Levels of Heavy Metals in Drinking Water, Cosmetics and Fruit Juices from Selected Areas in Dar Es Salaam

Heavy metals were determined in samples of drinking water, cosmetics (nail polish, lip glosses and hair dye) and fresh fruit juices in Dar es Salaam. The samples were analyzed using Atomic Absorption Spectrometry (AAS) after digestion with concentrated acids, filtration and dilution. Lead, zinc and iron were detected in the water samples and the concentration ranges were below detection limit (BDL) to 0.114, 0.01 to 1.47 and 0.027 to 0.39 mg/L, respectively, whereas cadmium was not detected. The concentrations of lead in 70.83% of the samples exceeded the WHO permissible limit, implying that the water in most of the areas was not suitable for human consumption. Lead, zinc, and cadmium were detected in all the cosmetics at concentrations ranging from 6.6 to 37400, 21.5 to 2600, and up to 0.25 mg/kg, respectively. Most of the concentrations of lead in cosmetics exceeded the EU/US permissible limits. The continued use of products containing such heavy metals may increase the body intake of the metals and cause harmful effects. Only copper was detected in the fruit juices and the water used for their preparations at concentrations ranging from 0.008 ± 0.003 to 0.215 ± 0.014 mg/L, which were below the WHO permissible limit. Keywords: Heavy metals, drinking water, tap water, cosmetics, fruit juice, Tanzani

Inferring muscle functional roles of the ostrich pelvic limb during walking and running using computer optimization

Owing to their cursorial background, ostriches (Struthio camelus) walk and run with high metabolic economy, can reach very fast running speeds and quickly execute cutting manoeuvres. These capabilities are believed to be a result of their ability to coordinate muscles to take advantage of specialized passive limb structures. This study aimed to infer the functional roles of ostrich pelvic limb muscles during gait. Existing gait data were combined with a newly developed musculoskeletal model to generate simulations of ostrich walking and running that predict muscle excitations, force and mechanical work. Consistent with previous avian electromyography studies, predicted excitation patterns showed that individual muscles tended to be excited primarily during only stance or swing. Work and force estimates show that ostrich gaits are partially hip-driven with the bi-articular hip–knee muscles driving stance mechanics. Conversely, the knee extensors acted as brakes, absorbing energy. The digital extensors generated large amounts of both negative and positive mechanical work, with increased magnitudes during running, providing further evidence that ostriches make extensive use of tendinous elastic energy storage to improve economy. The simulations also highlight the need to carefully consider non-muscular soft tissues that may play a role in ostrich gait

Reducing the size and number of linear programs in a dynamic Gr\"obner basis algorithm

The dynamic algorithm to compute a Gr\"obner basis is nearly twenty years old, yet it seems to have arrived stillborn; aside from two initial publications, there have been no published followups. One reason for this may be that, at first glance, the added overhead seems to outweigh the benefit; the algorithm must solve many linear programs with many linear constraints. This paper describes two methods of reducing the cost substantially, answering the problem effectively.Comment: 11 figures, of which half are algorithms; submitted to journal for refereeing, December 201

Outdoor music festivals: Cacophonous consumption or melodious moderation?

Large outdoor music festivals have emerged as part of a general expansion of licensed recreational activities, but in research terms they have been largely impenetrable due to commercial sensitivities. These sensitivities notwithstanding, the number and scale of such events necessitate a greater understanding of alcohol and drug use and the potential to promote normative protective behaviours in this context. This study examines self-reported alcohol and drug behaviours of 1589 attendees at a music festival in Scotland during the summer of 2008. Similarities between the outdoor rock music festivals and the dance club scene are considered alongside the challenges associated with risk reduction in these settings. Results show that alcohol was consumed by the majority of samples; however, negative consequences were reported by a minority of respondents, suggesting evidence of controlled hedonism within a situation traditionally associated with unrestrained excess. Similarly, the majority of samples did not use drugs. The majority also report a number of self-regulating protective behaviours suggesting that alcohol and drug use is contained within a developing social culture of ‘controlled intoxication’. Results further suggest that although music festivals are transitory events, there is a degree of consistency amongst attendees. Music festivals may therefore be atypical but potentially effective environments to increase protective behaviours using normative messaging and modern communications media. This study was resourced exclusively by local alcohol and drug partnerships

Endovenous laser ablation therapy in children: applications and outcomes

BACKGROUND: Endovenous laser ablation is well recognized as the first-line treatment for superficial venous reflux with varicose veins in adults. It is not widely reported and is not an established practice in pediatric patients. OBJECTIVE: To illustrate a variety of pediatric venous conditions in which endovenous laser ablation can be utilized and to demonstrate its feasibility and safety in children. MATERIALS AND METHODS: We conducted a retrospective review of endovenous laser ablation procedures performed between January 2007 and July 2014 at two large pediatric institutions. RESULTS: We included 35 patients (17 males) who underwent endovenous laser ablation to 43 veins. Median age at first treatment was 14 years (range: 3-18 years). Median weight was 56 kg (range: 19-97 kg). Underlying diagnoses were common venous malformation (15), Klippel-Trenaunay syndrome (8), superficial venous reflux with varicose veins (5), verrucous hemangioma-related phlebectasia (4), venous varix (2) and arteriovenous fistula (1). The most common aim of treatment was to facilitate sclerotherapy. Thirty-four patients had treatment in the lower limbs and one patient in an upper limb. Ten of the veins treated with endovenous laser ablation had an additional procedure performed to close the vein. Complications attributable to endovenous laser ablation occurred in two patients (6%). One patient experienced post-procedural pain and one patient developed a temporary sensory nerve injury. Median clinical follow-up was 13 months (range: 28 days-5.7 years). The aim of the treatment was achieved in 29 of the 35 (83%) patients. CONCLUSION: Endovenous laser ablation is technically feasible and safe in children. It can be used in the management of a range of pediatric venous diseases with good outcomes

Safeguarding children in dentistry: 1. Child protection training, experience and practice of dental professionals with an interest in paediatric dentistry

* Few dental professionals with child protection training have experience of making referrals. * There is a wide gap in practice between recognising signs of child abuse and neglect and responding effectively. * This may indicate missed opportunities to save children from continuing abuse. * There is a need for improved child protection information, support and training for dental professionals. Abstract Following several highly publicised inquiries into the deaths of children from abuse and neglect, there has been much recent interest in the role and responsibility of all health professionals to protect children at risk of maltreatment. The findings of a postal questionnaire, sent in March 2005 to 789 dentists and dental care professionals with an interest in paediatric dentistry working in varied settings in the UK, are presented in a two-part report and discussed in the context of current multi-agency good practice in safeguarding and promoting the welfare of children. This first part explores reported child protection training, experience and practice. There was a significant gap between recognising signs of abuse and responding effectively: 67% of respondents had suspected abuse or neglect of a child patient at some time in their career but only 29% had ever made a child protection referral. The dental profession is alerted to the need to ensure necessary appropriate action to safeguard children is always taken when child abuse or neglect are suspected

Developing a Relative Humidity Correction for Low-Cost Sensors Measuring Ambient Particulate Matter.

There is increasing concern about the health impacts of ambient Particulate Matter (PM) exposure. Traditional monitoring networks, because of their sparseness, cannot provide sufficient spatial-temporal measurements characteristic of ambient PM. Recent studies have shown portable low-cost devices (e.g., optical particle counters, OPCs) can help address this issue; however, their application under ambient conditions can be affected by high relative humidity (RH) conditions. Here, we show how, by exploiting the measured particle size distribution information rather than PM as has been suggested elsewhere, a correction can be derived which not only significantly improves sensor performance but which also retains fundamental information on particle composition. A particle size distribution⁻based correction algorithm, founded on κ -Köhler theory, was developed to account for the influence of RH on sensor measurements. The application of the correction algorithm, which assumed physically reasonable κ values, resulted in a significant improvement, with the overestimation of PM measurements reduced from a factor of ~5 before correction to 1.05 after correction. We conclude that a correction based on particle size distribution, rather than PM mass, is required to properly account for RH effects and enable low cost optical PM sensors to provide reliable ambient PM measurements

Noise auto-correlation spectroscopy with coherent Raman scattering

Ultrafast lasers have become one of the most powerful tools in coherent nonlinear optical spectroscopy. Short pulses enable direct observation of fast molecular dynamics, whereas broad spectral bandwidth offers ways of controlling nonlinear optical processes by means of quantum interferences. Special care is usually taken to preserve the coherence of laser pulses as it determines the accuracy of a spectroscopic measurement. Here we present a new approach to coherent Raman spectroscopy based on deliberately introduced noise, which increases the spectral resolution, robustness and efficiency. We probe laser induced molecular vibrations using a broadband laser pulse with intentionally randomized amplitude and phase. The vibrational resonances result in and are identified through the appearance of intensity correlations in the noisy spectrum of coherently scattered photons. Spectral resolution is neither limited by the pulse bandwidth, nor sensitive to the quality of the temporal and spectral profile of the pulses. This is particularly attractive for the applications in microscopy, biological imaging and remote sensing, where dispersion and scattering properties of the medium often undermine the applicability of ultrafast lasers. The proposed method combines the efficiency and resolution of a coherent process with the robustness of incoherent light. As we demonstrate here, it can be implemented by simply destroying the coherence of a laser pulse, and without any elaborate temporal scanning or spectral shaping commonly required by the frequency-resolved spectroscopic methods with ultrashort pulses.Comment: To appear in Nature Physic

Regional regulation of transcription in the chicken genome

<p>Abstract</p> <p>Background</p> <p>Over the past years, the relationship between gene transcription and chromosomal location has been studied in a number of different vertebrate genomes. Regional differences in gene expression have been found in several different species. The chicken genome, as the closest sequenced genome relative to mammals, is an important resource for investigating regional effects on transcription in birds and studying the regional dynamics of chromosome evolution by comparative analysis.</p> <p>Results</p> <p>We used gene expression data to survey eight chicken tissues and create transcriptome maps for all chicken chromosomes. The results reveal the presence of two distinct types of chromosomal regions characterized by clusters of highly or lowly expressed genes. Furthermore, these regions correlate highly with a number of genome characteristics. Regions with clusters of highly expressed genes have higher gene densities, shorter genes, shorter average intron and higher GC content compared to regions with clusters of lowly expressed genes. A comparative analysis between the chicken and human transcriptome maps constructed using similar panels of tissues suggests that the regions with clusters of highly expressed genes are relatively conserved between the two genomes.</p> <p>Conclusions</p> <p>Our results revealed the presence of a higher order organization of the chicken genome that affects gene expression, confirming similar observations in other species. These results will aid in the further understanding of the regional dynamics of chromosome evolution.</p> <p>The microarray data used in this analysis have been submitted to NCBI GEO database under accession number GSE17108. The reviewer access link is: <url>http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?token=tjwjpscyceqawjk&acc=GSE17108</url></p

Comparison of Short-Term Estrogenicity Tests for Identification of Hormone-Disrupting Chemicals

The aim of this study was to compare results obtained by eight different short-term assays of estrogenlike actions of chemicals conducted in 10 different laboratories in five countries. Twenty chemicals were selected to represent direct-acting estrogens, compounds with estrogenic metabolites, estrogenic antagonists, and a known cytotoxic agent. Also included in the test panel were 17β-estradiol as a positive control and ethanol as solvent control. The test compounds were coded before distribution. Test methods included direct binding to the estrogen receptor (ER), proliferation of MCF-7 cells, transient reporter gene expression in MCF-7 cells, reporter gene expression in yeast strains stably transfected with the human ER and an estrogen-responsive reporter gene, and vitellogenin production in juvenile rainbow trout. 17β-Estradiol, 17α-ethynyl estradiol, and diethylstilbestrol induced a strong estrogenic response in all test systems. Colchicine caused cytotoxicity only. Bisphenol A induced an estrogenic response in all assays. The results obtained for the remaining test compounds—tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol dodecylethoxylate, butylbenzylphthalate, dibutylphthalate, methoxychlor, o,p′-DDT, p,p′-DDE, endosulfan, chlomequat chloride, and ethanol—varied among the assays. The results demonstrate that careful standardization is necessary to obtain a reasonable degree of reproducibility. Also, similar methods vary in their sensitivity to estrogenic compounds. Thus, short-term tests are useful for screening purposes, but the methods must be further validated by additional interlaboratory and interassay comparisons to document the reliability of the methods