Pressure-induced delocalization of photoexcited states in a semiconducting polymer.

We present broadband transient absorption spectroscopy on the fluorescent copolymer poly(9,9-dioctylfluorene-co-benzothiadiazole) under hydrostatic pressure of up to 75 kbar. We observe a strong reduction of the stimulated emission intensity under pressure, coupled with slower decay kinetics and reduced fluorescence intensity. These observations indicate increased delocalization of photogenerated singlet excitons, facilitated by an increased dielectric constant at high pressure. Spin triplet excitons, generated via an iridium complex-F8BT oligomer, show reduced lifetimes under pressure

Relative proximity of chromosome territories influences chromosome exchange partners in radiation-induced chromosome rearrangements in primary human bronchial epithelial cells

Copyright © 2013 The Authors. This article is made available through the Brunel Open Access Publishing Fund. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.Copyright © 2013 The Authors. It is well established that chromosomes exist in discrete territories (CTs) in interphase and are positioned in a cell-type specific probabilistic manner. The relative localisation of individual CTs within cell nuclei remains poorly understood, yet many cancers are associated with specific chromosome rearrangements and there is good evidence that relative territorial position influences their frequency of exchange. To examine this further, we characterised the complexity of radiation-induced chromosome exchanges in normal human bronchial epithelial (NHBE) cells by M-FISH analysis of PCC spreads and correlated the exchanges induced with their preferred interphase position, as determined by 1/2-colour 2D-FISH analysis, at the time of irradiation. We found that the frequency and complexity of aberrations induced were reduced in ellipsoid NHBE cells in comparison to previous observations in spherical cells, consistent with aberration complexity being dependent upon the number and proximity of damaged CTs, i.e. lesion proximity. To ask if particular chromosome neighbourhoods could be identified we analysed all radiation-induced pair-wise exchanges using SCHIP (statistics for chromosome interphase positioning) and found that exchanges between chromosomes (1;13), (9;17), (9;18), (12;18) and (16;21) all occurred more often than expected assuming randomness. All of these pairs were also found to be either sharing similar preferred positions in interphase and/or sharing neighbouring territory boundaries. We also analysed a human small cell lung cancer cell line, DMS53, by M-FISH observing the genome to be highly rearranged, yet possessing rearrangements also involving chromosomes (1;13) and (9;17). Our findings show evidence for the occurrence of non-random exchanges that may reflect the territorial organisation of chromosomes in interphase at time of damage and highlight the importance of cellular geometry for the induction of aberrations of varying complexity after exposure to both low and high-LET radiation.Department of Healt

Sleep practices among medical students in Pediatrics Department of University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria

Background: Medical students are a population who are at great risk of having bad sleep practice and hygiene due to demanding clinical and academic activities. Poor sleep practices are a disturbing and destabilizing phenomenon. It affects many people and can affect the quality of work, performance and education of medical students. Determining the sleep practices and behaviors could be useful to establish a systematic mental health curriculum in medical schools.Objectives: The objectives of this study is to describe sleep practices among undergraduate medical students in a Nigerian University.Materials and Methods: Sleep practices were investigated using a convenience sample of medical students from the University of Nigeria Teaching Hospital Ituku Ozalla, Enugu from October 2012 to February 2013.Results: A total number of participants enrolled were 241 consisting of 150 male and 90 female medical students. However, 222 (response rate: 92.1%) completed and returned the questionnaire. The median number of hours of night sleep on a weekday and weekend were 6 and 7 h respectively. There was a significant correlation between the number of hours of sleep and use of caffeine (Spearman r = −0.148, P < 0.0321). Ninety two (45.3%) had a sleep latency of 10-30 min while 157 (70.7%) woke up 1-2 times/night. Twenty five (11.3%) experience unusual sleep practices such as sleep walking, talking or night terrors.Conclusion: Medical students in our institution have varying degrees of sleeping practice and behavior and this may affect academic performance.Key words: Medical students, pediatrics, sleep practic

Cosmology in a brane-universe

This contribution presents the cosmological models with extra dimensions that have been recently elaborated, which assume that ordinary matter is confined on a surface, called brane, embedded in a higher dimensional spacetime.Comment: 12 pages; Invited review talk at the JENAM 2002 workshop on "The cosmology of extra dimensions and varying fundamental constants", Porto, Portugal, September 200

Pattern and clinical profile of children with complex cardiac anomaly at University of Nigeria Teaching Hospital, Ituku‑Ozalla, Enugu State, Nigeria

Background: Complex congenital cardiac abnormalities are rare among children and contribute to mortality and morbidity. The prevalence and pattern of presentation vary from lace to place.Materials and Methods: The objective of this study was to determine the clinical profile and pattern of presentation of complex congenital cardiac malformations among children attending a tertiary hospital in Enugu State. A cross‑sectional retrospective study in which a review of the records of children who attended the children outpatient clinic of University of Nigeria Teaching Hospital (UNTH), Ituku‑Ozalla, Enugu State over a 5‑year period (January 2007‑June 2012) was undertaken.Results: Thirty one thousand seven hundred and ninety‑five (31,795) children attended the outpatient clinic of the hospital over the study period, of these, 65 had cardiac diseases, from which 16 were found to have congenital complex cardiac abnormalities of various types, giving a prevalence of 0.05%. Complex abnormalities seen in these children are Tricuspid atresia with various associations, cor triatriatum, single ventricle, and large ASD (atrio‑septal defect) with complete AVCD, cor triatriatum sinistrum with cardiomyopathy, DORV (double outlet right ventricle) with left sided aorta, hypoplastic tricuspid valve with a PDA (patent ductus artriosus), TOF (tetralogy of fallot), prolapse of aortic valve, and pulmonary regurgitation. One of these complex cardiac anomalies presented with Turner’s syndrome and another with VACTERAL association.Conclusions: The results of this study show that 0.05% of children who presented at cardiology clinic of a teaching hospital in Enugu State had congenital complex cardiac abnormalities and that the commonest forms seen were those with cor triatriatum and TOF.Keywords: Abnormalities, children, complex congenital cardiac, Enugu, presentationNigerian Journal of Clinical Practice • Oct-Dec 2013 • Vol 16 • Issue

The Dawn of Open Access to Phylogenetic Data

The scientific enterprise depends critically on the preservation of and open access to published data. This basic tenet applies acutely to phylogenies (estimates of evolutionary relationships among species). Increasingly, phylogenies are estimated from increasingly large, genome-scale datasets using increasingly complex statistical methods that require increasing levels of expertise and computational investment. Moreover, the resulting phylogenetic data provide an explicit historical perspective that critically informs research in a vast and growing number of scientific disciplines. One such use is the study of changes in rates of lineage diversification (speciation - extinction) through time. As part of a meta-analysis in this area, we sought to collect phylogenetic data (comprising nucleotide sequence alignment and tree files) from 217 studies published in 46 journals over a 13-year period. We document our attempts to procure those data (from online archives and by direct request to corresponding authors), and report results of analyses (using Bayesian logistic regression) to assess the impact of various factors on the success of our efforts. Overall, complete phylogenetic data for ~60% of these studies are effectively lost to science. Our study indicates that phylogenetic data are more likely to be deposited in online archives and/or shared upon request when: (1) the publishing journal has a strong data-sharing policy; (2) the publishing journal has a higher impact factor, and; (3) the data are requested from faculty rather than students. Although the situation appears dire, our analyses suggest that it is far from hopeless: recent initiatives by the scientific community -- including policy changes by journals and funding agencies -- are improving the state of affairs

Mothers’ perception and management of abdominal colic in infants in Enugu, Nigeria

Background: Abdominal colic is common in infants but generally harmless. The exact aetiology is unknown but it has been associated with vicious cycle of crying and swallowing of air by the infant. The excessive crying associated with it can result in a lot of distress for family members creating unnecessary panics. We sought to find the perception and management of abdominal colic by mothers in Enugu.Objective: Objective of this study is to determine the perception and ‘home management’ of abdominal colic in infants by mothers in Enugu, south-east Nigeria and the factors associated with them.Materials and Methods: A cross-sectional survey involving 177 mothers that presented with their infants at the pediatric outpatient clinic of the University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu between June and November 2011. A pretested questionnaire was used after obtaining their consent.Results: A total of one hundred and seventy-seven mothers participated in this study. They were aged 20 to 60 years with mean age of 34 ± 7.3 years. Most of them (99.4%) believed that babies can have abdominal colic. While 41.3% attributed no problems to colic, the rest believed that it causes loose/greenish stools (12.4%), fever (16.4%) and vomiting (9.6%) etc. Most of the mothers (87.7%) do apply medications for colic which range from paracetamol (33.1%), Gbomoro (16.2%), teething powder (15.4%), salt water (13.2%), Buscopan (7.7%) and gripe water (4.6%).Conclusions: Mothers attribute symptoms of childhood illnesses to abdominal colic. This may have led to unnecessary and sometimes harmful management. There is need for health education of mothers and potential mothers.Key words: Abdominal colics, enugu, infant

Cerebrospinal fluid hypocretin (orexin) levels are elevated by play but are not raised by exercise and its associated heart rate, blood pressure, respiration or body temperature changes

Hypocretin (Hcrt) has been implicated in the control of motor activity and in respiration and cardiovascular changes. Loss of Hcrt in narcolepsy is linked to sleepiness and to cataplexy, a sudden loss of muscle tone which is triggered by sudden strong emotions. In the current study, we have compared the effects of treadmill running to yard play on cerebrospinal fluid (CSF) Hcrt level in normal dogs. We find that treadmill locomotion, at a wide range of speeds, does not increase Hcrt level beyond baseline, whereas yard play produces a substantial increase in Hcrt, even though both activities produce comparable increases in heart rate, respiration and body temperature. We conclude that motor and cardiovascular changes are not sufficient to elevate CSF levels of Hcrt and we hypothesize that the emotional aspects of yard play account for the observed increase in Hcrt

Perception of child adoption among parents/care‑givers of children attending pediatric outpatients’ clinics in Enugu, South East, Nigeria

Background: There has been an increasing interest by couples in child adoption due to its acceptability in recent times in our locale. The enactment of the Child’s Right Act in Nigeria has harmonized child adoption process across the nation. With the rising demand for babies from child care institutions by many Nigerian couples, there is need to ascertain their perception of child adoption.Objectives: To evaluate the perception of child adoption among parents/care‑givers of children attending Pediatric Clinics in Enugu.Materials and Methods: The parents and care‑givers of children attending pediatrics out‑patients clinics in Enugu, Enugu State, South East, Nigeria  served as the respondents. Two hundred and fifty nine of them were selected by convenience sampling method after obtaining their informed written consent. The data were obtained using semi ‑ structured questionnaire that was administered by an interviewer and subsequently analyzed using SPSS Version 15.0.Results: Many caregivers (respondents) (94.2.7%) had heard of child adoption and 79.2% of them understood the actual meaning of the term child adoption. About 1.9% of them had adopted previously. Majority of the respondents (73.87%) prefers to adopt a child during its neonatal age with a slight preference for adoption of male babies. 15.1% and 8.9% of the respondents gave private hospitals and middle men, respectively, as sources of child adoption. Knowledge of the Government adoption laws and process was generally below average (49.2%) among the respondents.Conclusion: Continued advocacy and public enlightenment campaigns should be strengthened in order to harmonize adoption process in our setting.Key words: Child adoption, parents/care‑givers, perceptio

The Underestimation Of Egocentric Distance: Evidence From Frontal Matching Tasks

There is controversy over the existence, nature, and cause of error in egocentric distance judgments. One proposal is that the systematic biases often found in explicit judgments of egocentric distance along the ground may be related to recently observed biases in the perceived declination of gaze (Durgin & Li, Attention, Perception, & Psychophysics, in press), To measure perceived egocentric distance nonverbally, observers in a field were asked to position themselves so that their distance from one of two experimenters was equal to the frontal distance between the experimenters. Observers placed themselves too far away, consistent with egocentric distance underestimation. A similar experiment was conducted with vertical frontal extents. Both experiments were replicated in panoramic virtual reality. Perceived egocentric distance was quantitatively consistent with angular bias in perceived gaze declination (1.5 gain). Finally, an exocentric distance-matching task was contrasted with a variant of the egocentric matching task. The egocentric matching data approximate a constant compression of perceived egocentric distance with a power function exponent of nearly 1; exocentric matches had an exponent of about 0.67. The divergent pattern between egocentric and exocentric matches suggests that they depend on different visual cues