Spatial and temporal variation of metal concentrations in adult honeybees (Apis mellifera L.)

Honeybees (Apis mellifera L.) have great potential for detecting and monitoring environmental pollution, given their wide-ranging foraging behaviour. Previous studies have demonstrated that concentrations of metals in adult honeybees were significantly higher at polluted than at control locations. These studies focused at a limited range of heavy metals and highly contrasting locations, and sampling was rarely repeated over a prolonged period. In our study, the potential of honeybees to detect and monitor metal pollution was further explored by measuring the concentration in adult honeybees of a wide range of trace metals, nine of which were not studied before, at three locations in the Netherlands over a 3-month period. The specific objective of the study was to assess the spatial and temporal variation in concentration in adult honeybees of Al, As, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ti, V and Zn. In the period of July–September 2006, replicated samples were taken at 2-week intervals from commercial-type beehives. The metal concentration in micrograms per gram honeybee was determined by inductive coupled plasma–atomic emission spectrometry. Significant differences in concentration between sampling dates per location were found for Al, Cd, Co, Cr, Cu, Mn Sr, Ti and V, and significant differences in average concentration between locations were found for Co, Sr and V. The results indicate that honeybees can serve to detect temporal and spatial patterns in environmental metal concentrations, even at relatively low levels of pollution

Aerobic nonylphenol degradation and nitro-nonylphenol formation by microbial cultures from sediments

Nonylphenol (NP) is an estrogenic pollutant which is widely present in the aquatic environment. Biodegradation of NP can reduce the toxicological risk. In this study, aerobic biodegradation of NP in river sediment was investigated. The sediment used for the microcosm experiments was aged polluted with NP. The biodegradation of NP in the sediment occurred within 8 days with a lag phase of 2 days at 30°C. During the biodegradation, nitro-nonylphenol metabolites were formed, which were further degraded to unknown compounds. The attached nitro-group originated from the ammonium in the medium. Five subsequent transfers were performed from original sediment and yielded a final stable population. In this NP-degrading culture, the microorganisms possibly involved in the biotransformation of NP to nitro-nonylphenol were related to ammonium-oxidizing bacteria. Besides the degradation of NP via nitro-nonylphenol, bacteria related to phenol-degrading species, which degrade phenol via ring cleavage, are abundantly present

Preserved Myocardial Deformation after Successful Coarctation Repair: A CMR Feature-Tracking Study

Contains fulltext : 190059.pdf (publisher's version ) (Open Access

Diagnosis, imaging and clinical management of aortic coarctation

Coarctation of the aorta (CoA) is a well-known congenital heart disease (CHD), which is often associated with several other cardiac and vascular anomalies, such as bicuspid aortic valve (BAV), ventricular septal defect, patent ductus arteriosus and aortic arch hypoplasia. Despite echocardiographic screening, prenatal diagnosis of CoA remains difficult. Most patients with CoA present in infancy with absent, delayed or reduced femoral pulses, a supine arm-leg blood pressure gradient (>20 mm Hg), or a murmur due to rapid blood flow across the CoA or associated lesions (BAV). Transthoracic echocardiography is the primary imaging modality for suspected CoA. However, cardiac magnetic resonance imaging is the preferred advanced imaging modality for non-invasive diagnosis and follow-up of CoA. Adequate and timely diagnosis of CoA is crucial for good prognosis, as early treatment is associated with lower risks of long-term morbidity and mortality. Numerous surgical and transcatheter treatment strategies have been reported for CoA. Surgical resection is the treatment of choice in neonates, infants and young children. In older children (>25 kg) and adults, transcatheter treatment is the treatment of choice. In the current era, patients with CoA continue to have a reduced life expectancy and an increased risk of cardiovascular sequelae later in life, despite adequate relief of the aortic stenosis. Intensive and adequate follow-up of the left ventricular function, valvular function, blood pressure and the anatomy of the heart and the aorta are, therefore, critical in the management of CoA. This review provides an overview of the current state-of-the-art clinical diagnosis, diagnostic imaging algorithms, treatment and follow-up of patients with CoA

Diagnosis, imaging and clinical management of aortic coarctation

Coarctation of the aorta (CoA) is a well-known congenital heart disease (CHD), which is often associated with several other cardiac and vascular anomalies, such as bicuspid aortic valve (BAV), ventricular septal defect, patent ductus arteriosus and aortic arch hypoplasia. Despite echocardiographic screening, prenatal diagnosis of CoA remains difficult. Most patients with CoA present in infancy with absent, delayed or reduced femoral pulses, a supine arm-leg blood pressure gradient (>20 mm Hg), or a murmur due to rapid blood flow across the CoA or associated lesions (BAV). Transthoracic echocardiography is the primary imaging modality for suspected CoA. However, cardiac magnetic resonance imaging is the preferred advanced imaging modality for non-invasive diagnosis and follow-up of CoA. Adequate and timely diagnosis of CoA is crucial for good prognosis, as early treatment is associated with lower risks of long-term morbidity and mortality. Numerous surgical and transcatheter treatment strategies have been reported for CoA. Surgical resection is the treatment of choice in neonates, infants and young children. In older children (>25 kg) and adults, transcatheter treatment is the treatment of choice. In the current era, patients with CoA continue to have a reduced life expectancy and an increased risk of cardiovascular sequelae later in life, despite adequate relief of the aortic stenosis. Intensive and adequate follow-up of the left ventricular function, valvular function, blood pressure and the anatomy of the heart and the aorta are, therefore, critical in the management of CoA. This review provides an overview of the current state-of-the-art clinical diagnosis, diagnostic imaging algorithms, treatment and follow-up of patients with CoA

Химическое окисление продуктов трансформации несимметричного диметилгидразина в воде

Окисление несимметричного диметилгидразина (НДМГ) при очистке воды имеет ряд недостатков, связанных с образованием побочных продуктов трансформации. Эффективность имеющихся методов очистки по отношению к продуктам трансформации НДМГ в настоящий момент мало изучена. В работе рассмотрена эффективность различных химических окислителей по отношению к основным продуктам трансформации НДМГ – 1-формил-2,2-диметилгидразина, диметиламиноацетонитрила, N-нитрозодиметиламина и 1-метил-1Н-1,2,4-триазола. В качестве окислителей изучены реактив Фентона, перманганат калия и нитрит натрия. Количественное определение загрязнителей проводили методом высокоэффективной жидкостной хроматографии. Продукты окисления определяли методом газовой хромато-масс-спектрометрии в сочетании с твердофазной микроэкстракцией. 1-Формил-2,2-диметилгидразин полностью окислялся, образуя различные соединения: N-формил-N-метилгидразон формальдегида в присутствии реактива Фентона, 1,4-дигидро-1,4-диметил-5Н-тетразол-5-он при действии перманганата калия и N-Метил-N-нитрометанамин в присутствии нитрита натрия. Добавление любого окислителя к раствору 1-формил-2,2-диметилгидразина приводило к образованию N-нитрозодиметиламина. Окисление диметиламиноацетонитрила протекало с образованием гидроксиацетонитрила, диметилформамида и 1,2,5-триметилпиррола. Спустя 30 дней после введения окислителей диметиламиноацетонитрил не обнаруживался в присутствии реактива Фентона и перманганата калия, но в образце с добавлением нитрита натрия его концентрация достигала 77,3 мг/л. В присутствии реактива Фентона, перманагната калия и нитрита натрия концентрация N-нитрозодиметиламина в образцах уменьшилась на 85, 80 и 50%, соответственно. В контрольной пробе концентрация N-нитрозодиметиламина снизилась на 50%, что свидетельствует о том, что нитрит натрия не влияет на содержание N-нитрозодиметиламина в воде. Только реактив Фентона позволил снизить концентрацию 1-метил-1Н-1,2,4-триазола в воде на 50% за 30 дней. В присутствии других окислителей концентрация 1-метил-1Н-1,2,4-триазола снизилась на 15-20%. В результате проведения исследований реактив Фентона показал себя наиболее эффективным окислителем.