1,348 research outputs found
Improved model for human induced vibrations of high-frequency floors
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe key UK design guidelines published by the Concrete Society and Concrete Centre for single human walking excitation of high-frequency floors were introduced more than 10 years ago. The corresponding walking force model is derived using a set of single footfalls recorded on a force plate and it features a deterministic approach which contradicts the stochastic nature of human-induced loading, including intra- and inter- subject variability. This paper presents an improved version of this force model for high-frequency floors with statistically defined parameters derived using a comprehensive database of walking force time histories, comprising multiple successive footfalls that are continuously measured on an instrumented treadmill. The improved model enables probability-based prediction of vibration levels for any probability of non-exceedance, while the existing model allows for vibration prediction related to 75% probability of non-exceedance for design purposes. Moreover, the improved model shifts the suggested cut-off frequency between low- and high-frequency floors from 10 Hz to 14 Hz. This is to account for higher force harmonics that can still induce the resonant vibration response and to avoid possible significant amplification of the vibration response due to the near-resonance effect. Minor effects of near-resonance are taken into account by a damping factor. The performance of the existing and the improved models is compared against numerical simulations carried out using a finite element model of a structure and the treadmill forces. The results show that while the existing model tends to overestimate or underestimate the vibration levels depending on the pacing rate, the new model provides statistically reliable estimations of the vibration responses. Hence, it can be adopted in a new generation of the design guidelines featuring a probabilistic approach to vibration serviceability assessment of high-frequency floors.The authors would like to acknowledge the College of Engineering, Mathematics and Physical Sciences in the University of Exeter for the financial support provided for the PhD programme of the first author. The authors would also like to acknowledge the UK Engineering and Physical Sciences Research (EPSRC) for the following research grants:
Platform Grant EP/G061130/2 (Dynamic performance of large civil engineering structures: an integrated approach to management, design and assessment) and
Standard Grant EP/I029567/1 (Synchronization in dynamic loading due to multiple pedestrians and occupants of vibration-sensitive structures)
Chromosomal study in newborn infants with congenital anomalies in Assiut University hospital: Cross-sectional study
In 40–60% of congenital malformations, the cause is unknown. Genetic factors account for approximately 15%; environmental factors produce approximately 10%; a combination of genetic and environmental influences produces 20–25%. The study aims to document prevalenceand patterns of congenital malformations detected at birth in Assiut University hospital and clarify underlying chromosomal abnormalities of such malformations. Also possible predisposing factors will be studied.Newborns with apparent congenital anomalies were selected from 5000 newborn infants delivered consecutively at the department of Obstetrics and Gynecology within 7 months. Full maternal history, family history, perinatal history, pedigree construction as well as clinical examinations andinvestigations including karyotype were done. Congenital anomalies were found in 103 cases with a prevalence of 2.06% with male to female ratio of 1.7:1. Skeletal system anomalies had the highestfrequency (37.9%), followed in descending order by chromosomal abnormalities (27.2%), circulatory system anomalies (22.3%), central nervous system (CNS) anomalies (19.4%), genital organs anomalies (16.5%), gastrointestinal tract (GIT) anomalies (14.6%), eye and ear anomalies (8.7%), and lastly urinary system and others anomalies in 3.9% each. Breech presentation, perinatal asphyxia, incubator admission and the need for resuscitation were significantly associated with the presence of congenital anomalies. Higher prevalence of congenital anomalies was observed in neonatesof grand multiparous women, diabetic mothers delivery by CS, cases with oligohydramnios and with positive consanguinity. Chromosomal abnormalities were found in 28 cases (27.18% of malformed cases) (5.6/1000). Numerical abnormalities were found in 22 cases (21.35%) (4.4/1000), Down syndrome in 16 cases, Edward syndrome in two cases, Patau syndrome in one case and Turner syndrome (monosomy) inthree cases. Structural abnormalities were present in six cases (5.83%) (1.2/1000), Down syndrome in two cases, Turner syndrome in two cases, balanced translocation [(12;13)(q15;q34)] with dysmorphic features and undescended testis in one case and deletion 9(q11;q31) with disorder of sex development in one case. To conclude karyotype should not be done routinely for all malformed cases as many of them are due to genetic syndromes. So, it is more useful to consult expert dysmorphologists for proper syndrome identification and for the decision to use more recent molecular techniques for diagnosis
Computer Modeling of Platinum Reforming Reactors
Usually, the reformate that is leaving any stage of the platinum reforming reactors in terms of hydrocarbon composition is assessed by laboratory analysis. The ideal composition can only be tested through theoretical means, which in most cases is avoided because of long computation time involved. This paper, instead of using a theoretical approach has considered a computer model as means of assessing the reformate composition for three-stage fixed bed reactors in platforming unit. This is done by identifying many possible hydrocarbon transformation reactions that are peculiar to the process unit, identify the operating data, mathematically model and programme their reaction rate equations using QBasic language. In this article outlet product rate of 311363.59 kg/hr in the first, second and third reactor was obtained by modeling 275 m3/h inlet feed rate of Bayton Rouge Naphtha in the Kaduna Refinery. A manual or theoretical calculated value of 311145.22 kg/hr of outlet product rate was obtained showing a slight deviation of 0.9%. The authors are convinced that the written computer model could be applied in the process unit because it is accurate and less time consuming
The changes in various hydroxyproline fractions in aortic tissue of rabbits are closely related to the progression of atherosclerosis
<p>Abstract</p> <p>Background</p> <p>The most important function of collagen and elastin is to induce several mechanical parameters which are known to play a dominant role in governing mechanical properties of the blood vessels. The aortic tissue of rabbit is one of the important sources of collagen and elastin. The effects of high fat diet (HFD) on the hydroxyproline (Hyp) fractions in serum and aortic tissues of rabbits and collagen content in the aortic tissues of rabbits have not been documented before. The present study was undertaken to investigate the changes in Hyp fractions in serum and aortic tissues of rabbits and collagen content in the aortic tissues of rabbits during the progression of atherosclerosis. The atherosclerotic model used in this study was the New Zealand white rabbit (male; 12 weeks old). Twenty five rabbits were individually caged, and divided into control group (NOR; n = 10) and HFD group (CHO; n = 15). The control group was fed (100 g/day) of normal (NOR) diet for a period of 15 weeks. The HFD group was fed normal diet supplemented with 1.0% cholesterol plus 1.0% olive oil (100 g/day) for the same period of time.</p> <p>Results</p> <p>We found that the TC, LDLC, and TG (mg/dl) were significantly (p < 0.001) increased in HFD rabbits compared with control rabbits with percentage normalized changes of 1198%, 1591%, and 710%, respectively. The peptide-bound Hyp in the serum was significantly (P < 0.05) increased in HFD rabbits compared with control rabbits with percentage normalized change of 517% while it significantly (P < 0.01) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 65%. The protein-bound Hyp in the serum was significantly (P < 0.01) increased in HFD rabbits compared with control rabbits with percentage normalized change of 100%; the protein-bound Hyp in the aortic tissues of control rabbits was 235.30 ± 55.14 (Mean ± SD) while it was not detectable (ND) in HFD rabbits. Total serum Hyp showed no significant (P < 0.05) change in HFD rabbits compared with control rabbits while it was significantly (P < 0.05) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 73%. The total collagen was significantly (p < 0.01) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 73% which was supported by histological study.</p> <p>Conclusions</p> <p>These results suggest that percentage decrease in various Hyp fractions in aortic tissue of HFD rabbits are closely related to percentage decrease of collagen content in aortic tissues of HFD rabbits. These results also suggest that it may be possible to use the changes in various Hyp fractions in aortic tissues of rabbits as an important risk factor during the progression of atherosclerosis.</p
Antibiogram of pharyngeal isolates of children with pharyngotonsillitis in a specialist hospital in Gusau, North-Western Nigeria
Pharyngotonsillitis is one of the common childhood infections caused by bacteria in 30 to 40% of cases. Bacterial causes are important due to the non suppurative sequalae caused by Streptococcus pyogenes and also associated complications. These microorganisms undergo constant changes and antibiotic resistance have been reported. Objective: To document organisms isolated from throat swab microscopy and culture with their antibiotic susceptibility pattern in children diagnosed with pharyngotonsillitis. Methodology: This was a retrospective analysis of throat swabs microscopy, culture and sensitivity results of children aged 0-13 years with a diagnosis of pharyngotonsillitis over a four-year period. Results: Of the 144 results reviewed; 120 samples yielded 122 isolates, giving a culture positive yield of 83.3%. Males were 81 (56.2%) with a M:F ratio of 1.3:1. Majority of the children were under fives (58.3%). Gram positive organisms were 118 (96.7%), with Streptococcus pyogenes being the commonest organism isolated (79.5%), followed by Staphylococcus aureus (13.9%). Gentamicin (85.0%), Ofloxacin (64.2%) and Augmentin (51.7%) had the highest susceptibility rate, while the least was seen with Cefixime, Tetracycline, Levofloxacin and Netillin. Streptococcus pyogenes and Staphylococcus aureuswere susceptible to Gentamicin and Ofloxacin, while all the Streptococcus pneumoniae were susceptible to Gentamicin. Multi drug resistance was seen with Providencia spp and Serratia marcescens. Conclusion: Streptococcus pyogenes was the commonest organism and Gentamicin, Ofloxacin and Augmentin were the antibiotics with the highest susceptibility. Gram negative organisms display high rate of multidrug resistance. Gentamicin could be considered as an option or an adjunct in the treatment of pharyngotonsilliti
A novel martial arts-based virtuality reality intervention modulates pain and the pain neuromatrix in patients with opioid use disorder
Background: Standard-of-care for opioid use disorder (OUD) includes medication and counseling. However, there is an unmet need for complementary approaches to treat OUD patients coping with pain; furthermore, few studies have probed neurobiological features of pain or its management during OUD treatment. This preliminary study examines neurobiological and behavioral effects of a martial arts-based intervention in patients undergoing methadone maintenance treatment (MMT).
Methods: Fifteen (11 female) MMT patients completed a virtual reality, therapist-guided martial arts intervention that included breathing and relaxation exercises; sessions were scheduled twice weekly. Assessments included functional magnetic resonance imaging (fMRI) of pain neuromatrix activation and connectivity (pre- and post-intervention), saliva cortisol and C-reactive protein (CRP) at baseline and weeks 4, 8 and 12; and self-reported pain and affective symptoms before and after each intervention session.
Results: After each intervention session (relative to pre-session), ratings of pain, opioid craving, anxiety and depression (but not anger) decreased. Saliva cortisol (but not CRP) levels decreased from pre- to post-session. From pre- to post-intervention fMRI assessments, pain task-related left postcentral gyrus (PCG) activation decreased. Higher baseline cortisol levels were associated with greater post-intervention pain task-related insular activation. At baseline, PCG showed positive connectivity with other regions of the pain neuromatrix, but this pattern changed post-intervention.
Conclusions: These preliminary findings demonstrate feasibility, therapeutic promise, and brain basis of a martial arts-based intervention for OUD patients undergoing MMT
Comparing computer-generated and pathologist-generated tumour segmentations for immunohistochemical scoring of breast tissue microarrays
BACKGROUND: Tissue microarrays (TMAs) have become a valuable resource for biomarker expression in translational research. Immunohistochemical (IHC) assessment of TMAs is the principal method for analysing large numbers of patient samples, but manual IHC assessment of TMAs remains a challenging and laborious task. With advances in image analysis, computer-generated analyses of TMAs have the potential to lessen the burden of expert pathologist review. METHODS: In current commercial software computerised oestrogen receptor (ER) scoring relies on tumour localisation in the form of hand-drawn annotations. In this study, tumour localisation for ER scoring was evaluated comparing computer-generated segmentation masks with those of two specialist breast pathologists. Automatically and manually obtained segmentation masks were used to obtain IHC scores for thirty-two ER-stained invasive breast cancer TMA samples using FDA-approved IHC scoring software. RESULTS: Although pixel-level comparisons showed lower agreement between automated and manual segmentation masks (κ=0.81) than between pathologists' masks (κ=0.91), this had little impact on computed IHC scores (Allred; [Image: see text]=0.91, Quickscore; [Image: see text]=0.92). CONCLUSIONS: The proposed automated system provides consistent measurements thus ensuring standardisation, and shows promise for increasing IHC analysis of nuclear staining in TMAs from large clinical trials
Climate change and anthropogenic intervention impact on the hydrologic anomalies in a semi-arid area : lower Zab river basin, Iraq
Climate change impact, drought phenomena and anthropogenic stress are of increasing apprehension for water resource managers and strategists, particularly in arid regions. The current study proposes a generic methodology to evaluate the potential impact of such changes at a basin scale. The Lower Zab River Basin located in the north of Iraq has been selected for illustration purposes. The method has been developed through evaluating changes during normal hydrological years to separate the effects of climate change and estimate the hydrologic abnormalities utilising Indicators of Hydrologic Alteration. The meteorological parameters were perturbed by applying adequate delta perturbation climatic scenarios. Thereafter, a calibrated rainfall-runoff model was used for streamflow simulations. Findings proved that climate change has a more extensive impact on the hydrological characteristics of the streamflow than anthropogenic intervention (i.e. the construction of a large dam in the catchment). The isolated baseflow is more sensitive to the precipitation variations than to the variations of the potential evapotranspiration. The current hydrological anomalies are expected to continue. This comprehensive basin study demonstrates how climate change impact, anthropogenic intervention as well as hydro-climatic drought and hydrological anomalies can be evaluated with a new methodology
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