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.

Craniospinal giant cell tumors: clinicoradiological analysis in a series of 11 cases.

Primary craniospinal giant cell tumors are rare (5-15% of all giant cell tumors), locally destructive bone lesions which are generally not associated with Paget's disease. Clinical behavior of the craniospinal giant cell tumor (GCT) is unpredictable but often very aggressive and therefore optimal management of the lesions remains controversial. Wide resection of the involved bone is required, preferably with a wide margin of normal tissue, which may be difficult to achieve in the craniospinal region. The authors analysed a series of 11 patients, which included five cases of cranial and six cases of spinal GCTs. Their ages ranged from 12 to 46 years with a male preponderance. In the five cranial cases, all the tumors involved the skull base, three involved the spheno - ethmoidal region and in two cases the petroclival region was involved. Common presenting symptoms were frontotemporal swelling, epistaxis, local pain and neurological deficits attributable to the neurovascular compression. Proptosis, visual loss, nasal mass and cranial nerve involvement were the common findings. In the six patients with spinal lesions (one cervical, four thoracic and one thoracolumbar), local pain, progressive sensory motor deficits and bladder involvement were common presentations. Neuroimaging studies were performed in various combinations for preoperative evaluation and surgical planning. In cranial cases, multidisciplinary approaches were used to perform a near total or a total excision. In the spinal GCTs, only a partial excision was possible. Postoperative radiotherapy was delivered in ten patients. Histopathological studies were diagnostic. All patients were followed up for periods ranging from one to 10 years, with a mean of 2 years and 3 months. No significant increase in the residual tumor or recurrences, as seen on periodic neuroimaging studies, were noted during their follow-up period.

Rathke's cleft cyst presenting as pituitary apoplexy.

Sellar lesions mainly constitute pituitary adenomas, craniopharyngiomas and benign cysts. Rathke's pouch cyst is a developmental sellar and/or suprasellar cystic lesion lined by a single layer of ciliated cuboidal or columnar epithelium, which rarely be comes symptomatic. The authors present an interesting case of intrasellar Rathke's pouch cyst, with a presenting feature of acute pituitary apoplexy. This was a 19 year old healthy male who had developed sudden headache and visual disturbance. Neuro-radiological imaging revealed a mass in the sella. Via transsphenoidal approach a haemorrhagic intrasellar cystic lesion was removed and was confirmed as a haemorrhagic Rathke's cleft cyst by histopathological examination. Interesting clinical presentations and the neuroimaging findings are described and discussed.

Trans-sellar trans-sphenoidal encephaloceles: report of two cases.

Trans-sphenoidal encephaloceles are rare entities. Only about 20 such cases have been reported in the world literature to date. Among these, the trans-sellar variety is rarest (five cases). We present two cases of trans-sellar trans-sphenoidal encephaloceles seen over the last 12 years. The first case was a 5 month old male infant presenting with nasal obstruction and a mass in the mouth. The second case was a 14 year old boy presenting with chronic nasal obstruction since early childhood. In the first case, the mass was coming to the mouth through the split palate. In the second case, the mass could be seen in the posterior half of the nose by rhinoscopy. The computed tomography scans including coronal and sagittal reconstructions had revealed trans-sellar trans-sphenoid encephaloceles in both the patients. The magnetic resonance imaging in the second case showed the cavity and the structures of the floor of the third ventricle forming the main fundal contents. The magnetic resonance angiography revealed dipping of the ectatic anterior cerebral arteries in the neck of the encephalocele sac in this case. Extracranial trans-palatal approach and the repair of encephalocele was done in the first case with the palatal reconstruction at the same sitting. In the second patient, a trans-nasal approach with bilateral maxillotomies was performed to repair the encephalocele, and the skull base defect was repaired by a split rib graft, which was fixed with mini-plate and screws posteriorly at the clivus and anteriorly at the anterior edge of the bony defect. The cleft lip and hypertelorism also were corrected at the same sitting. Our first case had CSF leak on the 10th postoperative day and developed fulminant meningitis, despite appropriate antibiotics, and succumbed. The second patient had a good postoperative recovery and a satisfactory follow up for 2 years.

An unusual posterior mediastinal lipoblastoma with spinal epidural extension presenting as a painful suprascapular swelling: case report and a brief review of the literature.

Lipoblastoma is a rare benign pediatric neoplasm of fetal-embryonal fat with little risk of recurrence following total microsurgical excision, but it may progress to local invasion or infiltration if not treated surgically. No adjuvant therapies are usually necessary once the tumor is excised. It is best diagnosed on histopathological studies following excision. An unusual posterior mediastinal lipoblastoma in a 2-year-old Omani girl with spinal epidural extension clinically manifested as a progressive painful suprascapular swelling is reported. It was initially construed to be a benign lipoma, but progressively increasing pain and mild imbalance whilst walking with a tendency to fall on the right side prompted neurosurgical referral and eventual total excision without any added morbidity. Interesting clinical and neuroimaging (CT & MRI) findings are presented and discussed, with a brief review of the literature.

Congenital intra-extracranial dumbbell schwannoma of temporal fossa unassociated with any major cranial nerve.

Intracranial schwannomas commonly arise from the vestibular nerve and less commonly from other cranial nerves. On rare occasions, they may be intraparenchymatous, intraventricularor intrasellar. However, the occurrence of a congenital solitary intracranial extradural schwannoma unrelated to any cranial nerve in the absence of von Recklinghausan's syndrome is exceptional. The authors report a unique, heretofore unreported case of a congenital temporal extradural schwannoma, unassociated with any known cranial nerve and with a transcranial extension presenting as a temporal fossa mass since birth in a 16-year-old female patient. Total resection of this tumour was uncomplicated. A brief review of the relevant literature is presented.

Symptomatic cranial fibrous dysplasias: clinico-radiological analysis in a series of eight operative cases with follow-up results.

Cranial fibrous dysplasias are rare and comprise less than one percent of all primary bone lesions. These painless progressively expanding destructive bone swellings produce cosmetic deformities (commonest), sino-orbital and auditive complications (less common), peripheral compressive cranial neuropathies (uncommon) and compressive central neurological manifestations (rarest). Until recently some of the primary dysplastic skull base lesions were either treated expectantly or excised incompletely. In a significant percentage of cases, these lesions were considered inaccessible. However, with the development of modern neuro-imaging (CT and MRI) and the applications of current skull base approaches, the more aggressive and radical surgical procedures are being undertaken, with a significant improvement in overall outcome. We present a series of 8 cases of fibrous dysplasia in the age group of 10-33 years with a mean age of 19.75 years. Four cases each had monostotic type and polyostotic type. All patients presented with mild to moderate headaches, and seven cases with some form of cosmetic deformity. In 4 patients there was a unilateral proptosis, while only two had visual deterioration. One patient had anosmia and one hearing impairment. In one case fibrous dysplasia was hemicranial, and in another case the disease was pancranial. Neuro-imaging studies have well delineated the extent of the lesions. In two patients with unilateral fronto-orbital fibrous dysplasia, the removal of dysplastic bone, autoclaving and remodeling and replacement were performed. In two patients of sphenoidal wing fibrous dysplasia a total excision was possible. In the remaining four patients, a partial excision was performed. Overall outcome was good. There was no mortality. One patient had recurrent post-operative extradural haematomas. The authors present the results of an analysis of eight surgically treated cases of symptomatic cranial fibrous dysplasias along with their long-term outcome and the lessons learnt from this series.

Pediatric giant cell granuloma of the temporal bone: a case report and brief review of the literature.

Giant cell granuloma of the skull base is a distinct rare clinicopathologic lesion, which progressively destroys the involved bone. It causes increased intracranial pressure and mass effect on the brain. Histologically it may mimic an aneurysmal bone cyst, giant cell tumour and the brown tumour of hyperparathyroidism. Although cited by some authors, the role of trauma in its aetiology is still considered controversial. Authors present an interesting case of a 12 year old Omani boy who sustained a cricket bat injury to his right temporal region from which he initially recovered but later on progressively developed vertigo, tinnitus, right hearing loss and a mild right facial weakness. Computed tomography (CT scan) and Magnetic resonance imaging (MR scan) revealed a large destructive lesion of the temporal bone. Microsurgical excision was curative. Interesting clinicoradiological findings are presented with a brief review of the literature.

Clinical and hemodynamic study of tilting disc heart valve: Single-center study.

BACKGROUND: The TTK Chitra heart valve has been developed and widely used in India. This study aimed to evaluate its hemodynamics, complications, and event-free survival in comparison with other commonly used prosthetic valves. The role of color Doppler echocardiography in the follow-up of patients with prosthetic valves was also studied. PATIENTS AND METHODS: Two hundred patients underwent 249 valve replacements (122 mitral, 29 aortic, 49 both). Total follow-up was 451 patient-years. RESULTS: There were 18 late deaths (3.98% ± 0.92% per patient-year). One mitral valve replacement patient (0.36% ± 0.36% per patient-year) developed valve thrombosis. Two aortic valve replacement patients (2.74% ± 1.91% per patient-year), 2 double-valve replacement patients (1.95% ± 1.36% per patient-year) and 3 mitral valve replacement patients (1.08% ± 0.62% per patient-year) developed embolic complications. Freedom from all valve related mortality and morbidity at 4 years was 86% ± 4% for mitral valve replacement, 56% ± 10% for double-valve replacement, and 89% ± 6% for aortic valve replacement. The average peak gradient, mean gradient, and average peak velocity for the aortic and mitral positions were found to be comparable to those of other commonly used valves. CONCLUSION: The performance of this valve in terms of hemodynamic complications, mortality, and morbidity is comparable to other valves in common use. Hemodynamic gradients are more reproducible than effective orifice area, hence more beneficial for follow-up.

Ionic liquids as powerful solvent media for improving catalytic performance of silyl borate catalyst to promote Diels-Alder reactions.

Use of the acidic chloroaluminate ionic liquid, including the recycled ones, can improve the catalytic activity of the toluene-coordinated silyl borate in enhancing rates, stereoselectivities, and yields of Diels-Alder reactions.