Molecular evidence for sediment nitrogen fixation in a temperate New England estuary

Primary production in coastal waters is generally nitrogen (N) limited with denitrification outpacing nitrogen fixation (N2-fixation). However, recent work suggests that we have potentially underestimated the importance of heterotrophic sediment N2-fixation in marine ecosystems. We used clone libraries to examine transcript diversity of nifH (a gene associated with N2-fixation) in sediments at three sites in a temperate New England estuary (Waquoit Bay, Massachusetts, USA) and compared our results to net sediment N2 fluxes previously measured at these sites. We observed nifH expression at all sites, including a site heavily impacted by anthropogenic N. At this N impacted site, we also observed mean net sediment N2-fixation, linking the geochemical rate measurement with nifH expression. This same site also had the lowest diversity (non-parametric Shannon = 2.75). At the two other sites, we also detected nifH transcripts, however, the mean N2 flux indicated net denitrification. These results suggest that N2-fixation and denitrification co-occur in these sediments. Of the unique sequences in this study, 67% were most closely related to uncultured bacteria from various marine environments, 17% to Cluster III, 15% to Cluster I, and only 1% to Cluster II. These data add to the growing body of literature that sediment heterotrophic N2-fixation, even under high inorganic nitrogen concentrations, may be an important yet overlooked source of N in coastal systems

Characterisation of the proximal airway squamous metaplasia induced by chronic tobacco smoke exposure in spontaneously hypertensive rats

<p>Abstract</p> <p>Background</p> <p>Continuous exposure to tobacco smoke (TS) is a key cause of chronic obstructive pulmonary disease (COPD), a complex multifactorial disease that is difficult to model in rodents. The spontaneously hypertensive (SH) rat exhibits several COPD-associated co-morbidities such as hypertension and increased coagulation. We have investigated whether SH rats are a more appropriate animal paradigm of COPD.</p> <p>Methods</p> <p>SH rats were exposed to TS for 6 hours/day, 3 days/week for 14 weeks, and the lung tissues examined by immunohistochemistry.</p> <p>Results</p> <p>TS induced a CK13-positive squamous metaplasia in proximal airways, which also stained for Ki67 and p63. We hypothesise that this lesion arises by basal cell proliferation, which differentiates to a squamous cell phenotype. Differences in staining profiles for the functional markers CC10 and surfactant D, but not phospho-p38, indicated loss of ability to function appropriately as secretory cells. Within the parenchyma, there were also differences in the staining profiles for CC10 and surfactant D, indicating a possible attempt to compensate for losses in proximal airways. In human COPD sections, areas of CK13-positive squamous metaplasia showed sporadic p63 staining, suggesting that unlike the rat, this is not a basal cell-driven lesion.</p> <p>Conclusion</p> <p>This study demonstrates that although proximal airway metaplasia in rat and human are both CK13+ and therefore squamous, they potentially arise by different mechanisms.</p

Does the availability of snack foods in supermarkets vary internationally?

BackgroundCross-country differences in dietary behaviours and obesity rates have been previously reported. Consumption of energy-dense snack foods and soft drinks are implicated as contributing to weight gain, however little is known about how the availability of these items within supermarkets varies internationally. This study assessed variations in the display of snack foods and soft drinks within a sample of supermarkets across eight countries.MethodsWithin-store audits were used to evaluate and compare the availability of potato chips (crisps), chocolate, confectionery and soft drinks. Displays measured included shelf length and the proportion of checkouts and end-of-aisle displays containing these products. Audits were conducted in a convenience sample of 170 supermarkets across eight developed nations (Australia, Canada, Denmark, Netherlands, New Zealand, Sweden, United Kingdom (UK), and United States of America (US)).ResultsThe mean total aisle length of snack foods (adjusted for store size) was greatest in supermarkets from the UK (56.4 m) and lowest in New Zealand (21.7 m). When assessed by individual item, the greatest aisle length devoted to chips, chocolate and confectionery was found in UK supermarkets while the greatest aisle length dedicated to soft drinks was in Australian supermarkets. Only stores from the Netherlands (41%) had less than 70% of checkouts featuring displays of snack foods or soft drinks.ConclusionWhilst between-country variations were observed, overall results indicate high levels of snack food and soft drinks displays within supermarkets across the eight countries. Exposure to snack foods is largely unavoidable within supermarkets, increasing the likelihood of purchases and particularly those made impulsively.<br /

Molecular Acoustic Angiography: A New Technique for High-resolution Superharmonic Ultrasound Molecular Imaging

Ultrasound molecular imaging utilizes targeted microbubbles to bind to vascular targets such as integrins, selectins, and other extracellular binding domains. After binding, these microbubbles are typically imaged using low pressures and multi-pulse imaging sequences. In this article, we present an alternative approach for molecular imaging using ultrasound which relies on superharmonic signals produced by microbubble contrast agents. Bound bubbles were insonified near resonance using a low frequency (4 MHz) and superharmonic echoes were received at high frequencies (25–30 MHz). While this approach was observed to produce declining image intensity during repeated imaging in both in vitro and in vivo experiments due to bubble destruction, the feasibility of superharmonic molecular imaging was demonstrated for transmit pressures which are sufficiently high to induce shell disruption in bound microbubbles. This approach was validated using microbubbles targeted to the αvβ3 integrin in a rat fibrosarcoma model (n=5), and combined with superharmonic images of free microbubbles to produce high contrast, high resolution 3D volumes of both microvascular anatomy and molecular targeting. Image intensity over repeated scans and the effect of microbubble diameter were also assessed in vivo, indicating that larger microbubbles yield increased persistence in image intensity. Using ultrasound-based acoustic angiography images rather than conventional B-mode ultrasound to provide the underlying anatomical information facilitates anatomical localization of molecular markers. Quantitative analysis of relationships between microvasculature and targeting information indicated that most targeting occurred within 50 µm of a resolvable vessel (>100 µm diameter). The combined information provided by these scans may present new opportunities for analyzing relationships between microvascular anatomy and vascular targets, subject only to limitations of the current mechanically-scanned system and microbubble persistence to repeated imaging at moderate mechanical indices

Validation and Safety Approval of a Dual-Mode Head Coil for pTx Applications In Vivo at 7 Tesla

Following regulatory approval of single-transmit MRI at 7 tesla, there is a rapidly growing interest in clinical MRI at this field strength. However, the wider use of diagnostic MRI at 7T will require imaging in parallel-transmit (pTx) mode to reduce B1+ inhomogeneity. Previous work introduced a dual-mode head coil that operates in both transmit modes and this study investigates the use of this coil for the pTx case. It also describes the safety procedure that was followed to ensure safe operation for human scanning using the real-time SAR supervision on a commercial scanner

The thorny issue of choosing outcome measures for aphasia therapy trials: A comparison of discourse and aphasia battery outcomes following Multi-modality and Constraint Induced aphasia therapy

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Development of reverse-transcription PCR techniques to analyse the density and sex ratio of gametocytes in genetically diverse Plasmodium chabaudi infections

We have developed cross-genotype and genotype-specific quantitative reverse-transcription PCR (qRT-PCR) assays to detect and quantify the number of parasites, transmission stages (gametocytes) and male gametocytes in blood stage Plasmodium chabaudi infections. Our cross-genotype assays are reliable, repeatable and generate counts that correlate strongly (R(2)s > 90%) with counts expected from blood smears. Our genotype-specific assays can distinguish and quantify different stages of genetically distinct parasite clones (genotypes) in mixed infections and are as sensitive as our cross-genotype assays. Using these assays we show that gametocyte density and gametocyte sex ratios vary during infections for two genetically distinct parasite lines (genotypes) and present the first data to reveal how sex ratio is affected when each genotype experiences competition in mixed-genotype infections. Successful infection of mosquito vectors depends on both gametocyte density and their sex ratio and we discuss the implications of competition in genetically diverse infections for transmission success

Rehabilitation following rotator cuff repair: A multi-centre pilot & feasibility randomised controlled trial (RaCeR)

Objective: To evaluate the feasibility of a multi-centre randomised controlled trial to compare the clinical and cost-effectiveness of early patient-directed rehabilitation versus standard rehabilitation following surgical repair of the rotator cuff of the shoulder. Design: Two-arm, multi-centre pilot and feasibility randomised controlled trial. Setting: Five National Health Service hospitals in England. Participants: Adults (n = 73) with non-traumatic rotator cuff tears scheduled for repair were recruited and randomly allocated remotely prior to surgery. Interventions: Early patient-directed rehabilitation (n = 37); advised to remove their sling as soon as able and move as symptoms allow. Standard rehabilitation (n = 36); sling immobilisation for four weeks. Measures: (1) Randomisation of 20% or more eligible patients. (2) Difference in time out of sling of 40% or more between groups. (3) Follow-up greater than 70%. Results: 73/185 (39%) potentially eligible patients were randomised. Twenty participants were withdrawn, 11 due to not receiving rotator cuff repair. The between-group difference in proportions of participants who exceeded the cut-off of 222.6 hours out of the sling was 50% (80% CI = 29%, 72%), with the early patient-directed rehabilitation group reporting greater time out of sling. 52/73 (71%) and 52/53 (98%) participants were followed-up at 12 weeks when withdrawals were included and excluded respectively. Eighteen full-thickness re-tears were reported (early patient-directed rehabilitation = 7, standard rehabilitation = 11). Five serious adverse events were reported. Conclusion: A main randomised controlled trial is feasible but would require allocation of participants following surgery to counter the issue of withdrawal due to not receiving surgery

The effects of cognitive-linguistic interventions to treat aphasia in the first 90 days post-stroke: A systematic review

Background: Cognitive-linguistic interventions for aphasia are behavioural-based approaches to therapy that aim to treat language impairment skills post-acquired brain injury. The purpose of cognitive-linguistic intervention is to restore and rehabilitate language impairment skills through targeting phonologic, semantic and syntactic systems, which may support goals to improve everyday communication. Aims: The aim of this systematic review was to investigate the effects of cognitive-linguistic interventions on language processing for aphasia in the first 90 days post-stroke. Secondary aims include the investigation of the effects of these interventions on functional communication and quality of life. Methods: A systematic search was conducted across six databases. Twenty-one studies met the predefined eligibility criteria and were included in the review. Studies were rated for methodological quality and data extracted. A narrative synthesis was completed and conducted for all included studies. Four studies were suitable for meta-analysis. Main Contribution: Evidence for the effects of cognitive-linguistic intervention for aphasia in the first 90 days post-stroke is inconclusive. Intervention approaches included constraint-induced intervention, melodic intonation therapy and study specific cognitive-linguistic intervention. Multiple studies investigated the use of computers as a mode of intervention delivery or to increase the frequency of intervention or session duration. Improvement on language outcomes was associated with positive effects on functional communication, regardless of the specific intervention. There were mixed results for quality-of-life outcomes. Conclusions: Further research is required to guide aphasia intervention the first 90 days post stroke, a time critical period for recovery and rehabilitation. Research reports should include adequate description of participant characteristics and consistent use of intervention protocols and outcome measures. Providing a clear description of theoretical underpinnings and detailed information regarding the components of intervention will also facilitate future research synthesis