bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin Regulates Glucagon-Like Peptide-1 Secretion from the Enteroendocrine L Cell
Authors: Lim Gareth E. , Huang Guan J. , Flora Nina , LeRoith Derek , Rhodes Christopher J. , Brubaker Patricia L.
Published: September 2008

Insulin resistance and type 2 diabetes mellitus are associated with impaired postprandial secretion of glucagon-like peptide-1 (GLP-1), a potent insulinotropic hormone. The direct effects of insulin and insulin resistance on the L cell are unknown. We therefore hypothesized that the L cell is responsive to insulin and that insulin resistance impairs GLP-1 secretion. The effects of insulin and insulin resistance were examined in well-characterized L cell models: murine GLUTag, human NCI-H716, and fetal rat intestinal cells. MKR mice, a model of chronic hyperinsulinemia, were used to assess the function of the L cell in vivo. In all cells, insulin activated the phosphatidylinositol 3 kinase-Akt and MAPK kinase (MEK)-ERK1/2 pathways and stimulated GLP-1 secretion by up to 275 ± 58%. Insulin resistance was induced by 24 h pretreatment with 10−7m insulin, causing a marked reduction in activation of Akt and ERK1/2. Furthermore, both insulin-induced GLP-1 release and secretion in response to glucose-dependent insulinotropic peptide and phorbol-12-myristate-13-acetate were significantly attenuated. Whereas inhibition of phosphatidylinositol 3 kinase with LY294002 potentiated insulin-induced GLP-1 release, secretion was abrogated by inhibiting the MEK-ERK1/2 pathway with PD98059 or by overexpression of a kinase-dead MEK1-ERK2 fusion protein. Compared with controls, MKR mice were insulin resistant and displayed significantly higher fasting plasma insulin levels. Furthermore, they had significantly higher basal GLP-1 levels but displayed impaired GLP-1 secretion after an oral glucose challenge. These findings indicate that the intestinal L cell is responsive to insulin and that insulin resistance in vitro and in vivo is associated with impaired GLP-1 secretion.

Insulin is a novel secretagogue of the incretin hormone, glucagon-like peptide-1 (GLP-1), and L cell insulin resistance impairs heterologous secretagogue-induced GLP-1 secretion in vitro and in vivo.
Evidence of Diminished Glucose Stimulation and Endoplasmic Reticulum Function in Nonoscillatory Pancreatic Islets
Authors: Jahanshahi Pooya , Wu Runpei , Carter Jeffrey D. , Nunemaker Craig S.
Published: September 2008

Pulsatility is a fundamental feature of pancreatic islets and a hallmark of hormone secretion. Isolated pancreatic islets endogenously generate rhythms in secretion, metabolic activity, and intracellular calcium ([Ca2+]i) that are important to normal physiological function. Few studies have directly compared oscillatory and nonoscillatory islets to identify possible differences in function. We investigated the hypothesis that the loss of these oscillations is a leading indicator of islet dysfunction by comparing oscillatory and nonoscillatory mouse islets for multiple parameters of function. Nonoscillatory islets displayed elevated basal [Ca2+]i and diminished [Ca2+]i response and insulin secretory response to 3–28 mm glucose stimulation compared with oscillatory islets, suggesting diminished glucose sensitivity. We investigated several possible mechanisms to explain these differences. No differences were observed in mitochondrial membrane potential, estimated ATP-sensitive potassium channel and L-type calcium channel activity, or cell death rates. Nonoscillatory islets, however, showed a reduced response to the sarco(endo)plasmic reticulum calcium ATPase inhibitor thapsigargin, suggesting a disruption in calcium homeostasis in the endoplasmic reticulum (ER) compared with oscillatory islets. The diminished ER calcium homeostasis among nonoscillatory islets was also consistent with the higher cytosolic calcium levels observed in 3 mm glucose. Inducing mild damage with low-dose proinflammatory cytokines reduced islet oscillatory capacity and produced similar effects on glucose-stimulated [Ca2+]i, basal [Ca2+]i, and thapsigargin response observed among untreated nonoscillatory islets. Our data suggest the loss of oscillatory capacity may be an early indicator of diminished islet glucose sensitivity and ER dysfunction, suggesting targets to improve islet assessment.

The loss of islet calcium oscillations correlates with impaired calcium regulation and reduced insulin secretion, suggesting oscillatory capacity is important to islet health and function.
Mouse Models of Alzheimer’s Dementia: Current Concepts and New Trends
Authors: Torres-Aleman I.
Published: September 2008

It is lay knowledge now that Alzheimer’s dementia (AD) is one of the most devastating diseases afflicting our societies. A major thrust in search for a cure has relied in the development of animal models of the disease. Thanks to progress in the genetics of the rare inherited forms of AD, various transgenic mouse models harboring human mutated proteins were developed, yielding very significant advancements in the understanding of pathological pathways. Although these models led to testing many different new therapies, none of the preclinical successes have translated yet into much needed therapeutic improvements. Further insight into the metabolic disturbances that are probably associated with the onset of the disease may also rely on new animal models of AD involving insulin/IGF-I signaling that could mimic the far most common sporadic forms of AD associated with old age. Combination of models of familial AD that develop severe amyloidosis with those displaying defects in insulin/IGF-I signaling may help clarify the link between putative initial metabolic disturbances and mechanisms of pathological progression.
Role of Adenosine 5′-Monophosphate-Activated Protein Kinase in Interleukin-6 Release from Isolated Mouse Skeletal Muscle
Authors: Glund Stephan , Treebak Jonas T. , Long Yun Chau , Barres Romain , Viollet Benoit , Wojtaszewski Jorgen F. , Zierath Juleen R.
Published: September 2008

IL-6 is released from skeletal muscle during exercise and has consequently been implicated to mediate beneficial effects on whole-body metabolism. Using 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR), a pharmacological activator of 5′-AMP-activated protein kinase (AMPK), we tested the hypothesis that AMPK modulates IL-6 release from isolated muscle. Skeletal muscle from AMPKα2 kinase-dead transgenic, AMPKα1 knockout (KO) and AMPKγ3 KO mice and respective wild-type littermates was incubated in vitro, in the absence or presence of 2 mmol/liter AICAR. Skeletal muscle from wild-type mice was also incubated with the AMPK activator A-769662. Incubation of mouse glycolytic extensor digitorum longus and oxidative soleus muscle for 2 h was associated with profound IL-6 mRNA production and protein release, which was suppressed by AICAR (P < 0.001). Basal IL-6 release from soleus was increased between AMPKα2 kinase-dead and AMPKα1 KO and their respective wild-type littermates (P < 0.05), suggesting AMPK participates in the regulation of IL-6 release from oxidative muscle. The effect of AICAR on muscle IL-6 release was similar between AMPKα2 KD, AMPKα1 KO, and AMPKγ3 KO mice and their respective wild-type littermates (P < 0.001), indicating AICAR-mediated suppression of IL-6 mRNA expression and protein release is independent of AMPK function. However, IL-6 release from soleus, but not extensor digitorum longus, was reduced 45% by A-769662. Our results on basal and A-769662-mediated IL-6 release provide evidence for a role of AMPK in the regulation of IL-6 release from oxidative skeletal muscle. Furthermore, in addition to activating AMPK, AICAR suppresses IL-6 release by an unknown, AMPK-independent mechanism.

Using transgenic and knockout mouse models to perturb AMP-activated protein kinase (AMPK) signaling, we provide evidence that AMPK-dependent pathways regulate IL-6 release from isolated oxidative skeletal muscle.
Research Resource: Gene Expression Profile for Ectopic Versus Eutopic Endometrium Provides New Insights into Endometriosis Oncogenic Potential
Authors: Borghese Bruno , Mondon Françoise , Noël Jean-Christophe , Fayt Isabelle , Mignot Thérèse-Marie , Vaiman Daniel , Chapron Charles
Published: September 2008

Endometriosis is a common gynecological disorder characterized by pain and infertility, where the lesions disseminate everywhere in the body with a preference for the pelvis. In that, it could be regarded as a benign metastatic disease, because its issue is not fatal. However, the molecular bases of this intriguing clinical condition are not well known. The objective of this study is to characterize the transcriptome differences between eutopic vs. ectopic endometrium with a special interest in pathways involved in cancerogenesis. We performed two hybridizations in technical replicate on highly specific long oligonucleotides microarrays (NimbleGen), with cDNA prepared from six-patients pools, where the same patient provided both eutopic and ectopic endometrium (endometriomas). To confirm the expression microarrays data, quantitative RT-PCR validation was performed on 12 individuals for 20 genes. Over 8000 transcripts were significantly modified (more than twice) in the lesions corresponding to 5600 down- or up-regulated genes. These were clustered through DAVID Bioinformatics Resources into 55 functional groups. The data are presented in a detailed and visual way on 24 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways implemented with induction ratios for each differentially expressed gene. An outstanding control of the cell cycle and a very specific modulation of the HOX genes were observed and provide some new evidence on why endometriosis only very rarely degenerates into cancer. The study constitutes a noteworthy update of gene profiling in endometriosis, by delivering the most complete and reliable list of dysregulated genes to date.
The Generalised Coupon Collector Problem
Authors: Neal Peter
Published: September 2008

Coupons are collected one at a time from a population containingndistinct types of coupon. The process is repeated until allncoupons have been collected and the total number of draws,Y, from the population is recorded. It is assumed that the draws from the population are independent and identically distributed (draws with replacement) according to a probability distributionXwith the probability that a type-icoupon is drawn being P(X=i). The special case where each type of coupon is equally likely to be drawn from the population is the classic coupon collector problem. We consider the asymptotic distributionY(appropriately normalized) as the number of couponsn→ ∞ under general assumptions upon the asymptotic distribution ofX. The results are proved by studying the total number of coupons,W(t), not collected intdraws from the population and noting that P(Y≤t) = P(W(t) = 0). Two normalizations ofYare considered, the choice of normalization depending upon whether or not a suitable Poisson limit exists forW(t). Finally, extensions to theK-coupon collector problem and the birthday problem are given.
Hitting Time and Inverse Problems for Markov Chains
Authors: de la Peña Victor , Gzyl Henryk , McDonald Patrick
Published: September 2008

Let Wn be a simple Markov chain on the integers. Suppose that Xn is a simple Markov chain on the integers whose transition probabilities coincide with those of Wn off a finite set. We prove that there is an M > 0 such that the Markov chain Wn and the joint distributions of the first hitting time and first hitting place of Xn started at the origin for the sets {-M, M} and {-(M + 1), (M + 1)} algorithmically determine the transition probabilities of Xn.
The Noisy Veto-Voter Model: A Recursive Distributional Equation on [0, 1]
Authors: Jacka Saul , Sheehan Marcus
Published: September 2008

We study a particular example of a recursive distributional equation (RDE) on the unit interval. We identify all invariant distributions, the corresponding ‘basins of attraction’, and address the issue of endogeny for the associated tree-indexed problem, making use of an extension of a recent result of Warren.
On Prolific Individuals in a Supercritical Continuous-State Branching Process
Authors: Bertoin Jean , Fontbona Joaquin , Martínez Servet
Published: September 2008

We describe the genealogy of individuals with infinite descent in a supercritical continuous-state branching process.
Epidemics on Random Graphs with Tunable Clustering
Authors: Britton Tom , Deijfen Maria , Lagerås Andreas N. , Lindholm Mathias
Published: September 2008

In this paper a branching process approximation for the spread of a Reed-Frost epidemic on a network with tunable clustering is derived. The approximation gives rise to expressions for the epidemic threshold and the probability of a large outbreak in the epidemic. We investigate how these quantities vary with the clustering in the graph and find that, as the clustering increases, the epidemic threshold decreases. The network is modeled by a random intersection graph, in which individuals are independently members of a number of groups and two individuals are linked to each other if and only if there is at least one group that they are both members of.
Epidemic Size in the SIS Model of Endemic Infections
Authors: Kessler David A.
Published: September 2008

We study the susceptible-infected-susceptible model of the spread of an endemic infection. We calculate an exact expression for the mean number of transmissions for all values of the population size (N) and the infectivity. We derive the large-N asymptotic behavior for the infectivitiy below, above, and in the critical region. We obtain an analytical expression for the probability distribution of the number of transmissions, n, in the critical region. We show that this distribution has an n-3/2 singularity for small n and decays exponentially for large n. The exponent decreases with the distance from the threshold, diverging to ∞ far below and approaching 0 far above.
First Passage Times for Markov Additive Processes with Positive Jumps of Phase Type
Authors: Breuer Lothar
Published: September 2008

The present paper generalises some results for spectrally negative Lévy processes to the setting of Markov additive processes (MAPs). A prominent role is assumed by the first passage times, which will be determined in terms of their Laplace transforms. These have the form of a phase-type distribution, with a rate matrix that can be regarded as an inverse function of the cumulant matrix. A numerically stable iteration to compute this matrix is given. The theory is first developed for MAPs without positive jumps and then extended to include positive jumps having phase-type distributions. Numerical and analytical examples show agreement with existing results in special cases.
Functional Large Deviations and Moderate Deviations for Markov-Modulated Risk Models with Reinsurance
Authors: Gao Fuqing , Yan Jun
Published: September 2008

We establish a functional large deviation principle and a functional moderate deviation principle for Markov-modulated risk models with reinsurance by constructing an exponential martingale approach. Lundberg's estimate of the ruin time is also presented.
Induction into the Hall of Fame: tracing the lineage of Spemann's organizer
Authors: Harland Richard
Published: September 2008

The grafting experiments of Spemann and Mangold have been a textbook classic for years, but as with many conclusions from experimental embryology,the idea that the dorsal lip of the blastopore `organized' the early patterning of the embryo has sometimes come under question. In their 1983 paper in JEEM, Smith and Slack extended these classical experiments in newts to the now-standard amphibian model Xenopus laevis. By using injected lineage tracers, they distinguished the fates of graft and host, and showed unambiguously that the organizer is responsible for neural induction and that it dorsalizes the mesoderm.
Laparoscopic cholecystectomy in a small rural hospital in Kashmir Valley, India
Authors: Mir Iqbal Saleem , Mohsin Mir , Majid Tafazul , Wani Khurshid , Mehmood-ul-Hasan  , Kirmani Omar , Naqshbandi Javed , Maqbool Mohammed
Published: September 2008

This study evaluates the feasibility of performing laparoscopic cholecystectomy in order to reduce the expenditure in a 28-bed sub-district hospital in Kashmir, India. We report on a prospective clinical trail involving patients with gall bladder disease reported to the hospital from June 2005 till May 2007.
Concomitant TB and cryptococcosis in HIV-infected patients
Authors: Rawat D , Capoor M R , Nair D , Deb M , Aggarwal P
Published: September 2008

Four cases of concomitant tuberculosis and cryptococcosis infection in HIV-positive patients are described. As the HIV pandemic progresses and the proportion of patients with end-stage disease increases, a high suspicion of incidence and unusual forms of infections must always be kept in mind.
Pigs are the most important animal reservoir for Tunga penetrans (jigger flea) in rural Nigeria
Authors: Ugbomoiko Uade S , Ariza Liana , Heukelbach Jorg
Published: September 2008

We examined the domestic animals and rodents in a community in rural Nigeria. Of the 133 animals examined, 29 (21.8%) were infested, the highest prevalence of infestation and highest parasite load was found in the pigs (prevalence 54.8%, median = nine embedded parasites), followed by dogs (45.5%; median = 4), Rattus rattus (29.4%; median = 2) and Mus minutoides (15.4%; median = 1.5). Of all the tungiasis lesions identified 83% were found in pigs. Our data confirm that tungiasis is a zoonotic disease, and that pigs are its most important animal reservoir in this endemic community.
Addressing the attitudes of service providers: increasing access to professional midwifery care in Nepal
Authors: Clapham S , Pokharel D , Bird C , Basnett I
Published: September 2008

Increasing access to professional care during labour and delivery is the central strategy in Nepal's commitment to reducing its maternal mortality ratio. This paper outlines a number of complementary interventions used by the Nepal Safer Motherhood Project to address the negative attitudes prevalent among service providers, which is a contributing factor to the under-utilization of the health-care services. The perspectives of the community and the service providers are presented, with a discussion of the importance of effective communication, the establishment of positive relationships and a demonstration of the critical role of local ownership and involvement in bringing about a positive change.
The incidence of urinary tract infections in febrile children during a two-year period in Tehran, Iran
Authors: Panahi Yunes , Beiraghdar Fatemeh , Moharamzad Yashar , Matinzadeh Zahra Khalili , Einollahi Behzad
Published: September 2008

Of 433 febrile children examined in the paediatric clinics of two university hospitals in Tehran, Iran, 39 (9%) children (27 girls and 12 boys) were diagnosed as having urinary tract infection in which Escherichia coli was the most frequently detected pathogen (84.6%). According to the voiding cystourethrogram, nine (75%) boys and 17 (63%) girls had urinary tract abnormalities. This result is slightly higher than seen in other reports from developing countries.
Risk perception and water purification practices for water-borne parasitic infections in remote Nepal
Authors: Kovalsky Adrienne N , Lacey Steven E , Kaphle Upendra Raj , Vaughn James M
Published: September 2008

This study assesses water-borne infection risk perception and water boiling habits in a remote Sankhuwasava region of Nepal using a brief interview-style questionnaire. All subjects were aware of the risks associated with drinking unpurified water, but a majority (65%) reported they did not boil water regularly, and almost 60% of villagers interviewed had history of infection despite their boiling practices. In contrast to reports from other communities in Nepal, risk awareness was sufficient in this region. Water boiling alone did not confer protection. Future efforts should target sanitation, screening, and other sources of contamination.
Epidemiology of nosocomial infections in medicine intensive care unit at a tertiary care hospital in northern India
Authors: Habibi Shabina , Wig Naveet , Agarwal Sunil , Sharma Surendra K , Lodha Rakesh , Pandey Ravindra M , Kapil Arti
Published: September 2008

This prospective observational study describes the rates of nosocomial infections (NI), the sites of infection, the pathogens involved, their antibiogram and the risk factors at a tertiary care hospital in northern India. In 62 of the 182 enrolled patients 95 episodes of NI were recorded (incidence rate 28.6/1000 person days): pneumonia (77%); urinary tract infection (24%) and blood stream infection (24%). All isolates of Acinetobacter, Pseudomonas and Klebsiella and 83.3% of Escherichia coli were resistant to the third generation cephalosporins. An increased duration of the time spent in intensive care units and days of intervention were associated with incident NI.
Does breast feeding provide protection against acute appendicitis? A case-control study
Authors: Alves João Guilherme Bezerra , Figueiroa José Natal , Barros Isabela
Published: September 2008

Breast feeding stimulates a more tolerant lymphoid tissue at the base of the appendix and this could provide protection against acute appendicitis. Two studies reported that children and adolescents with appendicitis were less likely to have been breast fed. In a case-control study of 200 children with histologically confirmed acute appendicitis matched by 200 siblings with the same sex and difference age – up to three-year-old – we found breast feeding in at least the first two months of life and for more than four months provides protection against acute appendicitis. These findings suggesting that breast feeding may possibly give protection against the development of appendicitis.
Maternal morbidity during postpartum period in a village of north India: a prospective study
Authors: Patra Somdatta , Singh Bir , Reddaiah V P
Published: September 2008

This prospective community-based study was conducted in the village of Chhainsa, Haryana, India, in order to discover the incidence and types of postpartum morbidity and the factors associated with the morbidities. The subjects were followed up to 42 days of postpartum with a minimum of three visits; the first visit was within 14 days of delivery and subsequent visits were every 14 days. A first visit was made to 211 women and 174 (82.46%) completed the study. Seventy-four percent reported at least one morbidity and there were 1.75 reported morbidities per woman per postpartum period. Common problems reported were: weakness, lower abdominal pain, perineal pain, abnormal vaginal discharge, high fever, breast problems, excessive vaginal bleeding, etc. There was greater morbidity among women of lower socioeconomic status, parity >4, birth interval >36 months, having a breech or caesarean delivery or a delivery assisted by relatives/neighbours. A significant positive association was found between age and non-maintenance of the ‘five cleans’ during delivery. Seventy-five percent of those who had reported morbidity had taken some action, but only 20% sought help from a qualified doctor and 14% from other health workers.
A study of clinico-haematological profiles of pancytopenia in children
Authors: Gupta V , Tripathi S , Tilak V , Bhatia B D
Published: September 2008

We report on the clinico-haematological profile of pancytopenia in children from the Departments of Pediatrics and Pathology, Institute of Medical Sciences, Banaras Hindu University, India, over a period of 30 months. Pancytopenia was defined as: haemoglobin <10 g/dL, absolute neutrophil count 1.5 × 109/L and platelet count <100 × 109/L. A detailed history, clinical examination and haematological parameters were recorded. Bone marrow aspiration and trephine biopsy were carried out in all cases. One hundred and five cases aged 1.5–18 years, with a mean age of 8.6 years, were included in the study. Aplastic anaemia was the most common cause of pancytopenia (43%) followed by acute leukaemia (25%). Infections were the third most common cause of pancytopenia of which kala azar was the most common. Megaloblastic anaemia was seen in 6.7%.
Novel noncoding antisense RNA transcribed from human anti-NOS2A locus is differentially regulated during neuronal differentiation of embryonic stem cells
Authors: Korneev Sergei A. , Korneeva Elena I. , Lagarkova Marya A. , Kiselev Sergei L. , Critchley Giles , O'Shea Michael
Published: September 2008

Here, we report on the discovery of a locus in the human genome, which evolved by gene duplication followed by an internal DNA inversion. This locus exhibits high sequence similarity to the gene for the inducible isoform of NOS protein (NOS2A) and is transcribed into a noncoding RNA containing a region of significant antisense homology with the NOS2A mRNA. We show that this antisense transcript (anti-NOS2A RNA) is expressed in different types of brain tumors, including meningiomas and glioblastomas. More importantly, we demonstrate that the expression profiles of the anti-NOS2A RNA and the NOS2A mRNA exhibit concurrent reciprocal changes in undifferentiated human embryonic stem cells (hESCs) and in hESCs induced to differentiate into neurogenic precursors such as neurospheres. As NOS2A has a role in neurogenesis, our results suggest that the anti-NOS2A RNA is involved in the regulation of neuronal differentiation of hESCs through the modulation of NOS2A gene expression.
Ribosomes bind leaderless mRNA in Escherichia coli through recognition of their 5′-terminal AUG
Authors: Brock Jay E. , Pourshahian Soheil , Giliberti Jacqueline , Limbach Patrick A. , Janssen Gary R.
Published: September 2008

Leaderless mRNAs are translated in the absence of upstream signals that normally contribute to ribosome binding and translation efficiency. In order to identify ribosomal components that interact with leaderless mRNA, a fragment of leaderless cI mRNA from bacteriophage λ, with a 4-thiouridine (4S-U) substituted at the +2 position of the AUG start codon, was used to form cross-links to Escherichia coli ribosomes during binary (mRNA+ribosome) and ternary (mRNA+ribosome+initiator tRNA) complex formation. Ribosome binding assays (i.e., toeprints) demonstrated tRNA-dependent binding of leaderless mRNA to ribosomes; however, cross-links between the start codon and 30S subunit rRNA and r-proteins formed independent of initiator tRNA. Toeprints revealed that a leaderless mRNA's 5′-AUG is required for stable binding. Furthermore, the addition of a 5′-terminal AUG triplet to a random RNA fragment can make it both competent and competitive for ribosome binding, suggesting that a leaderless mRNA's start codon is a major feature for ribosome interaction. Cross-linking assays indicate that a subset of 30S subunit r-proteins, located at either end of the mRNA tunnel, contribute to tRNA-independent contacts and/or interactions with a leaderless mRNA's start codon. The interaction of leaderless mRNA with ribosomes may reveal features of mRNA binding and AUG recognition that are distinct from known signals but are important for translation initiation of all mRNAs.
Peptidyl-CCA deacylation on the ribosome promoted by induced fit and the O3′-hydroxyl group of A76 of the unacylated A-site tRNA
Authors: Simonović Miljan , Steitz Thomas A.
Published: September 2008

The last step in ribosome-catalyzed protein synthesis is the hydrolytic release of the newly formed polypeptide from the P-site bound tRNA. Hydrolysis of the ester link of the peptidyl-tRNA is stimulated normally by the binding of release factors (RFs). However, an unacylated tRNA or just CCA binding to the ribosomal A site can also stimulate deacylation under some nonphysiological conditions. Although the sequence of events is well described by biochemical studies, the structural basis of the mechanism underlying this process is not well understood. Two new structures of the large ribosomal subunit of Haloarcula marismortui complexed with a peptidyl-tRNA analog in the P site and two oligonucleotide mimics of unacylated tRNA, CCA and CA, in the A site show that the binding of either CA or CCA induces a very similar conformational change in the peptidyl-transferase center as induced by aminoacyl-CCA. However, only CCA positions a water molecule appropriately to attack the carbonyl carbon of the peptidyl-tRNA and stabilizes the proper orientation of the ester link for hydrolysis. We, thus, conclude that both the ability of the O3′-hydroxyl group of the A-site A76 to position the water and the A-site CCA induced conformational change of the PTC are critical for the catalysis of the deacylation of the peptidyl-tRNA by CCA, and perhaps, an analogous mechanism is used by RFs.
TOR regulates the subcellular distribution of DIM2, a KH domain protein required for cotranscriptional ribosome assembly and pre-40S ribosome export
Authors: Vanrobays Emmanuel , Leplus Alexis , Osheim Yvonne N. , Beyer Ann L. , Wacheul Ludivine , Lafontaine Denis L.J.
Published: September 2008

Eukaryotic ribosome synthesis is a highly dynamic process that involves the transient association of scores of trans-acting factors to nascent pre-ribosomes. Many ribosome synthesis factors are nucleocytoplasmic shuttling proteins that engage the assembly pathway at early nucleolar stages and escort pre-ribosomes to the nucleoplasm and/or the cytoplasm. Here, we report that two 40S ribosome synthesis factors, the KH-domain protein DIM2 and the HEAT-repeats/Armadillo-domain and export factor RRP12, are nucleolar restricted upon nutritional, osmotic, and oxidative stress. Nucleolar entrapment of DIM2 and RRP12 was triggered by rapamycin treatment and was under the strict control of the target of rapamycin (TOR) signaling cascade. DIM2 binds pre-rRNAs directly through its KH domain at the 5′-end of ITS1 (D-A2 segment) and, consistent with its requirements in early nucleolar pre-rRNA processing, is required for efficient cotranscriptional ribosome assembly. The substitution of a single and highly conserved amino acid (G207A) within the KH motif is sufficient to inhibit pre-rRNA processing in a fashion similar to genetic depletion of DIM2. DIM2 carries an evolutionarily conserved putative nuclear export sequence (NES) at its carboxyl-terminal end that is required for efficient pre-40S ribosome export. Strikingly, DIM2 and RRP12 are both involved in the nucleocytoplasmic translocation of pre-ribosomes, suggesting that this step in the ribosome assembly pathway has been selected as a regulatory target for the TOR pathway.
Mechanistic insights from reversible splicing catalysis: FIGURE 1.
Authors: Smith Duncan J. , Konarska Maria M.
Published: September 2008

Recent work demonstrating the ability of spliceosomes purified after the second catalytic step of splicing to efficiently reverse both steps of the reaction provides answers to several unresolved questions regarding the splicing reaction, and raises many more.
An Audit of Concomitant Dental Anomalies with Maxillary Talon Cusps in a Group of Children from Hong Kong
Authors: Cho Shiu-Yin , Ki Yung , Chu Vanessa , Lee Chun-Kei
Published: September 2008

Aim

To investigate the prevalence of various concomitant dental anomalies in Hong Kong children with true talon cusps on the permanent maxillary incisors.

Methods

Dental records and radiographs of a group of Hong Kong Chinese primary schoolchildren with true talon cusps (half crown height or more) on one or more permanent maxillary incisors were selected and studied retrospectively. The prevalence of various dental anomalies in this group of children was compared with that of the general population of Hong Kong Chinese children of similar age.

Results

A total of 11,537 records were reviewed and 58 children with true talon cusps on one or more permanent maxillary incisors were identified. A total of 69 permanent maxillary incisors were affected, of which all except one were lateral incisors. Dens evaginatus on premolars, supernumerary teeth in the anterior maxilla, and hypodontia were found in 5 (8.6%), 5 (8.6%), and 5 (8.6%) cases respectively. The prevalence of supernumerary teeth was significantly higher in children with true talon cusps as compared with the results of two previous general studies of Chinese children of similar age ( P<0.05, Fisher's exact test).

Conclusion

Children with true talon cusps on the permanent maxillary incisors were more frequently affected by supernumerary teeth in the anterior maxilla. Further studies with a larger sample are needed to confirm a true association.
I hope we won't have to understand racism one day: Researching or reproducing race in social psychological research?
Authors: Howarth Caroline
Published: September 2008

This paper examines the reification and problemization of ‘race’ in Psychological research in both influential studies in the field and in my empirical work. The main argument is that we need to examine how representations of ‘race’ are assumed, produced and contested in research practice. This argument is made by (a) showing how research in the area adopts everyday representations of ‘race’ as essentialized and (b) with an illustration of the construction of ‘race’ within my study. This study explores how children in a predominantly white setting accept and contest representations that race. twenty two children from a range of cultural backgrounds volunteered to discuss their views and experiences of ‘race’ and racism in a naturalistic research activity. The analysis reveals that racialized difference is something that is constructed as both ‘real’ — in that it can be seen, touched and even caught from ‘the other’ and simultaneously something that is constructed, imposed and damaging. This highlights the possibilities for racialized others to take up positions as agents and not (only) as objects of the racializing and racist gaze, and so presents the case for thinking, debating and researching beyond reifying representations of ‘race’. This has important lessons for social psychology: namely, we cannot continue to take racial categorization as a naturalistic or self‐evident aspect of the social worlds that our discipline plays an important role in constructing and defending.
How does Sam feel?: Children's labelling and drawing of basic emotions
Authors: Brechet Claire , Baldy René , Picard Delphine
Published: September 2008

This study compares the ability of children aged from 6 to 11 to freely produce emotional labels based on detailed scenarios (labelling task), and their ability to depict basic emotions in their human figure drawing (subsequent drawing task). This comparison assesses the relevance of the use of a human figure drawing task in order to test children's comprehension of basic emotions. Such a comparison has never been undertaken up to now, the two tasks being seen as belonging to relatively separate fields of investigation. Results indicate corresponding developmental patterns for both tasks and a clear‐cut gap between simple emotions (happiness and sadness) and complex emotions (anger, fear, and disgust) in the ability to label and to depict basic emotions. These results suggest that a drawing task can be used to assess children's understanding of basic emotions. Results are discussed according to the development of perceptual skills and the development of emotion conceptualization.
Associations between parental control and children's overt and relational aggression
Authors: Kuppens Sofie , Grietens Hans , Onghena Patrick , Michiels Daisy
Published: September 2008

The present study examined specialized associations between parental control and child aggression in a sample of 600 8‐ to 10‐years old children. Parental control dimensions and aggression subtypes were assessed using multiple informants (i.e. children, mothers, fathers, peers, and teachers). In line with expectations, parental physical punishment was positively associated with overt aggression, whereas parental psychological control was positively associated with relational aggression in both girls and boys. In addition, this study demonstrated that if both parents employed similar parenting strategies, it appeared to have a cumulative effect on child aggressive behaviour. Associations involving overt aggression were more pronounced for boys than girls, whereas associations involving relational aggression were not moderated by gender. Overall, the present study contributes to an emerging research field by supporting the hypothesis of specialized associations between parental control and child aggression.
Four-wave mixing and wavelength conversion in coupled-resonator optical waveguides
Authors: Melloni Andrea , Morichetti Francesco , Martinelli Mario
Published: September 2008

The four-wave mixing process in coupled-resonator optical waveguides is considered in detail and an approximate and simple approach allowing one to estimate the conversion efficiency is proposed. The analytical results are verified through a reliable and complete numerical technique taking into account nonlinear induced phase modulations, the large-signal regime, and the pulse shape evolution along the structure. The conversion efficiency is enhanced by the slow down factor to the fourth power and the impact of attenuation and phase mismatch are carefully investigated. The main aim of this study is to provide a technique to design efficient and compact wavelength converters. Two examples of devices operating on signals at 10 and 50 Gbits/s are presented and discussed. Pulse distortions induced by chromatic dispersion, frequency detuning, and slow down factor wavelength dependence are examined and the beneficial role of the nonlinear induced phase modulation on the phase mismatch is pointed out. Numerical examples show that with typical semiconductor characteristics, very high conversion efficiencies with pump powers of only a few tenths of milliwatts are achievable.
Fluorescence Quenching of Meso-Tetrakis(p-Sulfonatophenyl)Porphyrin (TSPP) by certain Organic Dyes
Authors: Kathiravan A. , Renganathan R.
Published: September 2008

The fluorescence quenching of meso-tetrakis (p-sulfonatophenyl) porphyrin (TSPP) by certain anthraquinone and azo dyes has been investigated using steady state fluorescence technique. The dyes used were Uniblue-A, Acid blue 129, Alizarin, Alizarin red S, Erichrome Black T, Tartrazine, Methyl orange, Methyl red, Acid orange 63 and Congo red. The quenching was found to obey Stern-Volmer equation and the corresponding Stern-Volmer plots were linear. The quenching rate constant (k

q
) is in the order of 0.19–6.08×1012 M−
1s−
1. This study reveals effective quenching of TSPP by organic dyes.
Nonlinear Dynamics in the Uncatalyzed Bromate–Pyrocatechol Reaction
Authors: Harati Mohammad , Wang Jichang
Published: September 2008

Spontaneous chemical oscillations are uncovered in the uncatalyzed bromate–pyrocatechol reaction conducted in a stirred batch reactor. Phase diagrams show that the oscillatory behavior is more sensitive to the ratio of [bromate]/[pyrocatechol] than their actual concentrations. The long induction time observed in the system is insensitive to the initial presence of brominated pyrocatechol species. Quenching experiments illustrate that the studied chemical oscillator is both bromide and radical controlled. In addition, this new uncatalyzed bromate oscillator exhibits both light-induced and light-quenched oscillatory behaviors. Preliminary mechanistic characterization with UV/vis absorption method and mass spectrometry suggests the formation of bromo-1,2-benzoquinone through the reaction between pyrocatechol and bromine.
Mechanisms of Dipolar Ortho/Para-H2O Conversion in Ice
Authors: Buntkowsky Gerd , Limbach Hans-Heinrich , Walaszek B. , Adamczyk A. , Xu Y. , Breitzke H. , Schweitzer A. , Gutmann T. , Wächtler M. , Amadeu N. , Tietze D. , Chaudret Bruno
Published: September 2008

In this paper a possible explanation for an unexpected ortho/para-water ratio in the gas clouds of comets is given. The description is based on the quantum-mechanical density matrix formalism and the spin temperature concept. Only the nuclear spin system is treated quantum-mechanically. Employing the model of a four spin system, created by two nearest neighbour water molecules, spin eigenstates and their dynamics under the influence of their mutual dipolar interactions are studied. It is shown that a fast conversion between ortho- and para-states occurs on a msec time scale, caused by the intermolecular homonuclear magnetic dipolar interaction. Moreover the spin eigenstates of water in an ice crystal are determined by magnetic dipolar interactions and are not given by normal ortho- and para-H2O states of gaseous water. As a result of this the spin temperature of gaseous water evaporated from ice depends strongly on its evaporation history and the ortho/para-ratio of water molecules are only an indirect measure of the temperature of ice crystals from where they descend. This result could explain the unexpected experimentally observed ortho/para-ratios in the clouds of comets.
Increasing 3α,5α-THP following inhibition of neurosteroid biosynthesis in the ventral tegmental area reinstates anti-anxiety, social, and sexual behavior of naturally receptive rats
Authors: Frye Cheryl A , Paris Jason J , Rhodes Madeline E
Published: September 2008

The progesterone metabolite and neurosteroid, 5α-pregnan-3α-ol-20-one (3α,5α-THP), has actions in the midbrain ventral tegmental area (VTA) to modulate lordosis, but its effects on other reproductively relevant behaviors are not well understood. Effects on exploration, anxiety, and social behavior resulting from inhibition of 3α,5α-THP formation, as well as 3α,5α-THP enhancement, were investigated in the midbrain VTA. Naturally sexually receptive, female rats (n=8–10/group) received infusions aimed at the midbrain VTA of vehicle, PK11195 (an inhibitor of neurosteroidogenesis), and/or indomethacin (an inhibitor of 3α,5α-THP formation from prohormones), and were subsequently infused with vehicle or FGIN 1-27 (a neurosteroidogenesis enhancer). The rats were then assessed in a behavioral battery that examined exploration (open field), anxiety (elevated plus maze), social (social interaction), and sexual (paced mating) behavior. Inhibition of 3α,5α-THP formation decreased exploratory, anti-anxiety, social, and sexual behavior, as well as midbrain 3α,5α-THP levels. Infusions of FGIN 1-27 following 3α,5α-THP inhibition restored these behaviors and midbrain 3α,5α-THP levels to those commensurate with control rats that had not been administered inhibitors. These findings suggest that 3α,5α-THP formation in the midbrain VTA may influence appetitive, as well as consummatory, aspects of mating behavior.
Effect of sowing dates on genetic components in six-rowed barley
Authors: Sharma Y. , Sharma S.
Published: September 2008

The genetics of yield and related traits was studied in barley (Hordeum vulgareL.) by means of 10 × 10 half-diallel progenies (F1and F2) at three sowing dates. An additive-dominance model fitted only for flag leaf area, spike length and 1000-grain weight at different sowing dates. Both additive (D) and dominance components (H1and H2) were significant for all the traits studied, indicating the preponderance of dominance components in controlling the inheritance for these traits. The value of (H1/D)1/2indicated over-dominance for all the traits except for flag leaf area. Values of ‘F’ indicated an excess of dominant alleles in the parents for all traits except for flag leaf area. The environmental component ‘E’ was significant for all traits. The ratio of H2/4H1indicated the symmetrical distribution of genes for all the traits studied. The value of h2/H2was less than one for all traits except for spike length, suggesting that a dominant gene was involved in controlling the inheritance of spike length, whereas multiple genes controlled the inheritance of the remaining traits. The heritability estimates were relatively moderate for flag leaf area and 1000-grain weight, but low for all other traits. However, epistatic interactions had an important role in the expression of other traits. Breeding methods such as bi-parental mating in early segregating generations or diallel selective mating may be advantageous to combine important yield component characters for a tangible advance in six-rowed barley.
Improving emergence of soybean ( Glycine max ) with straw mulch and other practices under normal and crusted soil conditions
Authors: Singh G. , Jolly R.
Published: September 2008

Poor emergence is a major problem in soybean [Glycine max(L.) Merrill]. A high emergence count leading to an optimum plant stand is a pre-requisite to obtain high grain yields. The results of three experiments on emergence in soybean are reported in this paper. Two field experiments were conducted to study the influence of wheat straw mulch, farmyard manure (FYM) mulch and seed soaking in water on the emergence of soybean under normal conditions. Immediately after sowing, covering rows of soybean with 3 t wheat straw ha−1(row mulch) or the whole plot with 6 t wheat straw ha−1(plot mulch) showed a profound effect on improving both the speed of emergence and the final emergence count. Row mulch with 5 t FYM ha−1only improved emergence in one year and its effect was not as great as with straw mulch. Soaking the seeds in water (on-farm seed priming) for 4, 8 or 16 h reduced emergence drastically. Another field experiment was conducted to study the effect of different mulching treatments or crust breaking in alleviating the crust effect of simulated rain on the emergence of soybean. Covering the soybean rows with 3 t wheat straw ha−1(row mulch) either before or after simulated rain improved the emergence count. Covering the soybean rows with 5 t FYM ha−1or breaking the crust also improved emergence, though the effects were not as good as with wheat straw mulch. The results suggest that the use of wheat straw mulch or FYM mulch can improve emergence in soybean in both normal and crusted soils, possibly by lowering the maximum soil temperature and conserving soil moisture.
The maximal operator of the Marcinkiewicz-Fejér means of the 2-dimensional Vilenkin-Fourier series
Authors: Blahota István , Goginava Ushangi
Published: September 2008

In this paper we prove that the maximal operator of the Marcinkiewicz-Fejér means of the 2-dimensional Vilenkin-Fourier series is not bounded from the Hardy spaceH2/3(G2) to the spaceL2/3(G2).
Fréchet approach to generalized second-order differentiability
Authors: Pastor Karel
Published: September 2008

The Fréchet approach to generalized second-order differentiability gives new sufficient optimality conditions for locally Lipschitz functions what seems to be useful for
C1,1
functions and functions possessing minimal subdifferential above all.
Nine lives in the music business
Authors: Laing Dave
Published: September 2008

Elton John’s American debut in 1970 was heralded by critics as the opening of a new, post-Sixties, era in popular music. This paper explores the backdrop to that debut through an analysis of John’s extremely varied experience in the British music industry of the 1960s. His ‘nine lives’ in the business ranged from classical music training and a job as a pub pianist to membership of a backing band for visiting American singers and professional songwriting. This combination of roles was almost untouched by the parallel growth in London of the rock underground and its counter-culture. Elton John, therefore, was a product of an Other 1960s, overdetermined by his prosthetic attachment to the acoustic piano in an era of electronic keyboard innovation. His pianism was drawn from classical, pub and 1950s rock ’n’ roll styles and his early stage act was heavily informed by Jerry Lee Lewis’s assault on the cultural prestige of the instrument.