Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network.

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor (ATFBR) with a mesoporous granular activated carbon (GAC) as a support material. The experimental protocol was defined to examine the effect of the maximum organic loading rate (OLR), hydraulic retention time (HRT), the efficiency of the reactor and to report on its steady-state performance. The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m3 x d). The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m3/(m3 x d) of the reactor. With the increase of OLR from 83.7 kg COD/(m3 x d), the COD removal efficiency decreased. Also an artificial neural network (ANN) model using multilayer perceptron (MLP) has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data, the experimental values obtained have been used. The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data. The mean square error (MSE) was found to be only 0.0146.

Seaweeds for the remediation of wastewaters contaminated with zinc(II) ions.

Eleven different species of marine macroalgae were screened at different pH conditions on the basis of zinc(II) biosorption potential. Among the seaweeds, a green alga, Ulva reticulata, exhibited a highest uptake of 36.1 mg/g at pH 5.5 and 100 mg/l initial zinc(II) concentration. Further experiments were conducted to evaluate the zinc(II) biosorption potential of U. reticulata. Sorption isotherm data obtained at different pH (5-6) and temperature (25-35 degrees C) conditions were fitted well with Sips model followed by Freundlich, Redlich-Peterson and Langmuir models. A maximum zinc(II) biosorption capacity of 135.5 mg/g was observed at optimum conditions of 5.5 (pH) and 30 degrees C (temperature), according to the Langmuir model. It was observed from the kinetic data that the zinc(II) biosorption process using U. reticulata follows pseudo-second-order kinetics. Various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees and DeltaS degrees were calculated and they indicated that the present system was a spontaneous and an endothermic process. The influence of the co-ions (Na(+), K(+), Ca(2+) and Mg(2+)) along with zinc(II) present in the wastewater was also studied. Desorption of zinc(II) ions from the zinc(II)-loaded biomass were examined using 0.1 M CaCl(2) at different pH conditions in three sorption-desorption cycles. A fixed-bed column (2 cm i.d. and 35 cm height) was employed to evaluate the continuous biosorption performance of U. reticulata. The column experiments at different bed heights and flow rates revealed that the maximum zinc(II) uptake was obtained at the highest bed height (25 cm) and the lowest flow rate (5 ml/min). Column data were fitted well with Thomas, Yoon-Nelson and modified dose-response models. The column regeneration studies were carried out for three sorption-desorption cycles. A loss of sorption performance was observed during regeneration cycles indicated by a shortened breakthrough time and a decreased zinc(II) uptake.

High-yield fermentation of pentoses into lactic acid.

Lactobacillus species capable of fermenting glucose are generally incapable of utilizing xylose for growth or fermentation. In this study, a novel aspect of a well-known Lactobacillus strain, L. casei subsp. rhamnous (ATCC 10863), was uncovered: it can ferment xylose as efficiently as glucose. This strain is a registered organism, extremely stable on long-term operation. Fermentation by this strain is characterized by an initial lag phase lasting 24-72 h before xylose consumption takes place. The yield (grams/gram) of lactic acid from xylose is in excess of 80% with initial volumetric productivity of 0.38 g/(L.h). Acetic acid is the primary byproduct formed at the level of about 10% of the lactic acid. In addition to xylose, it can ferment all other minor sugars in hemicellulose except arabinose. Subjected to mixed sugar fermentation, this strain consumes glucose first, then mannose, followed by almost simultaneous utilization of xylose and galactose. It shows high tolerance for lactic acid as well as extraneous toxins. It can ferment the mixed sugars present in acid-treated hydrolysate of softwood, giving yields similar to that of pure sugar but at a slower rate.

Simultaneous saccharification and extractive fermentation of lignocellulosic materials into lactic acid in a two-zone fermentor-extractor system.

Simultaneous saccharification and extractive fermentation of lignocellulosic materials into lactic acid was investigated using a two-zone bioreactor. The system is composed of an immobilized cell reactor, a separate column reactor containing the lignocellulosic substrate and a hollow-fiber membrane. It is operated by recirculating the cell free enzyme (cellulase) solution from the immobilized cell reactor to the column reactor through the membrane. The enzyme and microbial reactions thus occur at separate locations, yet simultaneously. This design provides flexibility in reactor operation as it allows easy separation of the solid substrate from the microorganism, in situ removal of the product and, if desired, different temperatures in the two reactor sections. This reactor system was tested using pretreated switchgrass as the substrate. It was operated under a fed-batch mode with continuous removal of lactic acid by solvent extraction. The overall lactic acid yield obtainable from this bioreactor system is 77% of the theoretical.

Poorly differentiated squamous cell carcinomas of the skin can express vimentin.

Thirty cases of poorly differentiated carcinomas of the skin were examined for the expression of vimentin. All cases expressed cytokeratins; in addition, 12 cases were positive for vimentin. These were all non-reactive with antibodies to S100 protein, HMB45 and desmin. The finding of vimentin in poorly differentiated squamous cell carcinomas underscores the need for caution in the use of immunohistochemical stains for tumor typing. Cutaneous squamous cell carcinomas are an addition to the list of epithelial tumors which are known to coexpress vimentin intermediate filaments. Other carcinomas which consistently express vimentin include those of renal, endometrial, thyroid, pulmonary, ovarian, salivary gland, adrenal and more recently, those of breast and prostatic origin.

Kohlmeier-Degos disease: a multisystem vasculopathy with progressive cerebral infarction.

Kohlmeier-Degos disease, or malignant atrophic papulosis, is a rare and clinically distinctive vasculopathy characterised by cutaneous features with frequent gastrointestinal and neurological involvement and, almost invariably, with fatal outcome. The case is reported of a 22-year-old male who died of progressive cerebral infarction nine months from the time of development of pathognomonic skin lesions. Treatments with anti-platelet agents and plasma exchange were ineffectual in altering the progressive course of the disease. At autopsy, there was an extensive small vessel occlusive vasculopathy with similar features in skin, brain and bowel wall. The aetiology of Kohlmeier-Degos disease remains unknown. Diagnosis is on clinico-pathological grounds. Awareness of the disease is important, particularly in the differential diagnosis of cerebrovascular-arteritic-syndromes presenting in young adults.

Malignant dermal cylindromas. Do they exist? A morphological and immunohistochemical study and review of the literature.

Malignant dermal cylindromas are very rare. We present a case of multiple cylindromas of the scalp with metastasis to a cervical lymph node. The morphology of the tumour was unusual in that it contained eccrine spiradenoma-like areas and foci of squamous differentiation with keratin formation. The immunohistochemical phenotype of the eccrine spiradenoma-like areas and the metastatic tumour was similar, but different from the areas of typical cylindroma. Although alleged "malignant" cylindromas have been reported, none have been described to have metastasized, whereas metastatic eccrine spiradenoma is well-documented. We reiterate that overlaps between dermal cylindroma and eccrine spiradenoma are more common than has been documented. In the rare event of metastases, it is the eccrine spiradenomatous component that is metastatic. We contend that there is no evidence that pure dermal cylindromas have metastasized.

Bilateral internuclear ophthalmoplegia--an unusual initial presenting sign of giant cell arteritis.

A 63-year-old man presented six days after the sudden onset of horizontal double vision. His left eye became divergent two days later. On initial examination he had bilateral internuclear ophthalmoplegia with weakness of adduction and abducting nystagmus. Convergence was weak but there were no other neuro-ophthalmic signs. Constitutional signs included confusion and unsteadiness on his feet. A provisional diagnosis of arteritis was made. His ESR was 92 mm/h and a superficial temporal artery biopsy confirmed the diagnosis of giant cell arteritis. After two weeks or oral prednisolone his eye movements returned to normal. There have been no further relapses. This would appear to be a unique presentation of giant cell arteritis. The causes of internuclear ophthalmoplegia are discussed along with a review of the ocular and neuro-ophthalmic signs of giant cell arteritis.

Uterine leiomyosarcoma with myxoid stroma.

Myxoid leiomyosarcomas present a diagnostic problem. They are said to have low mitotic counts and are considered to be exceptions to the general rule that uterine smooth-muscle tumors with a mitotic rate of less than five per ten high-power fields rarely recur. We present two cases of myxoid leiomyosarcoma, both of which show high mitotic counts. In addition, one of the cases presented initially as a typical leiomyosarcoma, but contained abundant myxoid stroma in the metastases. The role of the myxoid stroma in influencing prognosis in leiomyosarcomas is, as yet, uncertain.

Bilateral juvenile granulosa cell tumours associated with skeletal enchondromas.

Asynchronous bilateral granulosa cell tumours of the ovary occurred in a patient with enchondromas. The first tumour, presenting at age 15, was misdiagnosed initially as an androblastoma. The second tumour presented 7 years and 3 pregnancies later. The possible therapeutic and pathogenetic implications of these observations are discussed.

Benign senile pyometra, endometrial cholesterol granulomas and adenosquamous carcinoma.

Endometrial curettage of a 78-year-old patient with benign senile pyometra revealed endometrial cholesterol granulomas. Five years later cytological studies were suspicious of malignancy. Hysterectomy disclosed an endometrial adenosquamous carcinoma associated with cholesterol granulomas. We speculate that endometrial cholesterol granuloma, like endometrial xanthogranuloma, represents a rare morphologic variant of benign senile pyometra. Consequently a strong association with carcinoma is to be expected.

Hydatid cyst: an unusual cause of diplopia.

A 59-year-old man presented with double vision due to vertical displacement of one eye by an infraorbital mass that indented the globe. Some 10 years previously he had had a Caldwell-Luc antrostomy for chronic sinusitis. Following investigation, the antrostomy was revised and an orbital cyst with a histological appearance suggestive of a mucocele was excised via an anterior inferior orbitotomy. The orbital mass recurred with identical symptoms some 18 months later with a second mass confluent with the first, presenting subcutaneously through his zygoma. A further radical antrostomy was performed enabling a diagnosis of a hydatid cyst of the antrum to be made. The unusual features of this rare cause of diplopia are discussed and illustrated. The literature on orbital hydatid cysts is reviewed and recommendations made as regards adequate surgical exposure and not irrigating orbital cysts with noxious agents.

Xanthogranulomatous endometritis associated with endometrial carcinoma.

We studied a case of xanthogranulomatous (XG) endometritis associated with endometrial adenocarcinoma. Isolated XG endometritis is a rare entity that may mimic carcinoma as a consequence of the replacement of the endometrium and the invasion of the myometrium by friable yellowish tissue composed of foamy histiocytes. To our knowledge, it has not previously been described as coexisting with a carcinoma. The XG reaction is characterized by pigment-laden foamy cells. Electron microscopy demonstrated that the foamy cells belong to the macrophage/histiocyte series and are not endometrial stromal cells. Histochemical studies revealed the pigment to be composed of hemosiderin and lipofuscin. The absence of calcispherites or a uniform immunoperoxidase staining reaction for alpha 1-antitrypsin excluded the diagnosis of malacoplakia. We have postulated that XG endometritis has a similar etiopathogenesis to XG pyelonephritis and XG cholecystitis. It is a rare morphologic expression of the clinical syndrome of benign senile pyometrium.

Histopathology of the stapes in otosclerosis.

A histopathological examination was made of 60 stapes obtained during surgery for clinical otosclerosis. The findings, correlated with the clinical history and macroscopic appearances of the stapes, led to the following observations. The histological extent of the focus of otosclerosis agrees well with the macroscopic appearance of the footplate lesion seen under the operating microscope. The earlier the age of onset of hearing loss the greater the probability of active, severe and diffuse otosclerotic involvement of the footplate. Two-thirds of the cases with diffuse and severe footplate otosclerosis had signs of active disease. A late age of onset of clinical otosclerosis tends to be associated with lesions that are limited to the anterior pole of the stapes footplate. Active otosclerosis is rare in these cases. The case for macroscopic increase in extent of the lesion with time could not be established by the data. The evidence supports the view that the severity and extent of otosclerotic disease in the footplate is determined more by age at onset than by duration of symptoms. Healing of the active focus of otosclerosis may not always occur despite a long duration of symptoms. A highly active focus in the stapes footplate can remain active for many years.