Development of a millimetrically scaled biodiesel transesterification device that relies on droplet-based co-axial fluidics.

In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here - soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world.

Gait analysis in advanced Parkinson's disease--effect of levodopa and tolcapone.

OBJECTIVE: To determine the therapeutic effect of levodopa/benserazide and tolcapone on gait in patients with advanced Parkinson's disease. METHODS: Instrumental gait analysis was performed in 38 out of 40 patients with wearing-off phenomenon during a randomized, double-blind, placebo-controlled trial of tolcapone. RESULTS: Gait analysis disclosed a significant improvement by levodopa/benserazide in walking speed, stride length and the range of motion of hip, knee and ankle joints. At the end of the study, both the UPDRS motor scores during off-period and the percentage of off time improved significantly using tolcapone. However, gait analysis could not confirm this improvement. With respect to levodopa/benserazide effect, the reduction in rigidity correlated with improved angular excursion of the ankle, whereas the decreased bradykinesia correlated with improved stride length and angular excursion of the hip and knee joints. CONCLUSION: The results of our gait analysis confirmed that in parkinsonian patients with fluctuating motor symptoms levodopa/benserazide, but not tolcapone, produced a substantial improvement.

Detection of oligoclonal bands in patients with neurologic diseases: comparison between agarose gel-, immunofixation- and isoelectric-focusing electrophoresis.

BACKGROUND: The presence of oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) often implies the involvement of the humoral immune response in the disease process. We compared three methods of electrophoresis to determine the frequency and pattern of OCBs in Chinese patients with various neurologic diseases. METHODS: CSF samples and matched serum samples were collected from 122 patients. OCBs were examined in all the CSF samples after agarose gel electrophoresis (AGE) or isoelectric-focusing electrophoresis (IEF); some samples were selected and concentrated for immunofixation electrophoresis (IFE). RESULTS: While 46.7% of the CSF samples showed elevated immunoglobulins using AGE, OCBs were unequivocally identified in 16.4% of samples. In contrast, the detection rate of OCBs using IEF was 54.1%, while that of monoclonal bands was 4.9%. Some OCBs could be detected by IFE, which demonstrated that most of them were IgG-kappa. Using IEF, the sensitivity was 66.7% in multiple sclerosis, 47.8% in myelopathy, 88.9% in chronic inflammatory demyelinating polyradiculoneuropathy, 62.5% in acute inflammatory demyelinating polyradiculoneuropathy, 80.0% in meningoencephalitis and 23.0% in other neurologic diseases. CONCLUSIONS: IEF was the most sensitive method for detecting OCBs. Most patients with type 2 or type 3 patterns of OCBs had multiple sclerosis or meningoencephalitis, although some of these patients may present with a type 4 pattern. Most patients with other diseases had identical patterns of OCBs in both serum and CSF.

Genetic screening for Huntington's disease in Chinese patients with involuntary movements.

The diagnosis of Huntington's disease (HD) can be confirmed by detecting the expanded CAG repeat in the IT15 gene. Besides chorea, patients with HD may present with a variety of bizarre involuntary movements, resulting in confusion in making the diagnosis. Under such conditions, genetic analysis is the final confirmatory test. To determine if any patient with involuntary movements of undetermined etiology might be related to HD, we did genetic analysis on 22 patients and identified three with expanded CAG repeat. We could not obtain family history of HD in these patients due to adoption, early death of parents, or a vague history. All three patients were among the group with generalized chorea, but one had additional marked dystonic posturing. Together with four clinically recognizable HD patients, the relative frequency of HD among the 103 patients with choreiform movements in this hospital is 6.8%.

An add-on study of selegiline to Madopar in the treatment of parkinsonian patients with dose-related fluctuations: comparison between Jumexal and Parkryl.

BACKGROUND: To improve dose-related fluctuations in patients with Parkinson's disease, the efficacy of selegiline, a selective inhibitor of monoamine oxidase B, was determined. METHODS: Twenty parkinsonian patients were selected for a short-term, single-blind, cross-over trial. Each patient received one of the two brands of selegiline, Parkryl (Mei-Shih), 10 mg per day as an adjunct to Madopar. After a 6-week treatment period and a 4-week wash-out period, the treatment was switched to the other brand of selegiline, Jumexal (Labatec), for another 6 weeks. RESULTS: Five patients dropped out of the study because of the development of intolerable dyskinesia, hallucination or agitation. The 15 patients that completed the study made a mild improvement in the total motor scores of the on-period during both treatments of Parkryl (p < 0.01) and of Jumexal (p < 0.05). The recorded daily off-time decreased from 37.8% to 20.7% in the Parkryl group (p < 0.01), and to 21.0% in the Jumexal group (p < 0.01). CONCLUSION: Selegiline, as an adjunct therapy to Madopar, has a moderate effect in prolonging the duration of on-time in parkinsonian patients with dose-related fluctuations. Jumexal seemed to produce no greater effect than Parkryl.

Experience of pergolide in the treatment of Chinese parkinsonian patients with dose-related fluctuations.

BACKGROUND: To improve dose-related fluctuations in patients with Parkinson's disease, the efficacy of pergolide, a long-acting dopamine receptor agonist, was determined. METHODS: Using a stringent diagnostic criterion for Parkinson's disease, 20 patients were selected for a short-term open-label trial, and were divided into three groups based on the accuracy of clinical diagnosis. RESULTS: Nineteen patients completed the study. The mean dosage of pergolide was 2.89 mg per day. The total motor score improved by 34.1% during the "on" period and by 34.8% during the "off" period (p < 0.001). The recorded daily off time decreased from 40.3% to 11.5% (p < 0.001). There was no statistically significant difference in the magnitude of response among different groups of patients; however, patients with shorter duration of illness also received significantly lower dosage of pergolide. Hallucination, worsening of peak-dose dyskinesia, and lowering of blood pressure were major adverse effects. Pergolide could not prevent the occurrence of neuroleptic malignant syndrome in one patient. CONCLUSIONS: Pergolide is very effective for moderate to advanced Parkinson's disease.

Absence of 4,977-bp deletion of blood cell mitochondrial DNA in patients with young-onset Parkinson's disease.

Decreased mitochondrial Complex I activities and a 4,977-bp deletion in mitochondrial DNA (mtDNA) have been reported in patients with Parkinson's disease. Based on the assumption of possible links between this 4,977-bp deletion and the etiology of Parkinson's disease, we analyzed mtDNA of blood cells from 15 patients with young-onset Parkinson's disease after the DNA was amplified by polymerase chain reaction. We could not detect the 4,977-bp mtDNA deletion in any of these patients. This result suggests that Parkinson's disease is not a mitochondrial disease due to the 4,977-bp mtDNA deletion. The 4,977-bp deletion in mtDNA appears to be an age-related phenomenon.