bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive sliding mode control robust to actuator faults
Authors: Hwang T W , Tahk M-J , Park C-S
Published: February 2007

An adaptive sliding mode control (SMC) algorithm is developed for a missile with highly non-linear aerodynamics. Conventional SMC algorithms have inherent robustness to system model errors, but they often induce chattering of the actuator commands. An adaptive switching gain based on the Lyapunov stability theory is proposed to mitigate the chattering in the steady state. The gain varies with respect to the distance from the sliding surface. The controller with the adaptive switching gain also has robustness to system model errors and unexpected changes in aerodynamic coefficients. A control command generation method using the estimated actuator characteristics is proposed. The proposed method avoids the control performance degradation caused by actuator fault or model disagreement. The effectiveness of the proposed control algorithm is verified through numerical simulations.
Practical guidance law controlling impact angle
Authors: Kim K-S , Jung B , Kim Y
Published: February 2007

Impact angle is defined as the angle between the velocity vectors of a missile and a target at the instance of interception. The objective of the impact angle control guidance (IACG) law is to guide the missile into a collision course with a specified impact angle. In this paper, a new IACG law considering practical implementation is proposed. By selecting parameters properly, the proposed guidance law can be applied to various engagement situations such as the rear-chase case and the face-to-face case. On the basis of the backstepping control approach, the proposed guidance law only requires information about the impact angle, the line-of-sight rate, and the estimated time-to-go. These features improve the applicability of the proposed guidance law to the real systems. To verify the performance of the proposed guidance law, two-dimensional engagement problem is considered. Numerical simulation results demonstrate that the proposed guidance law is effective for controlling the impact angle.
Numerical analysis of heterogeneous combustion in a ducted rocket
Authors: Salvá J J , Tizón J M , Jenaro G , Agudo C López
Published: February 2007

A model to analyse the heterogeneous combustion process that takes place in an axisymmetric combustor of an air ducted rocket is presented, including radiation. The fuel, injected into the combustor through a simple injector, is a mixture of gaseous products, carbon particles, and MgO inert particles that results from the combustion of a solid fuel (HTPB-AP-Mg). The turbulence model used is the realizable k—π model. The adopted reaction model is a reduced kinetic scheme composed of five reactions, three in gaseous phase and two heterogeneous. The model ‘finite rate/eddy dissipation model of Magnussen and Hjertager’ is used to calculate the production terms in the gas phase, meanwhile the mixed model of Field, Baum, and Street is used for the oxidation reaction of carbon particles.

After a detailed analysis of the numerical results, obtained with a commercial code for a specific combustor geometry and one set of boundary conditions both for the gaseous and solid phases, the existence of a special combustion pattern is found. It is composed of a turbulent diffusion jet flame attached to the injector, where only the gaseous fuel is burned, followed by a reaction region that envelops the jet of carbon particles at the aft of the combustion chamber. This jet of carbon particles oxidizes at a finite rate producing CO and CO2. The emission of CO and C(s) from the combustor is the main cause of high efficiency reduction.

Radiation has little effect on calculated global variables, such as efficiency, mass flowrate, and total pressure loss, but on the contrary its effects on the temperature fields became important. Chilling of the gas phase was observed together with a reduction of solid particle temperature, however wall combustor temperature increased greatly.

Simulation results are interpreted in the light of experimental observations and available numerical solutions in the literature.
A de-coupled approach to component high-fidelity analysis using computational fluid dynamics
Authors: Pachidis V , Pilidis P , Templalexis I , Barbosa J B , Nantua N
Published: February 2007

This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. The technique described in this paper is called ‘de-coupled’ high-fidelity analysis and utilizes an object-oriented, zero-dimensional gas turbine modelling and performance simulation system and a three-dimensional computational fluid dynamics (CFD) component model. The technique involves the generation of a component characteristic map without the parallel or iterative execution of the non-dimensional cycle and the three-dimensional CFD model. Therefore, a faster high-fidelity engine performance simulation can be achieved at run time. This paper demonstrates the ‘de-coupled’ approach to component high-fidelity analysis by using a three-dimensional CFD intake model of a high by-pass ratio turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The CFD-generated performance map can fully define the characteristics of the intake at several operating conditions and power settings, and is subsequently used to provide a more accurate, physics-based estimate of intake performance (i.e. pressure recovery) and hence, engine performance, replacing the default, empirical values within the non-dimensional cycle model. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the CFD-generated map is presented in this paper. The analysis carried out by this study demonstrates relative changes in the simulated engine performance > 1 per cent.
An evaluation of the whole-spacecraft passive vibration isolation system
Authors: Jun Z , Hongxing H , Zhiyi Z
Published: February 2007

The launch environment, which typically lasts only a few minutes, is the most severe dynamic environment, that the spacecraft will experience during its normal mission life. Reduction of launch-induced dynamic loads transmitted to the spacecraft will reduce the risk of failure of the spacecraft or its components on orbit, allow more sensitive equipment to be included in missions, and possibly reduce the quality control cost of the spacecraft. In this article, an experimental evaluation of the whole-spacecraft passive isolation system is presented with a demonstration unit consisting of a series of isolator elements inserted in the joints between the adapter and the launch vehicle. The payload attach fitting is treated with constrained viscoelastic layer on the outer surface to increase its damping. The experimental results show that the whole-spacecraft isolation system can decrease the vertical and lateral dynamic responses effectively. The isolation performance is evaluated by the acceleration peak response and the root mean square value in the frequency band from 5 to 150 Hz.
Thermomechanical investigation of the cortical bone analogue in third-generation Sawbones femurs
Authors: Bell C G R , Weinrauch P , Crawford R , Pearcy M
Published: February 2007

The mechanical properties of the short glass fibre reinforced (SGFR) epoxy resin used as the cortical bone analogue in the third-generation Sawbones femurs were investigated for use within orthopaedic benchtop tests. Tensile and four-point bending tests were used to assess the material properties of the SGFR epoxy at both room (22° C) and body temperatures (37° C). The 20 standardized specimens used for the materials testing were machined from third-generation Sawbones femurs. The flexural properties of the specimens were determined using ASTM D6272-02 and the tensile properties were obtained using ASTM D638-02.

The mean (and standard deviation, or SD) values of the modulus of elasticity in four-point bending for room and body temperature specimens of 7.8 (0.64) GPa and 2.8 (0.66) GPa respectively were significantly different ( P < 0.001). The mean (and SD) values of the modulus of elasticity in tension for the room and body temperature specimens of 9.4 (0.8) GPa and 5.4 (1.3) GPa respectively were also significantly different ( P = 0.02).

The modulus of elasticity of SGFR epoxy is highly temperature dependent. A reduction in the modulus of elasticity of up to 63 per cent was observed when increasing the temperature of the specimens from room to body temperature. SGFR epoxy Sawbones do not accurately represent the material properties of bone at body temperature.
Prosthetic devices: Challenges and implications of robotic implants and biological interfaces
Authors: Lai J C K , Schoen M P , Gracia A Perez , Naidu D S , Leung S W
Published: February 2007

Although among designs of prosthetics there have been some successes in the design of functional robotic implants, there remain many issues and challenges concerned with the failure to meet the ‘ideal’ requirements of a satisfactory prosthetic. These ‘ideals’ require the device to be easy to control, comfortable to wear, and cosmetically pleasing. Because the literature on prosthetics and robotic implants are voluminous, this review focuses on four topics to determine key challenges and opportunities underlying these interdisciplinary research areas: firstly, an artificial hand as a biomimetic; secondly, prosthetic implants (electromyography signals and control); thirdly, prosthetic implants and tissue reactions to the material(s) of implants; fourthly, how inflammatory responses of cells and tissues surrounding implanted sensors interfere with the signal transmission of such sensors. This review also notes the importance of the biological interfaces that robotic implants and other prosthetic devices are in contact with and how an improved knowledge of pathophysiological changes at such biological interfaces will lead to improved and more biocompatible designs of prosthetics. This review concludes with the vision that, to develop a design that satisfies the above ‘ideals’, an interdisciplinary team of biomedical and tissue engineers, and biomaterial and biomedical scientists is needed to work together holistically and synergistically.
Cationic surfactants and other factors that affect enzymatic activities and transport
Authors: Leung S , Gironella A , Trigo C , Bhushan A , Daniels C K , Lai J C K
Published: February 2007

Surfactants influence functions of proteins in cell signalling. Because molecular mechanisms of surfactants are poorly understood, the cationic surfactant effect on three metabolically important enzymes - L-glutamate dehydrogenase, L-lactate dehydrogenase, and L-malate dehydrogenase - were investigated at a physiologically relevant pH range (6.5-7.4). How a cationic, a non-ionic, and an anionic surfactant could differentially influence these enzymes, and how these surfactants could influence the interfacial mass transport of these enzymes across a polycarbonate membrane in a separation cell were also investigated. Provided the charge density was the same, cationic surfactants affected enzymatic activities similarly, regardless of their molecular masses. Hence, a cationic surfactant behaved similarly to a hydrophilic anionic surfactant; however, the cationic surfactant also enhanced enzymatic activity at pH 6.5 and a moderately high concentration (150 ppm). The hydrophilic surfactant enhanced enzymatic activity and the hydrophobic surfactant depressed enzymatic activity. Addition of 0.1 ppm of the hydrophilic anionic surfactant decreased the amount of enzyme permeation through the membrane, but 0.1 ppm of the non-ionic surfactant had no effect, whereas 0.1 ppm of the hydrophobic surfactant increased enzyme permeation. These results have physiological and signalling implications in nanobiotechnology.
Effect of partial substitution of diesel fuel by natural gas on performance parameters of a four-cylinder diesel engine
Authors: Saidur R , Jahirul M. I. , Moutushi T. Z. , Imtiaz H , Masjuki H. H.
Published: February 2007

This work presents the evaluation of some performance parameters with cost comparison for a four-cylinder diesel engine under a variety of operating conditions, before and after converting to dual fuel engine. The experiment used a converted dual fuel diesel engine which can run on a hybrid mixture of diesel and natural gas (NG). The focus of this study is on the engine thermal efficiency, exhaust gas temperature, lubricating oil temperature, air fuel ratio, specific fuel cost, and specific fuel consumption under different operating conditions. A comparison of the cost economy of pure diesel engine and gradually converted dual fuel engine is also performed. Performance parameters with engine power (kW) are compared as well. This study concludes that fuel cost can be reduced significantly by substituting diesel with NG. Few costly accessories are needed for converting stationary diesel engine into dual fuel engine without altering basic engine components. Other findings from this study include relation between brake thermal efficiency, brake specific fuel consumption, and other performance parameters of engine.
A new load frequency control technique for an isolated small hydropower plant
Authors: Doolla S , Bhatti T. S.
Published: February 2007

In this paper a new load frequency control technique for an isolated small hydropower plant is proposed. In general, the frequency of the system is controlled by employing a dump load, whose rating is equal to the rated power output of the plant. The scheme proposed reduces the size of the dump load to 50 per cent, as 50 per cent input power of the hydro plant is controlled by an on/off control. A generalized transfer function model for the system is developed with an on/off control logic, which linearly raises or lowers the generation. Finally, transient responses are shown for low, medium, and high head installations with different loading conditions.
Innovative procedure to minimize multi-row compressor blade dynamic loading using rotor-stator interaction optimization
Authors: Benini E , Toffolo A
Published: February 2007

This paper presents a two-dimensional two-objective procedure for minimizing dynamic loading and maximizing efficiency in multi-stage compressors. The procedure arises from the combination of an evolutionary algorithm and a CFD code, in which a sliding mesh technique and a time-dependent approach are implemented, enabling the study of unsteady rotor-stator interaction. The method is then applied to a two-stage compressor cascade (rotor-stator-rotor-stator). The results concerning the optimal set of geometrical parameters considered for optimization (axial distances between successive cascades, circumferential clocking between stators and between rotors) are finally presented and discussed.
Theoretical and experimental investigation of a hot box-type solar cooker performance
Authors: Özkaymak M
Published: February 2007

A box-type solar cooker with three reflectors hinged at the top of the cooker was used for the experimental data and a mathematical model. Energy-balance equations were applied to components of the cooker such as absorber plate, cooking vessel, cooking fluid, enclosure air inside the cooker, and glass cover. Then, Cramer's rule was used to solve the equations and build the models. The actual temperature distribution in Karabuk, Turkey recorded on a typical summer day was also calculated by computer simulation using the suggested model. The predicted temperatures agreed with measurements under transient conditions within about 3.2 °C for absorber plate, until the boiling point of water was reached, to + 1.8 °C for enclosure air, and within ±2.5 °C for cooking fluid. Good agreement between experimental and theoretical results was observed.
Transient elastohydrodynamic analysis of elliptical contacts. Part 3: Non-Newtonian lubricant solution under isothermal and thermal conditions
Authors: Cui J , Yang P , Jin Z. M. , Dowson D
Published: February 2007

Transient non-Newtonian elastohydrodynamic lubrication (EHL) of elliptical point contacts was investigated numerically under both thermal and isothermal conditions. The multi-level technique used in Parts 1 and 2 of this series of papers for determining pressure and film thickness and the column-by-column relaxation technique used in Part 2 for temperature calculation were used again in this study. However, both Newtonian and non-Newtonian lubricant properties were considered, with the Ree-Eyring model being adopted in the latter case. The entrainment direction was assumed to be along the minor axis of the contact ellipse. A simplified numerical scheme for the evaluation of the equivalent shear stress and viscosity of the non-Newtonian lubricant was proposed and verified by comparing the steady-state thermal solutions without the simplification. The computing time required for a transient thermal and non-Newtonian case was typically ∼14 h on a personal computer with a 2.8 GHz central processing unit. For a steel-steel contact, the responses of the EHL films to a transient load impulse were determined for the non-Newtonian lubricant under both isothermal and thermal conditions. The isothermal non-Newtonian results were compared with those in Part 1, and the thermal results were compared with those presented in Part 2. A similar investigation for a glass-steel contact is also reported.
Design analysis and experimental study of aerostatic linear guideways used in a high acceleration and high precision xy stage
Authors: Li Y. T. , Ding H
Published: February 2007

Profiting from its low friction, non-hysteresis, ease of manufacture and high motion accuracy, air bearings have been widely used in various precision or ultra-precision low acceleration stages. In this paper, a high acceleration and high precision xy stage using aerostatic linear guideways is designed and manufactured to meet the requirements of chip manufacturing equipment. During the design of these guideways, the parameters, such as orifice diameter, distribution of orifices and film thickness are determined by calculating load carrying capacity, tilt stiffness, and mass flowrate of the guideways using the finite-element method. The experimental results show that the performance of these guideways coincides very well with that of the numerical calculations and satisfies the requirements of the stage.
Thermohydrodynamic lubrication analysis for a dynamically loaded journal bearing
Authors: Michaud P , Souchet D , Bonneau D
Published: February 2007

A numerical procedure is developed to analyse the ‘three-dimensional transient thermohydrodynamic (THD)’ behaviour of bearings under dynamic loading. The Reynolds equation, the three-dimensional energy equation in film, and the three-dimensional heat transfer equation in solids are simultaneously solved using a Newton-Raphson procedure and finite-element modelling to resolve the three-dimensional THD problem. The three-dimensional finite-element meshes of the three domains are interconnected and, therefore, the heat flux continuity conditions become implicit. The developed numerical procedure incorporates a cavitation (mass conservation) algorithm on the basis of the JFO (Jacobson, Floberg, and Olsson) model, which automatically predicts film rupture and reformation in the bearings. In order to validate the three-dimensional model, the temperature fields are compared with the temperature fields obtained with a numerical two-dimensional THD model with a parabolic pressure in the axial direction and also with experimental results. Finally, this model is applied to a bearing under sinusoidal loading in which the oil supply is fixed on the housing.
Appendicectomy for recurrent and chronic appendicitis
Authors: Hassan Saidi , Chavda S K , Magoha G A
Published: February 2007

In recent years, several reports have underlined the possible existence of chronic appendicitis. Up to 38% of spontaneously resolving acute appendicitis may recur. We studied 41 patients operated on between July 2000 and June 2001 for chronic and recurrent appendicitis at a teaching hospital in the city of Nairobi. The patients comprised 17.8% of all patients undergoing surgery for appendicitis during the study period. The majority (65.9%) were females. The faecolith rate was 51.2%. About half of appendices removed for these symptoms were normal at histology. Nearly 70% of the normal appendices contained faecoliths. Symptoms resolved in 90% of faecolith-containing appendices and 87.5% of non-faecolith-containing appendices that were normal on histology.
The influence of economic factors on the location of birth among Palestinian women in Bethlehem during the second Palestinian uprising
Authors: Fujiya Rika , Jimba Masamine , Giacaman Rita , Nakahara Shinji , Ichikawa Masao , Wakai Sususmu
Published: February 2007

We investigated the impact of the Palestinians' economic support programmes and the influence of Israeli army invasions on the place of birth during the second Palestinian uprising. We collected data on the number of births by place from the Palestinian Ministry of Health and Holy Family Hospital (HFH) in Bethlehem and on Israeli army's invasions into Bethlehem. We then analysed these factors. We see the percentage of births in government hospitals increased after a new health insurance scheme was introduced in 2001. The number of births in HFH decreased during this period. Israeli army invasions also contributed to the decrease of births in HFH during April 2002. However, reducing the charge for delivery at HFH in December 2002 greatly increased the number of births there. We concluded that, in urban Bethlehem, although movement restrictions contributed to the change in the place of birth, economic support programmes have also contributed to offsetting the movement restriction effects.
Medication use in early pregnancy: a study in a teaching hospital in Western Nepal
Authors: Sarkar Chayna , Das Biswadeep , Datta Adrija , Bohra Sangeeta
Published: February 2007

This study explored the extent of drug use in early pregnancy (first trimester of pregnancy) in Nepalese women in the setting of a large teaching hospital in western Nepal.
Trends in road traffic crashes, casualties and fatalities in Malawi
Authors: Olukoga Abiodun
Published: February 2007

There were 58,858 road traffic crashes, 39,111 casualties and 8,504 fatalities reported in Malawi between 1987 and 1995. This represented a 31% increase in the number of road traffic crashes, 42% increase in the number of casualties and 105% increase in the number of fatalities during the study period.

The number of licensed vehicles in Malawi increased by 88%, from 43,762 to 82,218, and the number of road traffic crashes per 1000 vehicles decreased by 30% during the same period, from 118.9 to 82.9. The number of casualties per 1000 vehicles decreased by 30%, from 73.5 to 55.6, but the number of fatalities per 10,000 vehicles increased only slightly by about 12%, from 126.8 to 138.7.

Despite a 34% increase in the population of Malawi from 8 million to 10.7 million between 1987 and 1995, only minimal changes were reported in both the number of road traffic crashes per 10,000 population and the casualties per 10,000 population. But the number of road traffic fatalities per 100,000 population increased by 55%, from 6.9 to 10.7.
Efficacy of topical ophthalmic prophylaxis in prevention of ophthalmia neonatorum
Authors: Matinzadeh Zahra Khalili , Beiragdar Fatemeh , Kavemanesh Zohreh , Abolgasemi Hasan , Amirsalari Susan
Published: February 2007

Ophthalmia neonatorum is a form of conjunctivitis occurring in infants younger than 4 weeks. It can be a leading cause of blindness in newborns. In this random clinical case-control study, ophthalmia neonatorum was investigated in one university centre. In this study, prophylactic effect of normal saline and ophthalmic erythromycin was compared with a group not receiving any prophylaxis. The first group received ophthalmic erythromycin ointment (0.5%), the second group were distilled one drop of normal saline into each eye, and the third group did not take any prophylaxis. Within the first10 days of life, conjunctivitis developed in 138 newborns (13.8%). Of conjunctivitis cases, 29.7% were in erythromycin group, 31.9% in normal saline group and 38.4% were in no-prophylaxis group. In general, no significant difference was observed among the three groups ( P > 0.05).
Clinical screening for HIV in a health centre setting in urban Kenya: an entry point for voluntary counselling, HIV testing and early diagnosis of HIV infection?
Authors: Arendt V , Mossong J , Zachariah R , Inwani C , Farah B , Robert I , Waelbrouck A , Fonck K
Published: February 2007

A study was conducted among patients attending a public health centre in Nairobi, Kenya in order to (a) verify the prevalence of HIV, (b) identify clinical risk factors associated with HIV and (c) determine clinical markers for clinical screening of HIV infection at the health centre level.

Of 304 individuals involved in the study,107(35%) were HIV positive. A clinical screening algorithm based on four clinical markers, namely oral thrush, past or present TB, past or present herpes zoster and prurigo would pick out 61 (57%) of the 107 HIV-positive individuals.

In a resource-poor setting, introducing a clinical screening algorithm for HIV at the health centre level could provide an opportunity for targeting voluntary counselling and HIV testing, and early access to a range of prevention and care interventions.
Diagnosis of fasciola hepatica cases in an operating room
Authors: Bulbuloglu E , Yuksel M , Bakaris S , Celik M , Kokoglu O F , Kale I T
Published: February 2007

Fascioliasis is a zoonotic disease that is acquired by ingestion of the metacercaria form on uncooked aquatic plants, and humans act as an accidental host. Diagnosis is confirmed by the demonstration of the parasites or evidence of them in faeces and serology. In the absence of these data, delays or misdiagnosis may occur since it may mimic many diseases. In this study, we present three cases, among them two were similar to the above-mentioned statement. The first case, to the best of our knowledge, is the first case with adult-type living fluke in the gall bladder, diagnosed by laparoscopic cholecystectomy.
Attitudes towards HIV/AIDS and other sexually transmitted diseases in secondary school students in Izmir, Turkey: changes in time
Authors: Yamazhan Tansu , Gökengin Deniz , Ertem Ekin , Sertüz Röhan , Atalay Sabri , Sertermd Demir
Published: February 2007

The aim of this study was to evaluate the changes in the sexual attitudes of young people in a period of 7 years (1997-2004). The participants in the first and the second surveys were 633 and 654 grade 10 students from six high schools located in the central district of Izmir, Turkey, chosen randomly according to the stratified sampling method. The rate of having had sexual experience was 11.3% and 22.8% in the first and second surveys, respectively ( x2 P < 0.001).
Assessment of liver hydatid cyst cases - 10 years experience inTurkey
Authors: Mergen Haluk , Genç Hüdai , Tavusbay Cengiz
Published: February 2007

We analysed 73 hydatid cyst patients according to their age, gender, localization, number of cysts, infectivity, symptoms, physical examination findings, presence of accompanying diseases, and diagnostic methods. Female/male ratio was 1.6/1. In total, 69% of cases had a single cyst and 31% multiple cysts. Of the cysts, 61% were in form of 'eau de roche' and the rest infective. The mean age was 42.3 years, ranging from 18 to 85 years. The most common symptom was abdominal pain in 74% of patients. Right lobe involvement was encountered in 65% of cases, left lobe in 13%, and left and right in 8%. In 27% of patients, cholelithiasis was the most common accompanying disease. As an imaging technique ultrasound was the most commonly used diagnostic technique.
A recent outbreak of necrotizing enteritis in eastern Sri Lanka
Authors: Mandrella Bernhard
Published: February 2007

This report details an outbreak of jejunitis necroticans seen in 42 patients in the Provincial Hospital in Batticaloa, Sri Lanka.
Challenges in HIV post-exposure prophylaxis for occupational injuries in a large teaching hospital in Malawi
Authors: van Oosterhout Joep J G , Nyirenda Mulinda , Beadsworth Michael B J , Kanyangalika Joseph K , Kumwenda Johnstone J , Zijlstra Eduard E
Published: February 2007

We describe the evaluation of the HIV post-exposure prophylaxis (PEP) programme for occupational injuries in Queen Elizabeth Central Hospital, Blantyre, Malawi. An audit was performed 1 year after introduction, by reviewing files of all clients who sought advice regarding PEP. In addition, the incidence of occupational injuries and awareness of the programme were assessed through interviews with nurses.

The logistics of the programme were adequate. Of 29 clients who reported occupational injuries,19 started PEP. Only double antiretroviral drug therapy was available; side-effects were common but generally mild. Attendance of scheduled follow-up visits was poor, and few HIV test results after completion of PEP were obtained. Interviews with nurses revealed a high incidence of occupational injuries, but many did not report for advice about PEP; mostly because of unawareness of the programme and a reluctance to be tested for HIV.
Seroprevalences and co-infections of HIV, hepatitis C virus and hepatitis B virus in injecting drug users in Quetta, Pakistan
Authors: Achakzai Malik , Kassi Masoom , Kasi Pashtoon Murtaza
Published: February 2007

A questionnaire-based survey was administered to a sample of street-recruited injecting drug users. Written informed consent was obtained. Serological screening and further testing for the three blood-borne infections was performed. Fifty (76.9%) consented for serological testing. Seroprevalences of hepatitis C virus (HCV), HIV and hepatitis B antigen were 60%, 24% and 6%, respectively. Co-infections of HCV/HIV were particularly high (20%).
The prevalence of Plasmodia parasitaemia among donors in the Niger delta of Nigeria
Authors: Erhabor Osaro , Ok Obunge , Awah Isaac , Uko Kufre Emmanuel , Charles Adias Teddy
Published: February 2007

Giemsa-stained blood films from 1018 consecutively recruited blood donors was examined quantitatively for plasmodium species to determine the prevalence of transfusion-transmissible malaria among blood donors. The overall prevalence rate was 104 (10.2%). Infection rate was highest among donors aged 10-19 years (16.7%) and was significantly higher among commercially remunerated donors (17.8%) compared with family replacement donors (4.8%) ( x2 = 45.19; P < 0.001). Pre-donation mean haemoglobin value was significantly lower among malaria-parasitized donors and commercial donors (12.3-0.30 and 12.63-0.57 g/dL) compared with non-parasitized and family replacement donors (13.5-1.01 and 13.9-0.96 g/dL) ( x2 = 143.88; P = 0.001) and ( -2 = 392.7; P = 0.001), respectively. This study confirms a high prevalence of transfusion-transmissible malaria among blood donors and lays bare the need to routinely treat transfusion recipient with anti-malaria as a prophylactic measure.
Use of protective eyewear among surgeons in a tertiary hospital in northern Nigeria
Authors: Tukur J , Yakubu A A , Sheshe A A , Abubakar I S
Published: February 2007

The study was a prospective study during which a hand-held lens was used to examine the goggles of all surgeons who used them during surgery at Aminu Kano Teaching Hospital, Kano, Nigeria.

Only 169 (54.8%) of the 308 surgeons used eye protection during surgery. There was at least a bloodstain on 70 (41.4%) of the goggles. There is need to enforce universal precautions during surgery to protect the eyes of surgeons from blood drops of the patient being operated.
Bleach-digested sputum smears for the diagnosis of TB in HIV-infected individuals
Authors: Douthwaite S , Yassin M A , Squire S B , Arbide I , Cuevas L E
Published: February 2007

We describe the performance of bleach-digested Zeihl-Neelsen (ZN) smears in TB suspects with/without HIV. In total, 51 (26%) and 62 (31%) out of the first 198 spot and digested smears were positive. Seven of the 30 HIV-positive patients had TB and their ZN smears were negative, scanty or 1 +. Six of seven digested smears were scanty. Forty-two of 115 HIV-negative patients had TB. Eleven (26%) of their digested smears were negative, 12 (29%) scanty and 19 (45%) positive. Despite the lower bacilli numbers of HIV-positive patients, the technique had sensitivity and specificity similar to that in HIV-negative patients.
Sublingual misoprostol in management of missed abortion in India
Authors: Sharma Damyanti , Singhal Savita Rani , Rani X X
Published: February 2007

This prospective study was carried out at a tertiary care hospital on 50 women with missed abortion up to 13 weeks who were given 600 μg misoprostol sublingually every 3 h for a maximum of three doses. Success rate was 86% (up to 72 h), and the acceptability of the method was 69.7%. Sublingual misoprostol is a non-invasive, effective and safe medical method for completion of abortion in missed abortion.
Induction of labour with intravaginal misoprostol and prostaglandin E2 gel: a comparative study
Authors: Nanda Smiti , Singhal Savita Rani , Papneja Akta
Published: February 2007

A prospective study was carried out at a tertiary care hospital on 100 pregnant women admitted for induction of labour to compare the effect of misoprostol and dinoprostone on the induction of labour.

The patients were divided randomly into two groups of 50 each. Group I received 25 μ;g misoprostol intravaginally every 3 h (maximum dose 200 μ);g), and Group II received 0.5 mg PGE2 gel (dinoprostonev) intracervically every 6 h (maximum three doses in 24 h) until good uterine contractions started. The primary outcome measure was vaginal delivery occurring within 24 h of administration of the first dose of either study drug (successful induction). Statistical analysis were conducted using x2 test, Fisher exact test, Student's t-test and relative risk (RR) with 95% confidence interval (CI).

In the misoprostol group, more patients achieved successful inductions as compared with the dinoprostone group, 80% vs. 62% ( P = 0.0473, RR 1.63, 95% CI 0.95-2.81). The mean induction to delivery interval (IDI) was shorter in the misoprostol group, 13.30±8.74 (3-40.15) hours, as compared with the dinoprostone group, 18.53±11.33 (2-48.07) hours ( P = 0.011). Misoprostol was associated with significantly less oxytocin use (18% vs. 50%) as compared with dinoprostone ( P = 0.001 RR 0.36, 95% CI 0.19-0.69).

In conclusion, although both misoprostol and dinoprostone appear to be effective agents for labour induction, misoprostol is cheaper, stable at room temperature, has shorter IDI and requires less oxytocin. These results make misoprostol superior to dinoprostone for induction of labour especially in developing and tropical countries.
Gastrointestinal tract perforation in neonates
Authors: Kuremu R T , Hadley G P , Wiersma R M
Published: February 2007

Gastrointestinal tract perforation in neonates is a serious problem associated with high morbidity and mortality. Co-morbid factors, particularly prematurity and low birth weight, impact negatively on the outcome. This article highlights issues related to diagnosis and treatment with a view to improving the poor prognosis found in this condition.
The safety and complications of Norplant use in Calabar
Authors: Ekabua J E , Itam I H
Published: February 2007

Four hundred and seven Norplant insertions were performed over a 2 year period, from January 1998 to December 1999. The clients were followed up over a period of 36 months ending in June 2002. The overall complication rate was 22.6%, and the cumulative continuation rate was 84.0%. Menstrual bleeding disturbances were the most common reported complication in 50 (12.3%) clients. However, there was no significant change in packed cell volume among those clients. Desire for pregnancy was the most common reason for discontinuing Norplant use in 24 (5.9%) cases. Norplant was inadvertently inserted in a client who was pregnant, 3 months after her last confinement. The implants were removed after 8 week use, and the pregnancy was carried to term. There was no fetal abnormality. Thirty-one (7.6%) clients were lost to follow-up.
Identifying the training needs of traditional birth attendants
Authors: Salako A A , Daniel O J
Published: February 2007

With the aid of pre-tested, structured, interview questionnaires, 51 traditional birth attendants (TBAs), identified by their certificate of traditional midwifery, were assessed for their knowledge about the care given in pregnancy, labour, and the postnatal period, beliefs and delivery practices including child care, and their attitude towards orthodox midwifery. A total of 22 (43.1%) so identified were found to be practicing traditional midwifery as a full-time job, while 29 (56.9%) were practising on a part-time basis, doing other jobs such as farming and trading. Twenty-two (51.2%) of the male TBAs practised traditional midwifery as a full-time job, while the remaining 21 (48.8%) practised traditional midwifery part-time, along with farming occupation. All the female TBAs practised traditional midwifery part-time with their main occupation such as trading. There was no significant difference between the mean age of male compared with female respondents (59.3±15.1 vs. 54.6±15.9 years; P = 0.43). Harmful traditional practices, practices that may need verification and areas where training is needed are highlighted. The importance of registration and active supervision of their practices were discussed. The skills that need to be stressed include identification of danger signs in pregnancy and prompt referral of maternal complications. The essence of registration for monitoring of their activities cannot be overemphasized. Findings also revealed that appropriate training could expand their roles in primary health care programmes.
HIV transmission among drug users in Larkana, Pakistan
Authors: ur Rehman Nadeem , Emmanuel Faran , Akhtar Saeed
Published: February 2007

During a routine surveillance programme, 17 of 183 drug users in Larkana, Pakistan, were found to be HIV positive. To investigate the factors to this rapid transmission of HIV, a case-control study was conducted. Cases were HIV seropositive male drug dependants, while controls were drug dependants who were tested to be HIV seronegative. A total number of seven cases and 14 controls were recruited for the investigation at a case:control ratio of 1:2. Univariate logistic regression analysis of the data showed that injection drug use in groups, re-using a syringe that is used by a companion, sex with commercial sex workers, having multiple sex partners, and early initiation of sexual activity were associated with HIV seropositivity among heroin addicts.
Physiological macrocytosis of pregnancy
Authors: Mukhopadhyay Asima , Bhatla Neerja , Kriplani Alka , Saxena Renu
Published: February 2007

In a prospective study of 40 women, mean corpuscular volume (MCV) values in second and third trimesters were compared between women who were iron deficient and those who were iron replete. There was no difference in the two groups. Hence reduced MCV seen in iron deficiency anaemia cannot be relied upon as an effective marker in pregnancy due to physiological macrocytosis.
Prevalence of blindness and its causes among those aged 50 years and above in rural Karnataka, South India
Authors: Chandrashekhar T S , Bhat H V , Pai R P , Nair S K
Published: February 2007

To estimate the prevalence of blindness and its causes among those aged 50 years and above in rural Karnataka.

A total of 1505 people aged 50 years and above from 15 villages were examined. The participants were selected through a house-to-house survey by the cluster sampling method. Visual acuity was tested using a modified Snellen's chart, and eyes were examined to ascertain the cause of blindness.

The prevalence of blindness was 6.6% (95% confidence interval: 5.3-7.8%). Bilateral cataract was the principal cause of blindness among 78.7% of the blind and 12.1% were operated for cataract. In conclusion, the study area has a high burden of cataract blindness.

Cataract surgical services should be made readily accessible and available to this rural population.
Measles epidemiology in Mazandaran province, Iran, 2000-2002
Authors: Saffar M J , Amiri-Alreza M , Baba-Mahmoodi F , Saffar H
Published: February 2007

To determine the incidence and characteristics of measles, cases reported to the Health Center for Diseases Control 2000-2002 were reviewed. Demographics data, vaccination status and its relation to occurrence the disease were analysed.

A total of 729 cases (270 women,162, 269, 298, over the 3 years) were reported. The annual incidence rates over the 3 years were 7.1, 11.9 and 12.7 for each 105 population. In full vaccinated subjects, 46.5% of the cases occurred and 39.9% of the cases had not been vaccinated.

Because of the high incidence rate of measles both in vaccinated and unvaccinated individuals, paying more attention to proper shipping and storing of vaccine, and even catch-up immunization for increasing herd immunity are recommended.
A computational proposal for designing structured RNA pools for in vitro selection of RNAs
Authors: Kim Namhee , Gan Hin Hark , Schlick Tamar
Published: February 2007

Although in vitro selection technology is a versatile experimental tool for discovering novel synthetic RNA molecules, finding complex RNA molecules is difficult because most RNAs identified from random sequence pools are simple motifs, consistent with recent computational analysis of such sequence pools. Thus, enriching in vitro selection pools with complex structures could increase the probability of discovering novel RNAs. Here we develop an approach for engineering sequence pools that links RNA sequence space regions with corresponding structural distributions via a “mixing matrix” approach combined with a graph theory analysis. We define five classes of mixing matrices motivated by covariance mutations in RNA; these constructs define nucleotide transition rates and are applied to chosen starting sequences to yield specific nonrandom pools. We examine the coverage of sequence space as a function of the mixing matrix and starting sequence via clustering analysis. We show that, in contrast to random sequences, which are associated only with a local region of sequence space, our designed pools, including a structured pool for GTP aptamers, can target specific motifs. It follows that experimental synthesis of designed pools can benefit from using optimized starting sequences, mixing matrices, and pool fractions associated with each of our constructed pools as a guide. Automation of our approach could provide practical tools for pool design applications for in vitro selection of RNAs and related problems.
Hair tourniquet syndrome in an infant
Authors: Haene R. A. , Loeffler M.
Published: February 2007

An 11-week-old infant presented with swelling and discoloration of the left second toe because of hair thread tourniquet syndrome. This was treated by urgent surgical release of the constricting band, with a successful outcome. The authors stress the importance of recognising this rare condition and of prompt, complete, surgical release.
Reconstruction with non-vascularised fibular grafts after resection of bone tumours
Authors: Krieg A. H. , Hefti F.
Published: February 2007

We evaluated 31 patients who were treated with a non-vascularised fibular graft after resection of primary musculoskeletal tumours, with a median follow-up of 5.6 years (3 to 26.7 years). Primary union was achieved in 89% (41 of 46) of the grafts in a median period of 24 weeks. All 25 grafts in 18 patients without additional chemotheraphy and/or radiotherapy achieved primary union, compared with 16 of the 21 grafts (76%; 13 patients) with additional therapy (p = 0.017). Radiographs showed an increase in diameter in 70% (59) of the grafts. There were seven fatigue fractures in six patients, but only two needed treatment.

Non-vascularised fibular transfer is a simpler, less expensive and a shorter procedure than the use of vascularised grafts and allows remodelling of the fibula at the donor site. It is a biological reconstruction with good long-term results, and a relatively low donor site complication rate of 16%.
Celecoxibversusibuprofen in the prevention of heterotopic ossification following total hip replacement
Authors: Saudan M. , Saudan P. , Perneger T. , Riand N. , Keller A. , Hoffmeyer P.
Published: February 2007

We examined whether a selective cyclooxygenase-2 (COX-2) inhibitor (celecoxib) was as effective as a non-selective inhibitor (ibuprofen) for the prevention of heterotopic ossification following total hip replacement. A total of 250 patients were randomised to receive celecoxib (200 mg b/d) or ibuprofen (400 mg t.d.s) for ten days after surgery. Anteroposterior radiographs of the pelvis were examined for heterotopic ossification three months after surgery. Of the 250 patients, 240 were available for assessment. Heterotopic ossification was more common in the ibuprofen group (none 40.7% (50), Brooker class I 46.3% (57), classes II and III 13.0% (16)) than in the celecoxib group (none 59.0% (69), Brooker class I 35.9% (42), classes II and III 5.1% (6), p = 0.002). Celecoxib was more effective than ibuprofen in preventing heterotopic bone formation after total hip replacement.
Repair of osteochondral defects with a new porous synthetic polymer scaffold
Authors: Nagura I. , Fujioka H. , Kokubu T. , Makino T. , Sumi Y. , Kurosaka M.
Published: February 2007

We developed a new porous scaffold made from a synthetic polymer, poly(DL-lactide-co-glycolide) (PLG), and evaluated its use in the repair of cartilage. Osteochondral defects made on the femoral trochlear of rabbits were treated by transplantation of the PLG scaffold, examined histologically and compared with an untreated control group.

Fibrous tissue was initially organised in an arcade array with poor cellularity at the articular surface of the scaffold. The tissue regenerated to cartilage at the articular surface. In the subchondral area, new bone formed and the scaffold was absorbed. The histological scores were significantly higher in the defects treated by the scaffold than in the control group (p < 0.05).

Our findings suggest that in an animal model the new porous PLG scaffold is effective for repairing full-thickness osteochondral defects without cultured cells and growth factors.
Posterior lumbar interbody fusion and posterior instrumentation in the surgical management of lumbar tuberculous spondylitis
Authors: Lee J. S. , Moon K. P. , Kim S. J. , Suh K. T.
Published: February 2007

There are few reports of the treatment of lumbar tuberculous spondylitis using the posterior approach. Between January 1999 and February 2004, 16 patients underwent posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation. Their mean age at surgery was 51 years (28 to 66). The mean follow-up period was 33 months (24 to 48). The clinical outcome was assessed using the Frankel neurological classification and the Kirkaldy-Willis criteria.

On the Frankel classification, one patient improved by two grades (C to E), seven by one grade, and eight showed no change. The Kirkaldy-Willis functional outcome was classified as excellent in eight patients, good in five, fair in two and poor in one. Bony union was achieved within one year in 15 patients. The mean pre-operative lordotic angle was 27.8° (9° to 45°) which improved by the final follow-up to 35.8° (28° to 48°). Post-operative complications occurred in four patients, transient root injury in two, a superficial wound infection in one and a deep wound infection in one, in whom the implant was removed.

Our results show that a posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation for tuberculous spondylitis through the posterior approach can give satisfactory results.