Lead acid battery storage model for hybrid energy systems

This paper describes a new battery model developed for use in time series performance models of hybrid energy systems. The model is intended to overcome some of the difficulties associated with currently used methods. It is based on the approach of chemical kinetics. This model, which can be used for charging and discharging, is specifically concerned with the apparent change in capacity as a function of charge and discharge rates. It assumes that the charge can be stored in two ways, either as immediately available or as chemically bound. As described in this paper, it requires the determination of as few as three constants. Examples of the deviation of the battery model constants and comparisons of the new model with those used previously are given. Based on the success of the new model, it has been incorporated into the latest versions of the University of Massachusetts's wind/diesel simulation codes.     

Hyperinsulinaemia, dyslipaemia and cardiovascular risk in girls with a history of premature pubarche

Girls with a history of premature pubarche, i.e. appearance of pubic hair before 8 years of age, show hyperinsulinism in response to an oral glucose tolerance test. As hyperinsulinaemia has a major role in dyslipaemia, and is considered an independent risk factor for cardiovascular disease, we assessed the patterns of plasma insulin concentration after a standard oral glucose tolerance test as well as fasting serum lipid, lipoprotein, and sex hormone-binding globulin concentrations in girls (n = 81) with premature pubarche compared with girls (n = 55) matched with them for stage and bone age to ascertain their metabolic states to identify those potentially at risk for the development of premature cardiovascular disease. Mean serum insulin concentrations were higher in patients at all pubertal stages, and associated with elevated serum triglyceride, very low density cholesterol and very low density triglyceride concentrations (p value range 0.04 to < 0.0001) but reduced sex hormone-binding globulin. Premature pubarche patients also displayed higher low density to high density lipoprotein cholesterol ratios compared with control subjects (p = 0.004 to 0.008). In conclusion, hyperinsulinaemia, decreased sex hormone-binding globulin concentrations and an unfavourable lipid pattern are common features in premature pubarche girls supporting the contention that atherogenic abnormalities composing the metabolic syndrome could start in childhood. To determine the clinical sequelae of such clustering of metabolic deviations, girls who were identified need to be followed up for the potential development of premature cardiovascular disease.     

Evacuation defecography and defecoflometry in diagnosis of chronic constipation. A prospective comparative study of 49 patients

Horizontal-canal paroxysmal positional vertigo (HC-PPV) is a vestibular syndrome due to canalolithiasis of the horizontal canal. The more common posterior-canal paroxysmal positional vertigo has a well defined and effective therapy, while there have been few reports on physical therapy for HC-PPV, and these have been tried in relatively few patients. We report the results of two different types of treatment of HC-PPV in 92 patients. A group of 21 untreated patients acted as a control group. One method, known as forced prolonged position (FPP), proposes liberating the affected canal by gravitation, and involves having the patient lie on the healthy side for many hours. The other method (the barbecue rotation) is a liberatory manoeuvre which proposes to expel the otoconia from the canal by rotating the patient 270 degrees around the longitudinal axis of the body in rapid steps of 90 degrees. FPP was successful in more than 70% of our patients; the barbecue rotation had slightly less successful but more immediate results. Both methods enable otoconial debris to migrate into the posterior canal. We suggest treating all patients with the two methods in succession.     

Chronic back pain

Low-back pain is a very common disease in Switzerland as elsewhere, with a prevalence of 65%. The pain is usually due to degeneration of the motion segment, but subsides spontaneously in some 95% of cases irrespective of the treatment. Only 5% of patients still have pain after one year; but account for over 80% of the costs due to low-back pain. Some patients can be helped by surgical fusion; however; preoperative identification of the pain source is mandatory. Since there is no consistent correlation between pain and the degree of degeneration of motion segments as seen on plain radiographs, functional radiographs, CT scan or MRI, other diagnostic methods such as facet blocks, discography and external diagnostic fixation must be used. After careful patient selection a fusion operation may be considered. Good results after fusion operations are reported in 60-80% of patients. The operative techniques are described.     

Neonatal sciatic palsy: etiology and outcome of 21 cases

INTRODUCTION: Sciatic nerve paralysis is a rare entity in the newborn. Few reference in specialized tests indicate that in the majority of cases the sciatic palsy has been observed after misplaced injections into the buttocks. The prognosis is variable and appears to be better after umbilical vessel catheterization for injection of medications than after misplaced muscular injections. In case of recovery it takes place within 3 to 12 months. OBJECTIVE: The objective of the present study is to know the evolution of neonatal sciatic palsy and to determine their injury noxe in regard to perinatal factors, and their relationship with long-time outcome, and to look for prognostic clues of clinical utility. MATERIAL AND METHODS: We evaluated perinatal factors of newborn children with sciatic nerve paralysis, followed for more than 18 months of clinical evolution, in a neuropediatric centre. RESULTS: Twenty one newborn with such criteria were evaluated. Gestational age was within 32 and 42 weeks (median 38.2). The birth weight was between 2,100 and 4,100 g (median 2,973). The majority of cases obtained total recovery (16 of 21). The time of recovery was 4 to 14 months (median 8.8). Free ambulation was obtained by all cases (at 10 to 24 months). No apparent cause was observed in the majority of cases. Cesarean delivery was more frequent specially in cases with permanent consequences. CONCLUSION: Long-time prognostic of neonatal sciatic palsy is generally good. In our series all the cases with consequences were associated to cesarean delivery. The duration of cesarean intervention and the anesthesic hypotony of the newborn could be implicated in the sciatic nerve injury of poor outcome.     

Multicellular and aggregative behaviour of Salmonella typhimurium strains is controlled by mutations in the agfD promoter

To investigate the biochemical requirements for in vivo L-DOPA production by cells genetically modified ex vivo in a rat model of Parkinson's disease (PD), rat syngeneic 9L gliosarcoma and primary Fischer dermal fibroblasts (FDFs) were transduced with retroviral vectors encoding the human tyrosine hydroxylase 2 (hTH2) and human GTP cyclohydrolase I (hGTPCHI) cDNAs. As GTPCHI is a rate-limiting enzyme in the pathway for synthesis of the essential TH cofactor, tetrahydrobiopterin (BH4), only hTH2 and GTPCHI cotransduced cultured cells produced L-DOPA in the absence of added BH4. As striatal BH4 levels in 6-hydroxydopamine (6-OHDA)-lesioned rats are minimal, the effects of cotransduction with hTH2 and hGTPCHI on L-DOPA synthesis by striatal grafts of either 9L cells or FDFs in unilateral 6-OHDA-lesioned rats were tested. Microdialysis experiments showed that those subjects that received cells cotransduced with hTH2 and hGTPCHI produced significantly higher levels of L-DOPA than animals that received either hTH2 or untransduced cells. However, animals that received transduced FDF grafts showed a progressive loss of transgene expression until expression was undetectable 5 weeks after engraftment. In FDF-engrafted animals, no differential effect of hTH2 vs hTH2 + hGTPCHI transgene expression on apomorphine-induced rotation was observed. The differences in L-DOPA production found with cells transduced with hTH2 alone and those cotransduced with hTH2 and hGTPCHI show that BH4 is critical to the restoration of the capacity for L-DOPA production and that GTPCHI expression is an effective means of supplying BH4 in this rat model of PD.     

Isomorphous replacement of cystine with selenocystine in endothelin: oxidative refolding, biological and conformational properties of [Sec3,Sec11,Nle7]-endothelin-1

Air re-oxidation of fully reduced human endothelin-1 under optimized conditions yields the natural isomer with parallel disulfide bridges and the non-natural isomer with crossed disulfide bridges at a ratio of 3:1. In view of the recently determined highly reducing redox potential of selenocysteine (-381 mV) in peptides, the half-cystine residues Cys3 and Cys11 of the natural isomer of endothelin-1 were replaced by selenocysteine. Taking advantage of the high stability of the diselenide group toward reducing agents for disulfides a regioselective disulfide bridging of the second cysteine pair allowed for straightforward preparation of the [Sec3,Sec11, Nle7]-endothelin-1. NMR structural analysis showed conformational preferences of this endothelin analog that were identical to those of the natural hormone. Similarly, the bioactivity data confirmed that replacement of cysteine residues with selenocysteine was without detectable effect on receptor recognition and signal transduction. Both findings strongly support that the exchange of sulfur against selenium produces a fully isomorphous molecule as recently observed for similar exchanges at the level of methionine residues in proteins. Moreover, oxidative refolding of the fully reduced [Sec3,Sec11,Nle7]-endothelin-1 fulfilled the expectation that the redox potential of the selenocysteines would dictate quantitative formation of the natural isomer. These results suggest that the selenocysteine approach, besides offering an interesting chemical tool for induction of correct oxidative folding of multiple cysteine-containing peptides, should even allow for the preparation of non-natural isomers and thus for studying conformational preferences of folding intermediates in peptides and proteins.     

Prevalence of osteoporosis in the Czech Republic

BACKGROUND: The objective of this study was to evaluate the prevalence of osteoporosis and osteopenia in Czech women and men aged 50 to 75 years. METHODS AND RESULTS: Bone mineral density was assessed in an age-stratified random sample of 713 women and 429 men from two cities (Prague and Litom?rice) in the lumbar spine, proximal femur and total body by dual X-ray absorptiometry and in the distal forearm by single X-ray absorptiometry. The proportion of women and men in each age group with bone density below specified levels at any of these skeletal sites was projected to the population structure of the Czech Republic. With advancing age, in women at 55 years and in men at 65 years of age the population with normal bone mineral density becomes smaller, and a greater proportion has osteopenia or osteoporosis. Overall, an estimated 428,000 women and 195,000 men over age 50 have osteoporosis and another 680,000 women and 435,000 men have osteopenia. CONCLUSIONS: The results of this first population-based cross sectional study in the Czech Republic document a high prevalence of osteoporosis and osteopenia which is comparable with that published for the Netherlands and the United States. The results offer a basis for economical considerations in diagnosis, treatment and consequences of osteoporosis.