cortés Farid B. , Chejne Farid , Rojano Benjamin
Published: March 2011

A new model for predicting sorption isotherms of type II and III based on the Polanyi theory is proposed. This model allows the prediction of the sorption isotherms at different temperatures from one experimental isotherm. The theoretical predictions of isotherms and isosteric heat were validated successfully using data from literature for twenty one foods. This method allows total experimental time and operation costs to be reduced.