bluuebunny/crossref_metadata_2025 huggingface dataset:
Ex vivo human placental transfer of the peptides pramlintide and exenatide (synthetic exendin-4)
Authors: Hiles Richard A , Bawdon Roger E , Petrella Ezio M
Published: February 2004

Two peptides, pramlintide (37 amino acids), an analog of human amylin, and exenatide, synthetic exendin-4 (39 amino acids), are both in late-stage clinical development as potential new treatments for people with diabetes. Both are potential long-term treatments, and there is the likelihood that some women will become pregnant while using one of these peptide therapies. Therefore, it was important to evaluate the potential for each peptide to cross the placental barrier and thereby result in exposure to the fetus. This was examined using ex vivo perfusions of human placentas. The fetal and maternal side of a cotyledon were cannulated and perfused first with buffer, and then with radioactive antipyrine in order to establish the integrity of the system and the perfusion constants. Either pramlintide or exenatide was then added to each acceptable cotyledon perfusate on the maternal side. Each peptide was evaluated at an initial concentration near the therapeutic plasma concentration and at approximately 10-50 times that concentration in each of the three cotyledons. Maternal and fetal perfusate samples were assayed for peptide concentrations using an immunoassay. The ratio of fetal-to-maternal peptide concentrations during equilibrium perfusion were extremely low (pramlintide ≤ 0.006, exenatide 5 ≤ 0.017). These data demonstrate negligible passage of either peptide across the placental barrier. It is, therefore, likely that maternal use of either peptide during gestation will result in negligible exposure to the fetus.
Species variation in pesticide-induced blood-brain barrier dysfunction
Authors: Sinha Chaitali , Shukla Girja S
Published: February 2004

Neurological disorders following acute or chronic exposure to pesticides have been reported in a number of human cases. However, the mechanism(s) by which pesticides produce central nervous system dysfunction is not clear. The objective of the present study was to examine the functional status of blood-brain barrier (BBB) in rats and mice exposed to selected pesticides of different chemical groups. Adult male albino rats and mice were exposed (1/10 of LD50) daily to dichlorvos (organophosphate), lindane (organochlorine) and carbofuran (carbamate) through oral intubation for 3 days. The status of BBB was evaluated by determining brain sodium fluorescein dye uptake and brain uptake index (BUI) in relation to serum dye level. The brain dye uptake and BUI in pesticide-exposed rats did not differ significantly in comparison to that of controls. However, brain dye uptake and BUI were increased significantly in mice exposed to dichlorvos (85%, 40%), lindane (79%, 26%) and carbofuran (129%, 61%). The results of this study show that mouse BBB system is more sensitive to pesticide-induced breach as compared to that of rat. These variations may have a role in determining the outcome of pesticide neurotoxicity in different species.
Hepatocurative and antioxidant profile of HP-1, a polyherbal phytomedicine
Authors: Tasaduq S A , Singh K , Sethi S , Sharma S C , Bedi K L , Singh J , Jaggi B S , Johri R K
Published: February 2004

HP-1 a herbal formulation comprising of Phyllanthus niruri and extracts of Terminalia belerica, Terminalia chebula, Phyllanthus emblica and Tinospora cordifoliahas been evaluated for hepatoprotective activity against carbon tetrachloride (CCl4) induced toxicity. Results show that HP-1 reversed the leakage of lactate dehydrogenase (LDH) and glutamate pyruvate transaminase (GPT) and prevented the depletion of glutathione (GSH) levels in a primary monolayer culture of rat hepatocytes (in vitro). HP-1 attenuated the serum toxicity as manifested in elevated levels of transaminases (glutamate oxaloacetate transaminase (GOT), and GPT) The anti-oxidative enzymes in liver (catalase and superoxide dismutase (SOD)) were restored to normal values after the oral administration of HP-1. HP-1 suppressed the formation of the superoxide anion radical and reduced CCl4 mediated lipid peroxidation (LPO). Silymarin and antioxidants (ascorbic acid,β-carotene and tocopherol) were used for comparison. The present study showed that HP-1 is a potential hepatoprotective formulation with an additional attribute of being anti-peroxidative.
An in vitro study of biological safety of condoms and their additives
Authors: Motsoane N A , Bester M J , Pretorius E , Becker P J
Published: February 2004

The use of condoms to prevent sexually transmitted diseases, especially HIV, is widely encouraged. Condoms contain latex, nonspermicidal lubricants (such as dimethylsiliconium) and other nonspecified compounds, such as colorants and flavorings. Latex causes allergy reaction in susceptible individuals but little is known regarding the cytotoxic effects of other additives. The objective of this study was to develop a sensitive in vitrosystem to determine the toxic effects of condom material. The modified L929 FDA method and a more specific cell type, such as the cervical epithelial tumor cell line HeLa, was used. Lubricated (LC), lubricated and flavored (LFC), and lubricated, flavored and colored condoms (LFCC) were evaluated. Washings containing condom surface material were prepared by washing condom fragments in medium for different time intervals. Changes in cell number, viability and lysosome integrity in the L929 and HeLa cell lines was determined using the Crystal Violet, MTT and Neutral Red assays, respectively. The condom type affected cell viability and lysosome integrity, with LC inducing an increase in cell viability and LFC a decrease in lysosome integrity. The HeLa cell line in combination with the MTT and NR assay was the most sensitive in vitro system to determine the toxic effects of condom material.
Protective effect of curcumin against lead neurotoxicity in rat
Authors: Shukla Pradeep K , Khanna Vinay K , Khan Mohd Y , Srimal Rikhab C
Published: February 2004

Curcumin (diferuloylmethane), an active ingredient of turmeric, is known to have multiple activities, including an antioxidant property, and has been suggested to be of use in treatment of several diseases. The present study has been undertaken to investigate the protective effect of curcumin against lead-induced neurotoxicity in rats. Exposure of rats to lead (50 mg/kg po) for 45 days caused an increase in lipid peroxidation (LPO) and a decrease in reduced glutathione (GSH) levels in cerebellum, corpus striatum, hippocampus and frontal cortex as compared with controls. Lead levels were significantly increased in these rats. Activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) decreased in all the brain regions following lead exposure. Interestingly, cotreatment with curcumin (100 mg/kg po) and lead (50 mg/kg po) for 45 days caused a significant decrease in LPO with concomitant decrease in lead levels in all the brain regions as compared with those treated with lead alone. A significant increase in reduced glutathione (GSH) levels, SOD and CAT activities was also observed in all the four brain regions in rats simultaneously treated with curcumin and lead. The results suggest that curcumin may prevent lead-induced neurotoxicity.
Nitric Oxide Donor Increases Osteoprotegerin Production and Osteoclastogenesis Inhibitory Activity in Bone Marrow Stromal Cells from Ovariectomized Rats
Authors: Wang Feng-Sheng , Wang Ching-Jen , Chen Yeung-Jen , Huang Yu-Ting , Huang Hui-Chen , Chang Per-Rong , Sun Yi-Chih , Yang Kuender D.
Published: February 2004

Nitric oxide (NO) has emerged as a potent regulator useful in alleviating estrogen deficiency bone loss. Osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) play important roles in regulating osteoclastogenesis. Although recent studies have reported NO donor attenuation of bone loss, the effect of NO donor on OPG and RANKL expression of osteogenic stromal cells and bone microenvironment in ovariectomized rats is not fully understood. Here, we showed that optimal NO donor treatment [2,2′-(hydroxynitrosohydrazino)bis-ethanamine; 15 μm] increased OPG, but not RANKL, levels in bone marrow stromal cells from ovariectomized rats. NO donor augmentation of OPG synthesis was transcriptionally mediated. The stimulatory action of NO donor on OPG expression appeared to be regulated by tyrosine kinase-dependent activation of Cbfa1/Runx2 binding to the OPG promoter, because cell cultures pretreated with tyrosine kinase inhibitor (herbimycin A), but not with protein kinase A inhibitor (calphostain C) or protein kinase C inhibitor [(Rp)-cAMP] significantly reduced NO-augmented Runx2 activation and OPG levels. Conditioned medium from NO donor-treated cells inhibited macrophage-colony-stimulating factor and RANKL-induced osteoclast formation of macrophage-colony-stimulating factor-dependent bone marrow macrophages. Neutralization with anti-OPG antibodies abolished the inhibitory effect of conditioned medium on osteoclastogenesis. Immunohistochemical observation also showed that 2,2′-(hydroxynitrosohydrazino)bis-ethanamine increased OPG expression of osteochondral cells located at metaphyseal endosteum and calcified cartilage of proximal femurs in ovariectomized rats. These findings suggest that NO donor can be an alternative pharmacological strategy for regulating bone resorption.
Experimental and numerical investigation into useful wrinkling during aluminium alloy internal high-pressure forming
Authors: Lang L H , Yuan S J , Wang Z R , Wang X S , Danckert J , Nielsen K B
Published: February 2004

Internal high-pressure forming is a process for manufacturing lightweight components, especially automotive parts, with advantages of lower cost and weight reduction, better structural integrity and increased strength and stiffness over the conventional stamping process. One of the typical failure modes, including wrinkling, buckling and splitting, will occur through an unreasonable combination of the control parameters: the internal pressure and the axial punch feeding. In most previous papers, wrinkling is considered to be a failure mode. However, not all wrinkles are defects. The collection of materials in an expanding area by the formation of wrinkles is an alternative method for obtaining a preformed shape in the hydroforming die. In this case, the key point is to obtain ‘useful’ wrinkles instead of ‘bad’ wrinkles. In this paper, an investigation will be conducted on how to control the shape of the wrinkle waves and its effect on the thickness distribution after hydroforming by using finite element simulation. LS-DYNA finite element software is used in this paper. An experiment has been carried out and the results obtained from experiment and simulation are in good agreement.
Dimensional accuracy of injection-moulded components produced in an enhanced silicone rubber mould
Authors: Dunne P , Byrne G
Published: February 2004

The inherent technical limitations of rapid prototyping systems have led to the development of rapid tooling techniques. These techniques are capable of producing prototypes in final materials by the intended manufacturing process. One rapid tooling process that provides a low cost and rapid route to the manufacture of injection-moulded thermoplastic components is enhanced silicone moulding. During the moulding cycle the mould deforms under the pressures and temperatures experienced and components produced suffer a loss of dimensional accuracy.

An analytical and experimental investigation was undertaken to quantify the dimensional accuracy of components produced by the process, and to identify the moulding parameters which contribute to the loss of dimensional accuracy. A mould was produced from a stereolithography master pattern and used to injection-mould components in high-impact polystyrene under various moulding conditions. Moulded components produced were typically oversized with a loss of dimensional accuracy of the order of 0.3–0.6 mm. Two parameters, namely injection pressure and mould temperature, were found to have an influence on dimensional accuracy.

The injection pressure causes the mould cavity to expand and results in manufacture of components which are oversized. Components produced at an injection pressure of 16MPa were on average 0.34 mm (1.3 per cent) oversized in width and 0.36 mm (11.3 per cent) oversized in depth. Those produced at an injection pressure of 20 MPa were oversized by an average of 0.45 mm (1.8 per cent) in width and 0.59 mm (18.6 per cent) in depth. An increase in mould temperature caused a reduction in the size of the mould cavity. This was because the rubber mould was restricted in a metal mould frame. The rubber mould expands into the free space of the cavity. Components produced at mould temperatures of 50, 70 and 90°C were oversized in width by an average of 0.37mm (1.5 per cent), 0.34 mm (1.3 per cent) and 0.20 mm (0.8 per cent) respectively.
A virtual prototyping approach to generation and evaluation of mechanical assembly sequences
Authors: Yin Z-P , Ding H , Xiong Y-L
Published: February 2004

It is desirable to integrate assembly planning with design early in the product development process. Usually, assembly plans can be generated by using either automated or interactive approaches. However, both kinds of approach have limitations. Interactive approaches require extensive user input in the tedious form of answering questions, whereas automated approaches can only be applied to products with simple component configuration and geometry. Based on virtual prototyping (VP), an intuitive and efficient approach is proposed for assembly planning by combining the potential strengths of the two kinds of approach. The main idea of this approach is to extract human expertise of mechanical assembly from human-computer interaction, and then use it for the automatic generation and interactive evaluation of assembly sequences. To incorporate expert knowledge, one or a few initial sequences are firstly created in a lesson by showing the way using the human-computer interface of virtual reality, where some intuitive and meaningful information such as motion path and assembly tool is captured automatically. Then, after representing assembly constraints as precedence expressions by reasoning about these initial sequences, all feasible sequences are generated efficiently based mainly on simple symbolic reasoning in place of costly geometric reasoning. In this way, the complexity of assembly sequence planning is reduced dramatically from seeking paths in a high-dimensional state space to a discrete graph-based searching problem. Finally, practical or good sequences are selected from the feasible sequences by exploiting the VP intuitive manipulation capability for judging the cost of a particular assembly operation. In the present authors’ experience, VP-based interaction has been proven to be a powerful and intuitive paradigm for both generation and evaluation of assembly plans. The feasibility of the proposed method is demonstrated through an implemented prototypical system called VPASPE, which has been tested with some practical assemblies.
Adaptive tool path generation from measured data
Authors: Yin Z
Published: February 2004

Conventional algorithms for tool path generation from measured points did not use the region-by-region idea to generate adaptive tool paths since it is difficult to obtain geometric information of scattered points directly, which is necessary for adaptive tool path generation. This paper presents a new strategy for determining geometric information of physical parts measured and then three-axis numerically controlled (NC) adaptive (region-based) tool paths that overcome the inherent drawback (redundant tool paths) can be directly generated from measured points. A new algorithm for computing offsets of B-spline surfaces constructed using chosen point data as control points is also proposed in the paper.
Machine tool errors caused by optical linear encoders
Authors: Alejandre I , Artes M
Published: February 2004

Position measurement in machine tools is usually carried out through rotary or linear encoders. Quite often, it is considered that part dimensional errors are only due to direct strain, thermal or vibration effects in the machine tool structure. There is, however, another important source of error: the encoder itself. This paper is intended to recognize, classify and determine the value of the different kinds of error in optical linear encoders: strain and displacement errors, thermal errors and errors caused by vibrations. The error identification will also permit a better understanding of some of the limitations that appear in the use of these devices.
Systematic retrofit design for manufacture’ critical component substitution in machine design
Authors: Edwards K L
Published: February 2004

Designing to substitute components is a regular activity in the process of improving the function, whether it is planned or the result of a failure of an existing product, assembly or machine. While this may not create an optimal design configuration, it does maintain the continuity of production and economics of the rest of the machine. The replacement of an existing component or components, however, cannot be done in isolation from the rest of the machine. Designing for component substitution or retrofit design needs careful consideration of all the interfacing components as well as some adjacent components, depending on the circumstances. The consequence of not taking into account all the effects of component substitution could potentially lead to detrimental performance or the worsening of the effect intended. This paper describes a systematic approach to retrofit design through a case study of the feasibility of replacing a key set of components in a machine in order to improve its performance.
Prediction and reduction of process times for the PC-based computer numerically controlled drilling machine
Authors: Onwubolu G C , Kumar S
Published: February 2004

Time is an important factor to consider in any manufacturing process and is related to the cost of the product. Thus, this paper presents an approximate method of predicting process times for the PC-based computer numerically controlled (CNC) drilling machine developed in-house. The paper presents a model for the process time components for the PC-based CNC drilling machine, which includes the movement of workpiece times and the actual drilling time. The process times for drilling different parts were predicted and compared with the actual times taken. The results obtained show that the drilling prediction times presented in this paper are very close to the actual times taken. The paper also shows that inclusion of a neuro-optimizer for sequencing a large number of points to be drilled could reduce the drilling time of operations. The prediction model is a useful tool for operations managers and manufacturing engineers in anticipating production times of products where drilling is involved.
Converting a deep-water access reconnaissance television into an autonomous underwater vehicle
Authors: Carnegie D A , King J C
Published: February 2004

This paper describes the re-engineering process involved in converting a manually controlled deep-water access reconnaissance television (DART) into an autonomous underwater vehicle (AUV). Such a conversion required the rebuilding of the DART's motors, redesigning the motor drivers, the installation of a new camera system, and a complete redesign of the electronics including the implementation of a modern computer motherboard. Mechanical modifications were necessary to install a set of underwater lights, and also to improve the portability and serviceability of the vehicle.
Diffusion of the intermittency across the boundary layer in transition
Authors: Gibbings J C
Published: February 2004

A physical model for the outward diffusion of the intermittency through boundary-layer transition is presented. The resulting analytical solution is tested against experimental measurement with encouraging results. Unusually, this solution for a turbulent flow is obtained without the introduction of any empirical coefficients of the turbulence other than the starting origin to the solution and the value of the viscosity.
Primary creep behaviour of polyester resins from multiple relaxation curves
Authors: Oliveira L C , Gomide H A , Rade R S L
Published: February 2004

Typical primary creep behaviour of a viscoelastoplastic material is shown when varying the temperature and the time rate of strain (of a previous tension). The creep behaviour is obtained from the tension test with multiple relaxations, where a numerical procedure is used in order to obtain creep curves from a series of relaxation curves. This test methodology allows interrelated tension, relaxation and creep behaviours to be obtained from one single test. The materials tested are proportional to the weight mixtures of rigid/flexible polyester resins with hardeners, generally used as model materials in photomechanics. With the increase in temperature, there is a decrease in the time needed to reach a given creep strain. The time rate of the strain, used in the tensions prior to the relaxations, has a considerable influence on the beginning of the relaxations. Since the creep curve is obtained from these relaxations, the rate of strain is shown to have an influence on creep behaviour, depending on the portion of the relaxation curve from where values are taken for calculation of creep.
Air-conditioning characteristics of the human nose
Authors: Wolf Michael , Naftali Sara , Schroter Robert C. , Elad David
Published: February 2004

Nasal inspiration is important for maintaining the internal milieu of the lung, since ambient air is conditioned to nearly alveolar conditions (body temperature and fullysaturated with water vapour) upon reaching the nasopharynx. This literature review of the existing in vivo, in vitro and computational studies on transport phenomena that take place within the human nasal cavity summarizes the current knowledge on air-conditioning characteristics of the human nose.
Randomized controlled trial on the treatment of otitis externa with one per cent silver nitrate gel
Authors: van Hasselt Piet , Gudde Hugo
Published: February 2004

Otitis externa (OE) and especially otomycosis can be very persistent and difficult to control. In the present study the efficacy of treatment of OE with a single instillation in the ear canal of one per cent silver nitrate in three per cent hypromellose gel compared to 0.1 per cent silver nitrate gel was tested in a single-blinded randomized controlled parallel group study. The outcome measure was complete resolution of the OE after one week. Forty-four patients with refractory, bacterial as well as fungal, OE entered the study, comprising 30 ears in each treatment arm. Eight patients defaulted from follow-up,five ears in each treatment arm. A single instillation of one per cent silver nitrate gel cured 23 (92 per cent) of 25 ears with OE, whereas with 0.1 per cent silver nitrate gel seven (28 per cent) of 25 ears treated were cured (Fisher-exact test, p-exact = 0.00010). In a non-controlled series of 120 ears 93.3 per cent needed only a single instillation of one per cent silver nitrate gel while another five per cent were cured after a second instillation a week later. There were no adverse reactions. OE can be treated effectively with instillation of one per cent silver nitrate gel and is particularly useful in recalcitrant otomycosis. The treatment method saves both cost and time.
Anti-inflammatory effect of erythromycin on histamine-induced otitis media with effusion in guinea pigs
Authors: Aktan Bülent , Gundogdu Cemal , Ucuncu Harun , Unal Bunyami , Sütbeyaz Yavuz , Altas Sare
Published: February 2004

In this study, the anti-inflammatory effect of erythromycin was investigated in a model of histamine-induced otitis media with effusion (OME). OME was induced in guinea pigs by the transtympanic injection of histamine solution into the middle-ear cavity. Guinea pigs were randomly assigned to one of three groups: control, erythromycin treatment, or methylprednisolone treatment. After histamine injection, the animals were treated with intraperitoneal medication for five days consecutively. Afterwards, the animals were sacrificed and the temporal bones were removed. The samples were examined stereologically.

In the erythromycin-treated group, it was observed that neutrophil infiltration was significantly inhibited when compared to the control group. This result shows that erythromycin may produce a significant anti-inflammatory effect in this model of OME.
Effects of the chorda tympani damage on submandibular glands: scintigraphic changes
Authors: Yagmur C. , Miman M. C. , Karatas E. , Akarcay M. , Erdem T. , Ozturan O.
Published: February 2004

The aim of this study is to compare the scintigraphic results of a denervated submandibular gland with the contralateral normal side in patients with unilateral chorda tympani damage. Sixteen patients (11 women and five men with a mean age of 27) with unilateral proven chorda tympani damage during their previous ear surgery were included in the study. The perfusion ratio (PR), concentration ratio (CR) and stimulated excretion ratio (SER) were calculated scintigraphically and the results from the salivary glands on opposite sides were compared.

For submandibular glands, the perfusion ratio (PR), concentration ratio (CR) and stimulated excretion ratio (SER) were found to be 0.65 ± 0.21, 0.70 ± 0.21, 0.79 ± 0.37, respectively. All ratios resulted from statistically decreased radioactivity accumulation on the affected side (p<0.05).

Chorda tympani damage negatively affects the function of the ipsilateral submandibular glands despite the absence of atrophy. Dynamic salivary gland scintigraphy is a practical and valuable method of disclosing the decreased capacity of perfusion, concentration and secretion function in unilateral neurological deprivation.
Clinical evaluation of the vector algorithm for neonatal hearing screening using automated auditory brainstem response
Authors: Keohane Bernie M. , Mason Steve M. , Baguley David M.
Published: February 2004

A novel auditory brainstem response (ABR) detection and scoring algorithm, entitled the Vector algorithm is described. An independent clinical evaluation of the algorithm using 464 tests (120 non-stimulated and 344 stimulated tests) on 60 infants, with a mean age of approximately 6.5 weeks, estimated test sensitivity greater than 0.99 and test specificity at 0.87 for one test. Specificity was estimated to be greater than 0.95 for a two stage screen. Test times were of the order of 1.5 minutes per ear for detection of an ABR and 4.5 minutes per ear in the absence of a clear response. The Vector algorithm is commercially availablefor both automated screening and threshold estimation in hearing screening devices.
Noise induced hearing loss in dance music disc jockeys and an examination of sound levels in nightclubs
Authors: Bray Adam , Szymański Marcin , Mills Robert
Published: February 2004

Noise exposure, hearing loss and associated otological symptoms have been studied in a group of 23 disc jockeys using a questionnaire and pure tone audiometry. The level of noise exposure in the venues where they work has also been studied using Ametek Mk-3 audio dosimeters. Three members of the study group showed clear evidence of noise-induced hearing losson audiometry, 70 per cent reported temporary threshold shift after sessions and 74 per cent reported tinnitus. Sound levels of up to 108 dB(A) were recorded in the nightclubs. The average level for a typical session was 96 dB(A) which is above the level at which the provision of ear protection is mandatory for employers in industry. It can be concluded that DJs are at substantial risk of developing noise-induced hearing loss and noise exposure in nightclubs frequently exceeds safe levels.
Sudden sensorineural hearing loss following intramuscular administration of penicillin
Authors: Escada Pedro Alberto , Capucho Clara , Madeira da Silva José Francisco
Published: February 2004

We report a case of sudden hearing loss in a patient with acute exudative tonsillitis, occurring 15 minutes after the intramuscular administration of penicillin. Audiological evaluation documented a profound sensorineural hearing loss of the cochlear type. The mechanism of the hearing loss was probably an immediate hypersensitivity (type I) allergic drug reaction. Penicillin is used frequently for the treatment of several infections. Allergic reactions to penicillin are well known and include urticaria, maculopapular exanthems, angio-oedema, bronchospasm and anaphylaxis, but sudden hearing loss has never been recorded.
Ball valve nasal obstruction following incomplete inferior turbinectomy
Authors: Magarey M. J. R. , Jayaraj S. M. , Saleh H. A. , Sandison A.
Published: February 2004

An interesting case is presented of a 53-year-old male who was seen with a 10-year history of intermittent, unilateral nasal obstruction following a bilateral total inferior turbinectomy. A pedunculated mass was seen in the right posterior nasal space acting as a ball valve. This was removed and found to be residual turbinate tissue.
Extracranial internal carotid artery aneurysm presenting as symptomatic hypoglossal and glossopharyngeal nerve paralysis
Authors: Wilding L. J. , Howlett D. C. , Anderson H. J. , Sangle P. D. , Violaris N. , Evans G. H.
Published: February 2004

Aneurysms of the extracranial portion of the internal carotid artery are rare, particularly in young patients. They usually develop following trauma, or secondary to infection involving the parapharyngeal space that extends to the vessel wall. This is a case of an internal carotid artery aneurysm presenting acutely following chiropractic neck manipulation with hypoglossal and glossopharyngeal nerve palsy. The imaging findings and subsequent operative management are described.
Reidel’s thyroiditis and Tolosa-Hunt syndrome, a rare association
Authors: Khan M. A. B. , Hashmi S. M. H. , Prinsley P. R. , Premachandra D. J.
Published: February 2004

A previously undescribed association of Reidel’s thyroiditis with Tolosa-Hunt syndrome is reported. A 33 year-old Caucasian female presented with a two-year historyof painful progressive goitre, histologically a Reidel’s thyroiditis. She underwent left partial thyroidectomy. Post-operatively she developed severe right retro-orbital pain, right temporal headache and a partial right occulomotor nerve palsy. A diagnosis of Tolosa-Hunt syndrome was made. Some important aspects of this case are discussed.
Pulsatile tinnitus as a rare presenting symptom of residual cholesteatoma
Authors: Falcioni M. , Taibah A. , Rohit
Published: February 2004

Pulsatile tinnitus is an uncommon otological symptom, which often presents a diagnostic and management dilemma to the otolaryngologist. This symptom always deserves a thorough evaluation to avoid disastrous consequences from potentially life-threatening associated pathology. In most of the patients a treatable underlying aetiology can be identified. Frequentcauses mentioned in the literature responsible for pulsatile tinnitus are benign intracranial hypertension syndrome, temporal bone paragangliomas and arteriovenous fistulae. Pulsatile tinnitus as a consequence of sigmoid sinus compression by a cholesteatoma has not been reported previously in the literature. Here a case of residual cholesteatoma with pulsatile tinnitus is presented, nine years after the first surgery.
Predicting length of stay for Medicare patients at a teaching hospital
Authors: Omachonu V. K. , Suthummanon S. , Akcin M. , Asfour S.
Published: February 2004

This research examines how the patients' characteristics and clinical indicators affect length of stay for the top five Diagnosis-Related-Groups (DRGs) for Medicare patients at a teaching hospital in the United States. The top DRGs were selected on the basis of volume per year. Teaching hospitals in the United States devote a significant amount of their resources to research and teaching, while providing treatment for patients. The ability to predict length of stay can substantially improve a teaching hospital's capacity utilization, while ensuring that resources are available to meet the health care needs of the Medicare population. Multiple regression models are developed to predict the length of stay using the patients' characteristics and clinical indicators as independent variables. The results indicate that approximately 60 percent (R2) of the variance in the length of stay is explained by the patients' characteristics and clinical indicators for these DRGs. The Mortality and Severity indices are found to be the strongest predictors for length of stay in all DRGs. Other patients' characteristics and clinical indicators such as age, gender, race/ethnicity, marital status, admission type and admission source are also significant predictors for some DRGs. In addition, most of these variables affect the length of stay in the same manner as shown in previous studies, even though the previous studies do not have the DRG specificity of this study.
Organizational and market factors associated with Medicare dependence in inpatient rehabilitation hospitals
Authors: Thompson J. M. , McCue M. J.
Published: February 2004

Rehabilitation hospitals in the USA have been excluded from the Medicare Prospective Payment System (PPS) system since 1982, and have received cost-based reimbursement. However, the 1997 Balanced Budget Act mandated a PPS for inpatient rehabilitation, to be implemented by the end of 2002. This study assesses rehabilitation hospitals' dependency on Medicare. Findings show that not-for-profit hospitals, facilities with fewer services, facilities with lower staffing levels, and hospitals with lower operating expenses and profits, have a higher proportion of their inpatient revenue coming from Medicare. These facilities may be vulnerable to the new PPS payment system.
Clinician managers and cultural context: comparisons between secondary and primary care
Authors: Willcocks S. G.
Published: February 2004

This paper takes account of earlier work suggesting that cultural differences between clinical specialties in the hospital sector are an important indicator of the extent to which different specialities are able to engage successfully with managerial roles. This study suggested that some clinical specialties, particularly non-acute and support specialties, were more predisposed to managerial work, whereas acute clinical specialties, for example, surgical specialties, or obstetrics, tended to be more sceptical and in some cases antagonistic towards managerial work. These findings are compared with the emerging experiences of GPs faced with the challenge of similar managerial situations. The findings point to the existence of different cultural groups, or subcultures, co-existing in both the Trust and to some extent in the PCG. Some clinical specialties were prepared to share managerial values and expectations or at least go along with them, while others were antagonistic and represented a potential source of conflict. The evidence in the two sets of data points to two broadly defined groups: traditional professional and managerialist subcultures. The existence of these cultural sub-groupings is significant in terms of support for or against doctor involvement in the managerial process.
Satellite-Based Wind Maps as Guidance for Siting Offshore Wind Farms
Authors: Furevik B. R. , Espedal H. A. , Hamre T. , Hasager C. B. , Johannessen O. M. , Jørgensen B. H. , Rathmann O.
Published: February 2004

Offshore wind farms have started to contribute important supplies of renewable energy. The energy production of a wind farm depends upon the local wind climate and so may be predicted in advance. Usually, the prediction is based on at least one year of accurate wind measurements. Satellite Synthetic Aperture Radar (SAR) wind mapping can be a useful tool in selecting optimal sites and may therefore increase the cost-effectiveness of planning wind farms, e.g., in feasibility studies. In the WEMSAR project1 wind fields from SAR, in situ measurements and model output from three test-sites have been analysed [1]. Subsequently, a WEMSAR tool for effectively retrieving wind data from SAR images and utilising them in the WAsP micrositing model, has been developed. Testing of the WEMSAR tool at Horns Rev offshore wind farm in Denmark is ongoing.
Horns Rev Offshore Windfarm: Its Main Controller and Remote Control System
Authors: Kristoffersen Jesper R. , Christiansen Peter
Published: February 2004

This paper describes the Windfarm Main Controller and the Remote Control System in the Horns Rev Offshore Windfarm. It begins with a brief description of the windfarm and proceeds to discuss the conditions for connecting the farm to the grid. The description of the Windfarm Main Controller describes the different control modes in the windfarm and shows some recorded measurements. The paper also presents the remote control system. Because of the size and location of the windfarm, it was necessary to introduce a main control concept as in conventional power plants, so to control the output and for maintenance.
The DOWEC Offshore Reference Windfarm: Analysis of Transportation for Operation and Maintenance
Authors: van Bussel G.J.W. , Bierbooms W.A.A.M.
Published: February 2004

The Dutch Offshore Wind Energy Converter project (DOW EC) aims to design large wind turbines for application in large-scale offshore farms. A baseline windfarm has been considered 43 km off the Dutch coast, with 80 wind turbines, each of 6 MW capacity. In this paper, access methods for O&M crew have been investigated. The methods include: (i) inflatable boats (zodiacs), (ii) special offshore access systems and (iii) helicopters. For the methods considered, operational limits have been established, expressed as ‘maximum-mean’ wind speed and as significant wave height. On the basis of the NEXT database the statistics of the corresponding weather-windows have been determined. These statistics, together with the failure statistics and the regular maintenance dem and of the wind turbines and the other offshore windfarm components determine its overall-availability at the specific site. Estimates of this overall-availability of the offshore windfarm have been obtained with a sophisticated Monte Carlo simulation model of the operations within the windfarm. The simulations show that use should be made of access methods with which an accessibility of at least 82% of time can be achieved. This rules out standard options, e.g. direct inflatable boat access, in order to maintain a windfarm availability greater than 90%.
The Effect of Large Offshore and Onshore Wind Farms on the Frequency of a National Power Supply System; Simulation Modelled on Germany
Authors: Koch Friedrich , Erlich Istvan , Shewarega Fekadu , Bachmann Udo
Published: February 2004

The paper describes the simulated effect of large windfarms on the frequency of the interconnected grid system within which they are operating. The study is modelled on Germany. The features of the well-tested and widely used power system simulation package Power System Dynamics (PSD) were expanded so that windfarms with all commonly used wind turbine generators and their control structures can be simulated. In particular, the windfarm interaction with the power grid can be studied. Additionally, the effects of topology and wind conditions at the location of the wind turbines on the output power have been incorporated into the simulation. The result reveals that the stochastic nature of wind power at significant capacity may cause noticeable frequency fluctuation on the whole grid. Without countermeasures, the fluctuating power may use a disproportionately large component of the primary control power reserve of the grid system. The paper describes options for the integration of large offshore and onshore windfarms in the task of primary frequency control.
Feasibility Study of Floating Windfarms in Shallow Offshore Sites
Authors: Henderson Andrew R. , Bulder Bernard , Huijsmans Rene , Peeringa Johan , Pierik Jan , Snijders Erik , van Hees Martin , Wijnants Geert H. , Wolf Martijn J.
Published: February 2004

This paper reports on a feasibility study of potential floating structures suitable for wind turbines in shallow seas (around 50 m). It describes the concepts, the evaluation and the selection process and includes ancillary issues, such as grid connection and O & M. Finally, it reports detailed analysis of the concept selected as most suitable in the circumstances, namely, a ‘triple-floater’ construction. A main conclusion is that although, in this case, this technology may not yet be ready for commercial application, the gap to economic viability is closing.
Primary Markets for Offshore Wind Energy outside the European Union
Authors: Siegfriedsen S. , Lehnhoff M. , Prehn A.
Published: February 2004

As part of the development of offshore wind energy systems, the engineering firm ‘aerodyn Engineering GmbH’ examined the world-wide potential for the primary markets in large-scale use of offshore wind energy outside the European Union. The countries considered already have sufficient onshore grid demand to accept, in principle, the offshore power. The results have been published in a comprehensive study, summarised in this paper. The main conclusion, based on the assessment scheme applied to the countries outside the EU, is that there are suitable sites, with a total area of about 275,000 km2, for the primary market for offshore wind energy into established grid demand. These areas would accommodate nearly 330,000 wind turbines, each of 5 MW capacity. The total electricity production would be about 4,600 TW h/y. This is the equivalent of more than a quarter of the world's present electricity demand.
Finite Element Analysis of Steel-Concrete Composite Girders
Authors: El-Lobody Ehab , Lam Dennis
Published: February 2004

Finite element models for the analysis of solid slabs and precast hollow core slabs composite girders are presented. For both models, 8-node three-dimensional solid elements are used in the analysis. The material non-linearity of all components of the composite girders is taken into consideration. The non-linear load-slip characteristics of the headed shear stud connectors are included in the models. The models predict load – deflection behaviour and stress distribution along the length of the beam. Good agreement is obtained between the models and results previously published.
An Analysis of Current Stability Theories for Thin-Walled Members
Authors: Tong Gengshu , Zhang Lei
Published: February 2004

There are two different formulae available for calculating the critical moments of thin-walled beams under transverse loads. They give quite different results for beams with monosymmetrical cross-sections. This paper reviews the stability theories for thin-walled beams and identifies some points which might be present and have led to the current situation of the buckling moment formulae for the beams. Finally a new theory proposed by the authors is briefly introduced and a rational way for establishing a general buckling theory for thin-walled members is proposed.
A General Theory for the Flexural-Torsional Buckling of Thin-Walled Members I: Energy Method
Authors: Tong Gengshu , Zhang Lei
Published: February 2004

There exists two different theories on the flexural-torsional instability of the thin-walled members, and based on them, very different results for beam elastic buckling can be obtained. In this paper, a new theory is presented to solve the inconsistency between the two different theories noted above after very deep investigation. In this new theory, the transverse stress is introduced as an important factor for member stability, in addition to the longitudinal and shear stresses and strains already considered in the work of others. The energy method was used to derive the general theory in this paper. Based on the variational principles, the nonlinear potential energy of the external loads is excluded.
Nonstationary Response of Bridge Due to Eccentrically Moving Vehicles at Variable Velocity
Authors: Sasidhar M. N. V. , Talukdar S.
Published: February 2004

The non-stationary response of a simply supported girder bridge induced by the vehicle travelling at variable speed has been studied. The deck unevenness has been considered as the realization of homogeneous random process described by power spectral density (PSD) function. The vehicle has been idealized as rigid beam connected by front and rear suspension elements moving at an eccentricity with the centre line. The bridge has been idealized as a continuous system with distributed mass, stiffness and damping properties having flexural and torsional degrees of freedom. Monte Carlo simulation technique has been used to simulate deck profile for generation of input samples in numerical integration of the system equations. A detailed parametric study has been conducted to examine the effect of variable speed, suspension characteristics, vehicle mass, eccentricity of vehicle path, torsional rigidity of the bridge and deck unevenness on the dynamic amplification factors of the response.
Flexural Wrinkling Strength of Lightly Profiled Sandwich Panels with Transverse Joints in the Foam Core
Authors: Mahendran M. , McAndrew D.
Published: February 2004

In Australia, sandwich panels are commonly made of flat or lightly profiled steel faces and expanded polystyrene foam cores, and are increasingly used as roof and wall claddings in industrial and commercial buildings. Flexural wrinkling is often the governing criterion in the design of these panels. The use of lightly profiled faces is expected to increase the flexural wrinkling stress considerably whereas the presence of joints between the polystyrene foam slabs in the transverse direction introduces a reduction to the flexural wrinkling stress. Therefore a series of full scale experiments and finite element analyses were conducted to evaluate the effects of lightly profiled faces and transverse joints on the flexural wrinkling stress of panels subjected to a lateral pressure loading. The results showed that properly designed lightly profiled panels provided considerable improvement to flexural wrinkling strength over flat panels whereas the presence of transverse joints caused a significant reduction to wrinkling strength. This paper presents the details of this investigation, the results and comparison with available theoretical and design solutions.
Non-Linear Performance of Slabs in Coupled Shear Wall Structures
Authors: Hossain Khandaker M. Anwar
Published: February 2004

The non-linear coupling action of reinforced concrete slabs in shear wall structures is investigated by the finite element method and the results are validated by small scale model tests using micro-concrete. Flexural stiffness and effective width of the coupling slabs are found to be influenced by the geometric and non-linear material parameters of the structures. Design curves for the determination of flexural stiffness and effective width are presented as functions of geometric parameters in the pre-cracking, cracking and post-yielding stages of non-linear material response. Comparative study of numerical and experimental results suggested that the design curves are reliable and can be used in the analysis and design of shear wall structure in practical situations.