Physiology of purple sulfur bacteria forming macroscopic aggregates in Great Sippewissett Salt Marsh, Massachusetts

Abstract Purple bacterial aggregates found in tidal pools of Great Sippewissett Salt Marsh (Falmouth, Cape Cod, MA) were investigated in order to elucidate the ecological significance of cell aggregation. Purple sulfur bacteria were the dominant microorganisms in the aggregates which also contained diatoms and a high number of small rod-shaped bacteria. Urea in concentrations of ≥ 1 M caused disintegration of the aggregates while proteolytic enzymes, surfactants or chaotropic agents did not exhibit this effect. This suggests that polysaccharides in the embedding slime matrix stabilize the aggregate structure. In addition cell surface hydrophobicity is involved in aggregate formation. The concentration of dissolved oxygen decreased rapidly below the surface of aggregates while sulfide was not detected. The apparent respiration rate in the aggregates was high when the purple sulfur bacteria contained intracellular sulfur globules. In the presence of DCMU, respiration remained light-inhibited. Light inhibition disappeared in the presence of KCN. These results demonstrated that respiration in the aggregates is due mainly to purple sulfur bacteria. The concentration of bacteriochlorophyll (Bchl) a in the aggregates (0.205 mg Bchl a cm−3) was much higher than in the pool sediments but comparable to concentrations in microbial mats of adjacent sand flats. Purple aggregates may therefore originate in the microbial mats rather than in the pools themselves. Rapid sedimentation and high respiration rates of Chromatiaceae in the aggregates would prevent the inhibition of Bchl synthesis if aggregates were lifted off the sediment and up into the oxic pool water by tidal currents

Absolute estimation of initial concentrations of amplicon in a real-time RT-PCR process

<p>Abstract</p> <p>Background</p> <p>Since real time PCR was first developed, several approaches to estimating the initial quantity of template in an RT-PCR reaction have been tried. While initially only the early thermal cycles corresponding to exponential duplication were used, lately there has been an effort to use all of the cycles in a PCR. The efforts have included both fitting empirical sigmoid curves and more elaborate mechanistic models that explore the chemical reactions taking place during each cycle. The more elaborate mechanistic models require many more parameters than can be fit from a single amplification, while the empirical models provide little insight and are difficult to tailor to specific reactants.</p> <p>Results</p> <p>We directly estimate the initial amount of amplicon using a simplified mechanistic model based on chemical reactions in the annealing step of the PCR. The basic model includes the duplication of DNA with the digestion of Taqman probe and the re-annealing between previously synthesized DNA strands of opposite orientation. By modelling the amount of Taqman probe digested and matching that with the observed fluorescence, the conversion factor between the number of fluorescing dye molecules and observed fluorescent emission can be estimated, along with the absolute initial amount of amplicon and the rate parameter for re-annealing. The model is applied to several PCR reactions with known amounts of amplicon and is shown to work reasonably well. An expanded version of the model allows duplication of amplicon without release of fluorescent dye, by adding 1 more parameter to the model. The additional process is helpful in most cases where the initial primer concentration exceeds the initial probe concentration. Software for applying the algorithm to data may be downloaded at <url>http://www.niehs.nih.gov/research/resources/software/pcranalyzer/</url></p> <p>Conclusion</p> <p>We present proof of the principle that a mechanistically based model can be fit to observations from a single PCR amplification. Initial amounts of amplicon are well estimated without using a standard solution. Using the ratio of the predicted initial amounts of amplicon from 2 PCRs is shown to work well even when the absolute amounts of amplicon are underestimated in the individual PCRs.</p

Optimizing the colour and fabric of targets for the control of the tsetse fly Glossina fuscipes fuscipes

Background: Most cases of human African trypanosomiasis (HAT) start with a bite from one of the subspecies of Glossina fuscipes. Tsetse use a range of olfactory and visual stimuli to locate their hosts and this response can be exploited to lure tsetse to insecticide-treated targets thereby reducing transmission. To provide a rational basis for cost-effective designs of target, we undertook studies to identify the optimal target colour. Methodology/Principal Findings: On the Chamaunga islands of Lake Victoria , Kenya, studies were made of the numbers of G. fuscipes fuscipes attracted to targets consisting of a panel (25 cm square) of various coloured fabrics flanked by a panel (also 25 cm square) of fine black netting. Both panels were covered with an electrocuting grid to catch tsetse as they contacted the target. The reflectances of the 37 different-coloured cloth panels utilised in the study were measured spectrophotometrically. Catch was positively correlated with percentage reflectance at the blue (460 nm) wavelength and negatively correlated with reflectance at UV (360 nm) and green (520 nm) wavelengths. The best target was subjectively blue, with percentage reflectances of 3%, 29%, and 20% at 360 nm, 460 nm and 520 nm respectively. The worst target was also, subjectively, blue, but with high reflectances at UV (35% reflectance at 360 nm) wavelengths as well as blue (36% reflectance at 460 nm); the best low UV-reflecting blue caught 3× more tsetse than the high UV-reflecting blue. Conclusions/Significance: Insecticide-treated targets to control G. f. fuscipes should be blue with low reflectance in both the UV and green bands of the spectrum. Targets that are subjectively blue will perform poorly if they also reflect UV strongly. The selection of fabrics for targets should be guided by spectral analysis of the cloth across both the spectrum visible to humans and the UV region

Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship

Successful treatment of recurrent small bowel adenocarcinoma by cytoreductive surgery and chemotherapy: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Small bowel adenocarcinoma is a rare malignancy associated with a poor prognosis and there is little evidence of effective treatment. Recurrent small bowel adenocarcinoma is an intractable disease for which there is little information available regarding its treatment by palliative therapy. We present a case of recurrent small bowel adenocarcinoma successfully treated by cytoreductive surgery and palliative chemotherapy.</p> <p>Case presentation</p> <p>We report the case of a 72-year-old Japanese female who developed a peritoneal metastasis from recurrent small bowel adenocarcinoma after curative resection and adjuvant chemotherapy with S-1 and polysaccharide K. She underwent cytoreductive surgery followed by chemotherapy with folinic acid/fluorouracil/oxaliplatin and folinic acid/fluorouracil/irinotecan with polysaccharide K. Subsequently, no sign of a recurrence was observed 42 months after the second operation.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first case report of the successful treatment of peritoneal metastasis from small bowel adenocarcinoma by cytoreductive surgery and combination chemotherapy (folinic acid/fluorouracil/oxaliplatin and folinic acid/fluorouracil/irinotecan with polysaccharide K).</p

Physiological and Psychological Effects of Deception on Pacing Strategy and Performance: A Review

The aim of an optimal pacing strategy during exercise is to enhance performance whilst ensuring physiological limits are not surpassed, which has been shown to result in a metabolic reserve at the end of the exercise. There has been debate surrounding the theoretical models that have been proposed to explain how pace is regulated, with more recent research investigating a central control of exercise regulation. Deception has recently emerged as a common, practical approach to manipulate key variables during exercise. There are a number of ways in which deception interventions have been designed, each intending to gain particular insights into pacing behaviour and performance. Deception methodologies can be conceptualised according to a number of dimensions such as deception timing (prior to or during exercise), presentation frequency (blind, discontinuous or continuous) and type of deception (performance, biofeedback or environmental feedback). However, research evidence on the effects of deception has been perplexing and the use of complex designs and varied methodologies makes it difficult to draw any definitive conclusions about how pacing strategy and performance are affected by deception. This review examines existing research in the area of deception and pacing strategies, and provides a critical appraisal of the different methodological approaches used to date. It is hoped that this analysis will inform the direction and methodology of future investigations in this area by addressing the mechanisms through which deception impacts upon performance and by elucidating the potential application of deception techniques in training and competitive settings

Image Texture Characterization Using the Discrete Orthonormal S-Transform

We present a new efficient approach for characterizing image texture based on a recently published discrete, orthonormal space-frequency transform known as the DOST. We develop a frequency-domain implementation of the DOST in two dimensions for the case of dyadic frequency sampling. Then, we describe a rapid and efficient approach to obtain local spatial frequency information for an image and show that this information can be used to characterize the horizontal and vertical frequency patterns in synthetic images. Finally, we demonstrate that DOST components can be combined to obtain a rotationally invariant set of texture features that can accurately classify a series of texture patterns. The DOST provides the computational efficiency and multi-scale information of wavelet transforms, while providing texture features in terms of Fourier frequencies. It outperforms leading wavelet-based texture analysis methods

MRI of the lung (3/3)-current applications and future perspectives

BACKGROUND: MRI of the lung is recommended in a number of clinical indications. Having a non-radiation alternative is particularly attractive in children and young subjects, or pregnant women. METHODS: Provided there is sufficient expertise, magnetic resonance imaging (MRI) may be considered as the preferential modality in specific clinical conditions such as cystic fibrosis and acute pulmonary embolism, since additional functional information on respiratory mechanics and regional lung perfusion is provided. In other cases, such as tumours and pneumonia in children, lung MRI may be considered an alternative or adjunct to other modalities with at least similar diagnostic value. RESULTS: In interstitial lung disease, the clinical utility of MRI remains to be proven, but it could provide additional information that will be beneficial in research, or at some stage in clinical practice. Customised protocols for chest imaging combine fast breath-hold acquisitions from a "buffet" of sequences. Having introduced details of imaging protocols in previous articles, the aim of this manuscript is to discuss the advantages and limitations of lung MRI in current clinical practice. CONCLUSION: New developments and future perspectives such as motion-compensated imaging with self-navigated sequences or fast Fourier decomposition MRI for non-contrast enhanced ventilation- and perfusion-weighted imaging of the lung are discussed. Main Messages • MRI evolves as a third lung imaging modality, combining morphological and functional information. • It may be considered first choice in cystic fibrosis and pulmonary embolism of young and pregnant patients. • In other cases (tumours, pneumonia in children), it is an alternative or adjunct to X-ray and CT. • In interstitial lung disease, it serves for research, but the clinical value remains to be proven. • New users are advised to make themselves familiar with the particular advantages and limitations

Developing a Standard Set of Patient-centred Outcomes for Adult Oral Health - An International, Cross-disciplinary Consensus.

OBJECTIVE: To develop a minimum Adult Oral Health Standard Set (AOHSS) for use in clinical practice, research, advocacy and population health. MATERIALS AND METHODS: An international oral health working group (OHWG) was established, of patient advocates, researchers, clinicians and public health experts to develop an AOHSS. PubMed was searched for oral health clinical and patient-reported measures and case-mix variables related to caries and periodontal disease. The selected patient-reported outcome measures focused on general oral health, and oral health-related quality of life tools. A consensus was reached via Delphi with parallel consultation of subject matter content experts. Finally, comments and input were elicited from oral health stakeholders globally, including patients/consumers. RESULTS: The literature search yielded 1,453 results. After inclusion/exclusion criteria, 959 abstracts generated potential outcomes and case-mix variables. Delphi rounds resulted in a consensus-based selection of 80 individual items capturing 31 outcome and case-mix concepts. Global reviews generated 347 responses from 87 countries, and the patient/consumer validation survey elicited 129 responses. This AOHSS includes 25 items directed towards patients (including demographics, the impact of their oral health on oral function, a record of pain and oral hygiene practices, and financial implications of care) and items for clinicians to complete, including medical history, a record of caries and periodontal disease activity, and types of dental treatment delivered. CONCLUSION: In conclusion, utilising a robust methodology, a standardised core set of oral health outcome measures for adults, with a particular emphasis on caries and periodontal disease, was developed