Outdoor microalgae cultivation in airlift photobioreactor at high irradiance and temperature conditions: effect of batch and fed-batch strategies, photoinhibition, and temperature stress.

The microalgae Scenedesmus abundans cultivated in five identical airlift photobioreactors (PBRs) in batch and fed-batch modes at the outdoor tropical condition. The microalgae strain S. abundans was found to tolerate high temperature (35-45 °C) and high light intensity (770-1690 µmol m- 2 s- 1). The highest biomass productivities were 152.5-162.5 mg L- 1 day- 1 for fed-batch strategy. The biomass productivity was drastically reduced due to photoinhibition effect at a culture temperature of > 45 °C. The lipid compositions showed fatty acids mainly in the form of saturated and monounsaturated fatty acids (> 80%) in all PBRs with Cetane number more than 51. The fed-batch strategies efficiently produced higher biomass and lipid productivities at harsh outdoor conditions. Furthermore, the microalgae also accumulated omega-3 fatty acid (C18:3) up to 14% (w/w) of total fatty acid at given outdoor condition.

Computational fluid dynamics (CFD) analysis of airlift bioreactor: effect of draft tube configurations on hydrodynamics, cell suspension, and shear rate.

The biomass productivity of microalgae cells mainly depends on the hydrodynamics of airlift bioreactor (ABR). Thus, the hydrodynamics of concentric tube ABR was initially studied using two-phase three-dimensional CFD simulations with the Eulerian-Lagrangian approach. The performance of ABR (17 L) was examined for different configurations of the draft tube using various drag models such as Grace, Ishii-Zuber, and Schiller-Naumann. The gas holdups in the riser and the downcomer were well predicted using E-L approach. This work was further extended to study the dispersion of microalgae cells in the ABR using three-phase CFD simulations. In this model (combined E-E and E-L), the solid phase (microalgae cells) was dispersed into the continuous liquid phase (water), while the gas phase (air bubbles) was modeled as a particle transport fluid. The effect of non-drag forces such as virtual mass and lift forces was also considered. Flow regimes were explained on the basis of the relative gas holdup distribution in the riser and the downcomer. The microalgae cells were found in suspension for the superficial gas velocities of 0.02-0.04 m s-1 experiencing an average shear of 23.52-44.56 s-1 which is far below the critical limit of cell damage.

Mixotrophic cultivation of microalgae to enhance the quality of lipid for biodiesel application: effects of scale of cultivation and light spectrum on reduction of α-linolenic acid.

The research on microalgal biodiesel is focused not only on getting the highest lipid productivity but also desired quality of lipid. The experiments were initially conducted on flask scale (1L) using acetate carbon source at different concentrations viz. 0.5, 2, 3 and 4 g L-1. The optimum concentration of acetate was considered for further experiments in two airlift photobioreactors (10 L) equipped separately with red and white LED lights. The Feasibility Index (FI) was derived to analyze the scalability of mixotrophic cultivation based on net carbon fixation in biomass per consumption of total organic carbon. The experimental strategy under mixotrophic mode of cultivation lowered the α-linolenic acid content of lipid by 60-80% as compared to autotrophic cultivation for Scenedesmus abundans species and yielded the highest biomass and lipid productivities, 59 ± 2 and 17 ± 1.8 mg L-1 day-1, respectively. The TOC, nitrate, and phosphate reduction rates were 74.6 ± 3.0, 11.5 ± 1.4, 9.6 ± 2.4 mg L-1 day-1, respectively. The significant change was observed in lipid compositions due to the scale, mode of cultivation, and light spectra. As compared to phototrophic cultivation, biodiesel obtained under mixotrophic cultivation only met standard biodiesel properties. The FI data showed that the mixotrophic cultivation was feasible on moderate concentrations of acetate (2-3 g L-1).

Characterization of spastic paraplegia in a family with a novel PSEN1 mutation.

Spastic paraparesis has been described to occur in 13.7% of PSEN1 mutations and can be the presenting feature in 7.5%. In this paper, we describe a family with a particularly young onset of spastic paraparesis due to a novel mutation in PSEN1 (F388S). Three affected brothers underwent comprehensive imaging protocols, two underwent ophthalmological evaluations and one underwent neuropathological examination after his death at age 29. Age of onset was consistently at age 23 with spastic paraparesis, dysarthria and bradyphrenia. Pseudobulbar affect followed with progressive gait problems leading to loss of ambulation in the late 20s. Cerebrospinal fluid levels of amyloid-ß, tau and phosphorylated tau and florbetaben PET were consistent with Alzheimer's disease. Flortaucipir PET showed an uptake pattern atypical for Alzheimer's disease, with disproportionate signal in posterior brain areas. Diffusion tensor imaging showed decreased mean diffusivity in widespread areas of white matter but particularly in areas underlying the peri-Rolandic cortex and in the corticospinal tracts. These changes were more severe than those found in carriers of another PSEN1 mutation, which can cause spastic paraparesis at a later age (A431E), which were in turn more severe than among persons carrying autosomal dominant Alzheimer's disease mutations not causing spastic paraparesis. Neuropathological examination confirmed the presence of cotton wool plaques previously described in association with spastic parapresis and pallor and microgliosis in the corticospinal tract with severe amyloid-ß pathology in motor cortex but without unequivocal disproportionate neuronal loss or tau pathology. In vitro modelling of the effects of the mutation demonstrated increased production of longer length amyloid-ß peptides relative to shorter that predicted the young age of onset. In this paper, we provide imaging and neuropathological characterization of an extreme form of spastic paraparesis occurring in association with autosomal dominant Alzheimer's disease, demonstrating robust diffusion and pathological abnormalities in white matter. That the amyloid-ß profiles produced predicted the young age of onset suggests an amyloid-driven aetiology though the link between this and the white matter pathology remains undefined.

Current practices and challenges in using microalgae for treatment of nutrient rich wastewater from agro-based industries.

Considerable research activities are underway involving microalgae species in order to treat industrial wastewater to address the waste-to-bioenergy economy. Several studies of wastewater treatment using microalgae have been primarily focused on removal of key nutrients such as nitrogen and phosphorus. Although the use of wastewater would provide nutrients and water for microalgae growth, the whole process is even more complex than the conventional microalgae cultivation on freshwater media. The former one adds several gridlocks to the system. These gridlocks are surplus organic and inorganic nutrients concentration, pH of wastewater, wastewater color, total dissolved solids (TDS), microbial contaminants, the scale of photobioreactor, batch versus continuous system, harvesting of microalgae biomass etc. The present review discusses, analyses, and summarizes key aspects involved in the treatment of wastewaters from distillery, food/snacks product processing, and dairy processing industry using microalgae along with sustainable production of its biomass. This review further evaluates the bottlenecks for individual steps involved in the process such as pretreatment of wastewater for contaminants removal, concentration tolerance/dilutions, harvesting of microalgae biomass, and outdoor scale-up. The review also describes various strategies to optimize algal biomass and lipid productivities for various wastewater and photobioreactor type. Moreover, the review emphasizes the potential of co-cultivation of microorganism such as yeast and bacteria along with microalgae in the treatment of industrial wastewater.

A Case of Anti-glutamic Acid Decarboxylase-65 Antibody Positive Stiff Person Syndrome Presenting Initially as Acute Peripheral Vestibulopathy, Leading to Delayed Diagnosis After Multiple Hospitalizations.

Stiff person syndrome (SPS), with a prevalence of one to two per million, is an extremely rare neurological condition that is characterized by axial muscle stiffness and rigidity along with intermittent painful muscle spasms. It is often associated with psychiatric co-morbidities such as anxiety and depression. The pathophysiology, although poorly understood, is widely believed to be autoimmune in nature due to the association of anti-glutamic acid decarboxylase-65 (anti-GAD 65) antibodies with this condition. There is also a paraneoplastic variant that is more commonly associated with anti-ampiphysin antibodies. It occurs most commonly in patients with breast cancer followed by colon cancer. Most of the practising neurologists encounter just one or two cases of SPS in their entire careers, hence this condition remains underdiagnosed, leading to significant disability and distress to the patient. In this case report we describe a postmenopausal female who presented initially with symptoms of vertigo and dizziness and was hospitalized multiple times before the diagnosis was reached. Through this article, we attempt to increase awareness about this condition among practising physicians so as to increase the likelihood of earlier diagnosis and treatment.

An integrated approach for microalgae cultivation using raw and anaerobic digested wastewaters from food processing industry.

An integrated approach has been proposed to produce microalgal biodiesel using both raw wastewater (RW) and anaerobically digested wastewater (ADW) of food processing industry without addition of extra nutrients or carbon source for cultivation besides obtaining effluent discharge permissible limits of TN, TP, and COD. Three microalgae species cultivated with following different combinations: RW, ADW, RW + ADW, and glucose + ADW. Results indicated that the addition of RW as a carbon source in ADW significantly enhanced BP, LP, and TN removal as compared to the ADW alone. The runs with RW + ADW removed COD, TN, and TP by 89%, 84%, and 70%, respectively. Sc. obliquus showed highest biomass and lipid productivities (211 and 27.5 mg L-1 d-1) for RW + ADW. The addition of RW or glucose in ADW significantly lowered PUFA contents to 5-15% CDW (as against 35-50% with ADW) for Chl. sorokiniana and Sc. obliquus.

Subgaleal migration of a ventriculoperitoneal shunt.

Blockage of a ventriculoperitoneal (VP) shunt is very common. Here, we describe an unusual case of shunt blockage in an infant. He was shunted for hydrocephalus associated with a Dandy-Walker malformation diagnosed at birth. At surgery, the entire VP shunt was found to have migrated into the subgaleal space, which clinically presented as shunt obstruction. We suggest techniques to avoid this rare, but preventable, complication of shunt surgery.

Intracranial migration of Foley catheter--an unusual complication.

Profuse nasal bleeding in cases of severe head injury is mostly associated with facial and skull base fractures and various methods have been tried to control such bleeding. Anterior nasal packing, producing a tamponade effect with a Foley catheter and other inflatable balloon devices are time proven methods. We describe a case of severe head injury with such fractures where a Foley catheter tamponade was attempted to control the severe nasal bleeding and the CT brain scan revealed inadvertent malposition of the catheter into the cranial cavity. This rare entity is described to highlight the potential danger associated with a proven method of controlling severe nasal bleeding and suggestions are outlined as to how to avoid such a mishap, along with a brief review of the literature.