A two-plane tubular photobioreactor for outdoor culture of Spirulina

A photobioreactor in the form of a 245-m-long loop made of plexiglass tubes having an inner diameter of 2.6 cm was designed and constructed for outdoor culture of Spirulina. The loop was arranged in two planes, with 15 8-m-long tubes in each plane. In the upper plane, the tubes were placed in the vacant space between the ones of the lower plane. The culture recycle was performed either with two airlifts, one per plane, or with two peristaltic pumps. The power required for water recycle in the tubular photobioreactor, with a Reynolds number of 4000, was 3.93 x 10(-2) W m(-2). The photobioreactor contained 145 L of culture and covered an overall area of 7.8 m(2). The photobioreactor operation was computer controlled. Viscosity measurements performed on Spirulina cultures having different biomass concentrations showed non-Newtonian behavior displaying decreasing viscosity with an increasing shear rate. The performance of the two-plane photobioreactor was tested under the climatic conditions of central Italy (latitude 43.8 degrees N, longitude 11.3 degrees E). A biomass concentration of 3.5 g L(-1) was found to be adequate for outdoor culture of Spirulina. With a biomass concentration of 6.3 g L(-1), the biomass output rate significantly decreased. The net biomass output rate reached a mean value of 27.8 g m(-2) d(-1) in July; this corresponded to a net photosynthetic efficiency of 6.6% (based on visible irradiance). (c) 1993 John Wiley & Sons, Inc.     

The xanthophyll cycle in green algae (chlorophyta): its role in the photosynthetic apparatus

Light-dependent conversion of violaxanthin to zeaxanthin, the so-called xanthophyll cycle, was shown to serve as a major, short-term light acclimation mechanism in higher plants. The role of xanthophylls in thermal dissipation of surplus excitation energy was deduced from the linear relationship between zeaxanthin formation and the magnitude of non-photochemical quenching. Unlike in higher plants, the role of the xanthophyll cycle in green algae (Chlorophyta) is ambiguous, since its contribution to energy dissipation can significantly vary among species. Here, we have studied the role of the xanthophyll cycle in the adaptation of several species of green algae (Chlorella, Scenedesmus, Haematococcus, Chlorococcum, Spongiochloris) to high irradiance. The xanthophyll cycle has been found functional in all tested organisms; however its contribution to non-photochemical quenching is not as significant as in higher plants. This conclusion is supported by three facts: (i) in green algae the content of zeaxanthin normalized per chlorophyll was significantly lower than that reported from higher plants, (ii) antheraxanthin + zeaxanthin content displayed different diel kinetics from NPQ and (iii) in green algae there was no such linear relationship between NPQ and Ax + Zx, as found in higher plants. We assume that microalgae rely on other dissipation mechanism(s), which operate along with xanthophyll cycle-dependent quenching.     

Advances in the biotechnology of hydrogen production with the microalga Chlamydomonas reinhardtii

Biological hydrogen production is being evaluated for use as a fuel, since it is a promising substitute for carbonaceous fuels owing to its high conversion efficiency and high specific energy content. The basic advantages of biological hydrogen production over other “green” energy sources are that it does not compete for agricultural land use, and it does not pollute, as water is the only by-product of the combustion. These characteristics make hydrogen a suitable fuel for the future. Among several biotechnological approaches, photobiological hydrogen production carried out by green microalgae has been intensively investigated in recent years. A select group of photosynthetic organisms has evolved the ability to harness light energy to drive hydrogen gas production from water. Of these, the microalga Chlamydomonas reinhardtii is considered one of the most promising eukaryotic H₂ producers. In this model microorganism, light energy, H₂O and H₂ are linked by two excellent catalysts, the photosystem 2 (PSII) and the [FeFe]-hydrogenase, in a pathway usually referred to as direct biophotolysis. This review summarizes the main advances made over the past decade as an outcome of the discovery of the sulfur-deprivation process. Both the scientific and technical barriers that need to be overcome before H₂ photoproduction can be scaled up to an industrial level are examined. Actual and theoretical limits of the efficiency of the process are also discussed. Particular emphasis is placed on algal biohydrogen production outdoors, and guidelines for an optimal photobioreactor design are suggested.     

Regenerative potential of human muscle stem cells in chronic inflammation

Introduction

Chronic inflammation is a profound systemic modification of the cellular microenvironment which could affect survival, repair and maintenance of muscle stem cells. The aim of this study was to define the role of chronic inflammation on the regenerative potential of satellite cells in human muscle.

Methods

As a model for chronic inflammation, 11 patients suffering from rheumatoid arthritis (RA) were included together with 16 patients with osteoarthritis (OA) as controls. The mean age of both groups was 64 years, with more females in the RA group compared to the OA group. During elective knee replacement surgery, a muscle biopsy was taken from the distal musculus vastus medialis. Cell populations from four RA and eight OA patients were used for extensive phenotyping because these cell populations showed no spontaneous differentiation and myogenic purity greater than 75% after explantation.

Results

After mononuclear cell explantation, myogenic purity, viability, proliferation index, number of colonies, myogenic colonies, growth speed, maximum number of population doublings and fusion index were not different between RA and OA patients. Furthermore, the expression of proteins involved in replicative and stress-induced premature senescence and apoptosis, including p16, p21, p53, hTERT and cleaved caspase-3, was not different between RA and OA patients. Mean telomere length was shorter in the RA group compared to the OA group.

Conclusions

In the present study we found evidence that chronic inflammation in RA does not affect the in vitro regenerative potential of human satellite cells. Identification of mechanisms influencing muscle regeneration by modulation of its microenvironment may, therefore, be more appropriate.     

Preliminary investigation on the production of fuels and bio-char from Chlamydomonas reinhardtii biomass residue after bio-hydrogen production

The aim of this work was to investigate the potential conversion of Chlamydomonas reinhardtii biomass harvested after hydrogen production. The spent algal biomass was converted into nitrogen-rich bio-char, biodiesel and pyrolysis oil (bio-oil). The yield of lipids (algal oil), obtained by solvent extraction, was 15 ± 2% w/w_dry-biomass. This oil was converted into biodiesel with a 8.7 ± 1% w/w_dry-biomass yield. The extraction residue was pyrolysed in a fixed bed reactor at 350 °C obtaining bio-char as the principal fraction (44 ± 1% w/w_dry-biomass) and 28 ± 2% w/w_dry-biomass of bio-oil. Pyrolysis fractions were characterized by elemental analysis, while the chemical composition of bio-oil was fully characterized by GC-MS, using various derivatization techniques. Energy outputs resulting from this approach were distributed in hydrogen (40%), biodiesel (12%) and pyrolysis fractions (48%), whereas bio-char was the largest fraction in terms of mass.     

Outdoor photoacclimation of two Chlorella strains characterized by normal and reduced light-harvesting antennas: photosynthetic activity and chlorophyll-protein organization

Journal of Applied Phycology - Photoacclimation of two Chlorella cultures – strain g-120 characterised by a reduced size of light-harvesting antenna complex (LHC) and strain R-117 with full...     

Ultrasound enhanced prehospital thrombolysis using microbubbles infusion in patients with acute ST elevation myocardial infarction: Rationale and design of the Sonolysis study

Background

The CONSORT Statement provides recommendations for reporting randomized controlled trials. We assessed the extent to which leading medical journals that publish reports of randomized trials incorporate the CONSORT recommendations into their journal and editorial processes.

Methods

This article reports on two observational studies. Study 1: We examined the online version of 'Instructions to Authors' for 165 high impact factor medical journals and extracted all text mentioning the CONSORT Statement or CONSORT extension papers. Any mention of the International Committee of Medical Journal Editors (ICMJE) or clinical trial registration were also sought and extracted. Study 2: We surveyed the editor-in-chief, or editorial office, for each of the 165 journals about their journal's endorsement of CONSORT recommendations and its incorporation into their editorial and peer-review processes.

Results

Study 1: Thirty-eight percent (62/165) of journals mentioned the CONSORT Statement in their online 'Instructions to Authors'; of these 37% (23/62) stated this was a requirement, 63% (39/62) were less clear in their recommendations. Very few journals mentioned the CONSORT extension papers. Journals that referred to CONSORT were more likely to refer to ICMJE guidelines (RR 2.16; 95% CI 1.51 to 3.08) and clinical trial registration (RR 3.67; 95% CI 2.36 to 5.71) than those journals which did not. Study 2: Thirty-nine percent (64/165) of journals responded to the on-line survey, the majority were journal editors. Eighty-eight percent (50/57) of journals recommended authors comply with the CONSORT Statement; 62% (35/56) said they would require this. Forty-one percent (22/53) reported incorporating CONSORT into their peer-review process and 47% (25/53) into their editorial process. Eighty-one percent (47/58) reported including CONSORT in their 'Instructions to Authors' although there was some inconsistency when cross checking information on the journal's website. Sixty-nine percent (31/45) of journals recommended authors comply with the CONSORT extension for cluster trials, 60% (27/45) for harms and 42% (19/45) for non-inferiority and equivalence trials. Few journals mentioned these extensions in their 'Instructions to Authors'.

Conclusion

Journals should be more explicit in their recommendations and expectations of authors regarding the CONSORT Statement and related CONSORT extensions papers.     

The Dynamics, Prevalence and Impact of Nematode Infections in Organically Raised Sheep in Sweden

A three-year survey (1997–99) was carried out on organically reared sheep flocks throughout Sweden. The aim was to determine the prevalence and intensity of nematode infections and to establish relationships between sheep management practices and parasite infections. Faecal samples from ewes and lambs were collected from 152 organic flocks around lambing-time and during the grazing-period for analysis. Results were compared with the different management practices that farmers use to prevent parasitism in their flocks. A high proportion of the flocks was infected with nematodes. The most prevalent species were Haemonchus contortus, Teladorsagia circumeincta, Trichostrongylus axei, T. colubriformis and Chabertia ovina and infections progressively increased during summer in lambs grazing on permanent pastures. Severity of parasitic infection in lambs was highly dependent on egg output from the ewes. H. contortus was found in 37% of the flocks, even at latitudes approximating the Polar Circle. Nematodirus battus was recorded for the first time in Sweden during the course of this study. Lambs turned out onto permanent pasture showed higher nematode faecal egg counts (epg) than lambs that had grazed on pastures, which had not carried sheep the previous year. This beneficial effect of lambs grazing non-infected pastures persisted if the ewes were treated with an anthelmintic before turn-out and if the lambs were kept on pastures of low infectivity after weaning. In lambs, the prevalence and the magnitude of their egg counts were higher during autumn in flocks where lambs were slaughtered after 8 months of age, compared with flocks where all lambs were slaughtered before this age. These results will be used in providing advice to farmers of ways to modify their flock management in order to minimise the use of anthelmintics, but at the same time efficiently produce prime lambs.     

The potential for using red claw crayfish and hybrid African catfish as biological control agents for Schistosoma host snails

The potential of red claw crayfish and hybrid African catfish (Clarias gariepinus and Clarias ngamensis) as predators for Schistosoma host snails was evaluated in 2014 by monitoring the consumption of snails by crayfish and catfish in experimental tanks over time under laboratory conditions. After 15 days, both crayfish and catfish had significantly reduced the populations of Bulinus globosus. Crayfish consumed 6.9 snails d^?1, whereas catfish consumed 5.9 snails d^?1. However, when supplied with an alternative prey, Melanoides tuberculata (100 individuals per tank), crayfish clearly preferred M. tuberculata (100% consumed over seven days) to B. globosus (100 individuals per tank) (54% consumed over the same period). Catfish, conversely, did not have a clear preference for either prey species, consuming 77% and 88% of M. tuberculata and B. globosus, respectively. It was also observed that young catfish were more efficient predators than older ones, because of ontogenetic shifts in their diet with age. Hybrid catfish retain the molluscivorous characteristics of their parent stock and red claw crayfish also preys on Schistosoma host snails. However, the effectiveness of both predators is affected by the presence of an alternative prey. Therefore, under suitable conditions, these species can be considered for biological control of schistosomiasis transmission.     

Definition of common carotid wall thickness affects risk classification in relation to degree of internal carotid artery stenosis: the Plaque At RISK (PARISK) study

Background

Mean or maximal intima-media thickness (IMT) is commonly used as surrogate endpoint in intervention studies. However, the effect of normalization by surrounding or median IMT or by diameter is unknown. In addition, it is unclear whether IMT inhomogeneity is a useful predictor beyond common wall parameters like maximal wall thickness, either absolute or normalized to IMT or lumen size. We investigated the interrelationship of common carotid artery (CCA) thickness parameters and their association with the ipsilateral internal carotid artery (ICA) stenosis degree.

Methods

CCA thickness parameters were extracted by edge detection applied to ultrasound B-mode recordings of 240 patients. Degree of ICA stenosis was determined from CT angiography.

Results

Normalization of maximal CCA wall thickness to median IMT leads to large variations. Higher CCA thickness parameter values are associated with a higher degree of ipsilateral ICA stenosis (p?<?0.001), though IMT inhomogeneity does not provide extra information. When the ratio of wall thickness and diameter instead of absolute maximal wall thickness is used as risk marker for having moderate ipsilateral ICA stenosis (>50%), 55 arteries (15%) are reclassified to another risk category.

Conclusions

It is more reasonable to normalize maximal wall thickness to end-diastolic diameter rather than to IMT, affecting risk classification and suggesting modification of the Mannheim criteria.

Trial registration

Clinical trials.gov NCT01208025.