bluuebunny/crossref_metadata_2025 huggingface dataset:
Helmet Mounted Digital Imaging Systems: Cockpit Compatibility Implications
Authors:   Esterline Control and Communication Systems, Robinson Tim , Green John
Published: October 2024

In recent years, there has been increasing interest in replacing or augmenting analog night vision goggles (NVGs) with helmet mounted digital imaging systems. The interest is driven by certain technical advantages such as the ability to detect light from the visible to the short-wave infrared (SWIR) band, to enhance the contrast digitally, to improve situational awareness by fusing images from various sensors, to export data to remote locations for complex analysis, and to use the imaging system in day and night conditions. Digital imaging systems with SWIR spectral responsivity provide additional advantages in that they can present an image through certain conditions of smoke or fog, and are able to detect elements that exhibit higher reflectivity in the SWIR band than in the near infrared or visible band. The US Air Force Research Laboratory (AFRL) has an active program to develop a SWIR helmet mounted digital imaging system for flight operations. Integrating this advanced SWIR imaging system into a cockpit presents new human factor issues, particularly concerning compatibility with illuminated instruments. In this paper, we will discuss a compatibility model that extends existing specifications into the SWIR band. This model is the culmination of three year program sponsored by AFRL.
From EC145 to H145: Validation Program of Major Dynamic Changes
Authors:   Airbus Helicopters Deutschland, Houg Wouter , Dreher Stefan , Heger Rainer , Dieterich Oliver , Priems Martijn
Published: October 2024

In January 2014, Airbus Helicopters achieved EASA type certification of the H145. The H145 development program entails a significant upgrade from the EC145. The comprehensive changes with respect to dynamics and external acoustics required the application of an extensive validation program. This paper gives a detailed overview of this validation program; from the design stage, through certification until entry into service. A coherent and logical development methodology was applied, relying heavily on the use of numerical tools validated by using the results of laboratory, ground and flight testing. The improved acoustic footprint due to the Fenestron® tail rotor system, and the investigations with respect to aeromechanic stability margins due to the new structure and engine control laws will be presented. Additionally, the drive train dynamics as well as the new cabin active vibration control system will be discussed in detail.
The Bell 525's Smooth Ride
Authors:   Bell Helicopter, Hendricks Matt
Published: October 2024

The Bell 525 Relentless is designed to fly farther and faster than any previous Bell commercial helicopter. The increase in flight time means that vibration and internal noise are more significant elements to crew and passenger comfort. To address crew exposure to these factors, the 525 employs a three-tier strategy for reducing vibration and structure-borne acoustics. The approach first reduces the transmissibility of source vibrations from entering the airframe. Secondly, the airframe structure natural modes are desensitized from the rotor excitation frequencies. Third, remaining vibrations are treated with vibration reduction equipment. While this strategy was successfully used in the design of the Bell 429, the 525 Relentless takes this approach to the next level through lessons learned from the 429, improvements in the pylon design, and incorporating technology advancements in active vibration reduction. With first flight of the 525 Relentless in July 2015, envelope expansion through 200 knots airspeed has demonstrated the success of this three-tier strategy with vibration levels that set the standard for the industry.
Measurement and Validation of a Mach-Scale Rotor Performance and Loads at High Advance Ratios
Authors:   University of Maryland, Wang Xing , Saxena Anand , Chopra Inderjit
Published: October 2024

Reducing the rotor tip speed by slowing down the rotor in forward flight is a viable means of extending the cruise speed of a compound helicopter. However, in a high advance ratio flight regime, many aerodynamic phenomena remain unclear, including the thrust reversal and the dynamic stall that occurs in the reverse flow region of the retreating blade. In order to investigate the performance and vibratory loads characteristics of a high advance ratio rotor, wind tunnel tests were conducted with a Mach-scale 4-blade articulated rotor at 900 RPM, up to advance ratio 1.15. Hub loads, control angles, flap angles, blade structural loads and blade surface pressure data were measured from the test. The wind tunnel test data was compared with the predictions from an in-house comprehensive analysis code, UMARC. The performance data correlation was satisfactory for most cases, however it degrades with increasing advance ratio. The hub load and blade structure load showed similar trends; they were insensitive to collective for low advance ratio and increased with collective for high advance ratio. The trend was captured by the analysis, but the analysis tends to under-predict the magnitudes. The pitch cyclic predictions were accurate and could be used as trimming target for future tests. Finally, the pressure data was studied to characterize and understand the dynamic stall in the reverse flow region.
Influence of Dynamic Inflow States on Coupled Rotor Fuselage Modes
Authors:   IIT Madras, Nair Salini ,   Florida Atlantic University, Gaonkar Gopal , Mohan Ranjith
Published: October 2024

Dynamic inflow effects on stability and modes of a coupled rotor-fuselage system are investigated. Dynamic inflow effects are incorporated using Peters-He model. Characteristics of different modes associated with a coupled rotor-fuselage system are investigated. In addition to the magnitude of the states in the eigenvector (periodic eigenvector in general), phases of the states are also used to characterize the modes. From this approach, the effect of wake on different modes is demonstrated for two earlier tested configurations under ground-contact conditions. The ambiguity in naming a mode (due to participation of different states) is resolved from the relative phases of the relevant states.
Adverse Aeroelastic Roll/Lateral Rotorcraft-Pilot Couplings Analysis
Authors:   Politecnico di Milano, Masarati Pierangelo ,   ENSAM - France, Tod Georges ,   TU Delft, Pavel Marilena , Muscarello Vincenzo , Quaranta Giuseppe , Malburet François
Published: October 2024

The paper investigates the basic mechanism of aeroservoelastic Pilot Assisted Oscillation phenomenon (PAO) about the roll axis due to the interaction with the pilot's arm biomechanics. The motivation stems from the observation that a rotor imbalance may occur as a consequence of rotor cyclic lead-lag modes excitation. The instability mechanism is analogous to the 'air resonance' phenomenon, in which the pilot's involuntary action plays the role of the AFCS. Using robust stability analysis, the paper demonstrates that, in particular, the introduction of a gain and a time-delay between the stick motion and the servoactuator displacements may reduce the gain and phase margins of the pilotvehicle system. The mechanism of instability proves that the pilot biodynamics is participating to the destabilization of the system by inputting energy directly into the flapping mode. This destabilizes the airframe roll motion which, in turn, causes lag motion imbalance. It is found that, depending on the value of the time delay involved in the lateral cyclic control, the body couples with rotor motion in a different way. In the presence of small or no time delays, body roll couples with the rotor through the lag degrees of freedom. The increase of the time delay to 140ms modifies this coupling: the body no longer couples with the rotor through lag but directly through flap motion.
Ground Resonance Mitigation of Rotorcraft with Articulated Robotic Landing Gear: A Preliminary Investigation
Authors:   Georgia Institute of Technology, Langley Jared , Costello Mark
Published: October 2024

Ground resonance is a serious aeromechanical instability in helicopters that results from hub motion coupling with lag motion of the rotor blades when the vehicle is in contact with a surface. Nearly all recent methods to mitigate ground resonance instability rely on a passive or semi-active lag damper. These lag dampers, however, are generally undesirable for rotorcraft design and maintenance. Current innovations in rotorcraft landing gear have created an alternative approach to ground resonance mitigation. Recent work has demonstrated the capabilities of an articulated landing gear system as a feasible device for navigating irregular terrain. Adding articulated robotic landing gear to a rotorcraft can possess an additional function as a device for stability augmentation and act as a unique, built-in alternative to lag dampers. The current work presents a linear ground resonance analysis of a fully articulated rotor for a variety of helicopter characteristics. Rotor conditions that induce instability are identified and it is demonstrated that a legged robotic landing gear system can actively mitigate ground resonance.
Optimal Active Twist Deployment Schedule of a Rotor for Performance Improvement and Vibration Reduction
Authors:   Konkuk University, You Young , Jung Sung
Published: October 2024

In this paper, the best actuation schedules exploiting various waveform types are sought taking advantage of the global search algorithm for the reduction of the power required and/or hub vibration of a rotor in high speed forward flight. The active twist schedules include two non-harmonic inputs formed based on segmented step functions along with the simple harmonic waveform input. An advanced particle swarm assisted genetic algorithm (PSGA) is employed for the optimizer. A rotorcraft computational structural dynamics (CSD) code CAMRAD II is used to perform the rotor aeromechanics analysis. A CFD/CSD coupling is introduced to assist the observations made using the CSD analysis. The PSGA optimization results are verified against the parameter sweep study performed by the harmonic actuation. The best optimum twist schedules according to the performance or vibration reduction strategy are identified and their optimization gains are compared between the actuation cases. A two-phase non-harmonic actuation schedule demonstrates the best outcome in decreasing the rotor power required while a four-phase non-harmonic schedule leads to the best vibration reduction. The mechanism of reduction gains is identified illustrating the section airloads, angle-of-attack distribution, and net elastic twist deformation predicted using CSD and CFD/CSD approaches.
Investigation of Performance, Loads, and Vibration of a Coaxial Helicopter in High-Speed Flight
Authors:   Rensselaer Polytechninc Institute, Jacobellis George , Gandhi Farhan
Published: October 2024

A lift-offset coaxial helicopter is simulated using the Rotorcraft Comprehensive Analysis System (RCAS) at a speed of 230 kts. The XH-59 Advancing Blade Concept demonstrator aircraft is used for the simulation model. A variety of trim states are explored by varying vehicle pitch attitude and redundant controls, such as main rotor speed and differential lateral pitch. The performance, vibrations, and blade loads are compared for different trim states, notably, those states utilizing negative rotor power to drive the propulsor and states in which the rotor power is constrained to be non-negative. The optimal trim state for a system with a powered or free spinning rotor lies at about 3° pitch attitude, while the optimal trim state for a vehicle in which the rotor can extract power and direct it to the propulsor lies at 6-7° pitch attitude. With the aircraft operating at a high pitch attitude, the horizontal tail is able to provide a significant amount of the necessary aircraft lift, while the rotor can provide the longitudinal moment necessary for trim. The Blade loads and hub vibrations for the negative rotor power state are similar or less than for the marginally powered state.
Flutter Assessment of a Rotor Blade with Innovative Layout in Hover using Indicial Aerodynamics
Authors:   DLR - German Aerospace Center, Arnold Jürgen
Published: October 2024

The double-swept ERATO blade layout is assessed for flutter stability in hover flight and compared to the straight 7AD reference blade. Used numerical methods comprise multibody dynamics together with an unsteady aerodynamic model based on Wagner's function and related enhancements for the general motion of an airfoil section considering heave and pitch motion. The numerical solutions for flutter onset are gained from simulations in both, frequency and time domain. According flutter results are compared and observed aeroelastic couplings of the rotor blades are discussed. The two layouts exhibit the classical bending-torsion coupling as known for articulated rotor blades. An additional coupling is found with the ERATO blade. A dominant flutter mode develops with rotor harmonics of 3/rev for increasing rotor speed. The observed mechanism is composed of two flap bending modes that carry shares in blade twist as a result of the double-swept rotor blade shape.
Disturbance Rejection Handling Qualities Criteria for Rotorcraft
Authors:   US Army Aviation Development Directorate, Berger Tom ,   The Boeing Company, Miller David , Ivler Christina , Berrios Marcos , Tischler Mark
Published: October 2024

Aeronautical Design Standard ADS-33E-PRF is lacking in a viable hover/low-speed, short-term disturbance rejection criteria to design and analyze hold modes. The Disturbance Rejection Bandwidth and Peak criteria were developed to fill this gap, have been successfully used for design and analysis on many programs, and will be incorporated in the next revision of ADS-33 (revision F). This paper documents the development of these disturbance rejection criteria, from their theoretical background, to examples of their correlation with the rejection of physical disturbances, to the selection of the DRB boundaries for different hold modes. Simple, single-axis examples are used where appropriate to clearly demonstrate basic concepts. In addition, flight data, including assigned Handling Qualities Ratings, from a variety of sources are used to motivate the location of the DRB boundary values.
Adaptive Vehicle Management Systems Program Phase II Overview
Authors:   The Boeing Company, Enns Russell ,   Aviation Development Directorate, Segner David , Dryfoos James
Published: October 2024

This paper presents the results of the three and a half year Adaptive Vehicle Management System (AVMS) Phase II program, which developed a suite of technologies designed to exploit the large amount of information available across the subsystems of a modern rotorcraft and flight tested them on three platforms, an H-6 flying technology demonstrator, an H-47 Chinook and an AH-64 Apache. Technologies developed included those in the areas of tactile-cueing based carefree maneuvering, tactile cueing for maneuver and mission aiding, active external load stabilization, rotor state sensing, and alternative redundancy methods. The AVMS program expands on most other flight controls research by demonstrating a VMS that can simultaneously optimize multiple metrics including not only handling qualities but also aircraft performance, mission productivity, safety, and operating and sustainment (O&S) costs. The flight test results show benefits to mission productivity as demonstrated by an average of 19% improvement in the time to complete a range of mission task elements, along with a 34% improvement in workload, significant improvement in performance, and almost a 1 Cooper-Harper Point Rating (CHPR) improvement in handling qualities. In addition, the AVMS technologies were shown to prevent inadvertent exceedances of operating and safety limits, thereby saving a projected average of $50,000 per aircraft per year for a typical advanced capability military rotorcraft. The results substantiate our hypothesis that these technologies will make a significant positive impact on the effective and efficient operation of modern rotorcraft.
AW189 Engine Off Landing Certification by Simulation
Authors:   Finmeccanica Helicopter Division, Bianco-Mengotti Riccardo , Ragazzi Andrea , Grande Federico , Cito Gianfranco , Zappellini Alessandro
Published: October 2024

This paper presents the certification by piloted simulation of the Engine Off Landing manoeuver for the AW189 helicopter, i.e. the use of the mathematical model and the flight mechanics simulator laboratory with pilot in the loop in order to develop and demonstrate to the Certification Authority the capability of the helicopter to perform a safe landing after the failure of all the engines without requiring exceptional piloting skills, within the helicopter structural design and operative boundaries.
High Order Compensator Augmentation of a Baseline Partial Authority Controller for Rotorcraft
Authors:   The Pennsylvania State University, Spires James , Horn Joseph
Published: October 2024

An architecture and design methodology for high order compensator (HOC) augmentation of a baseline controller for rotorcraft is presented. With this architecture, the HOC compensator is selectable and can easily be authority-limited, which might ease certification. Also, the plant for this augmentative MIMO compensator design is a stabilized helicopter system, so good flight test data could be safely gathered for more accurate plant identification. The design methodology is carried out twice on an example helicopter model, once with turbulence rejection as the objective, and once with the additional objective of closely following pilot commands. The turbulence rejection HOC is feedback only (HOC_FB), while the combined objective HOC has both feedback and feedforward elements (HOC_FBFF). The HOC_FB was found to be better at improving turbulence rejection but generally degrades the following of pilot commands. The HOC_FBFF improves turbulence rejection relative to the Baseline controller, but not by as much as HOC_FB. However, HOC_FBFF also generally improves the following of pilot commands.
Design Refinement and Flight Test of the AVMS Active External Load Stabilization System
Authors:   The Boeing Company, Bellandi Erik ,   Aviation Development Directorate, Ivler Christina , Bourreza Alex , Brewer Roy , Enns Russell , Hehr Roger
Published: October 2024

As part of the Adaptive Vehicle Management Systems (AVMS) Phase II program, an Active External Load Stabilization (AELS) system was designed that consists of Flight Control Load Stabilization (FCLS) and Active Cargo Hook (ACH) methods to stabilize a load which can also be combined and operated simultaneously. Prior flight testing revealed issues with the performance of the AELS system that were a result of a modeling error as well as the need to utilize different underlying flight control system control law feedback gains when flying with an external load. Fixing the modeling error had a significant impact on the evaluation of the system in piloted simulation, particularly for the FCLS method. A more comprehensive control law gain optimization was employed using CONDUIT® in order to achieve all of the desired design requirements, such as stability margins, handling qualities (HQ), and load-damping (LD). Changes were also made to the mode switching between the FCLS-HQ and FCLS-LD modes. Following these updates, the system was re-evaluated in piloted simulations and flight test. The results show that the ACH and FCLS systems each performed extremely well; significantly reducing load motion and allowing the pilot to more quickly complete tasks with an external load. The combined ACH+FCLS system performed very well, however even better performance is expected with further refinements.
Carefree Maneuvering via Tactile Cueing Flight Demonstrations
Authors:   The Boeing Company, Kashawlic Bryan , Enns Russell , Irwin Joseph , Moore Rucie
Published: October 2024

A comprehensive carefree maneuvering system with tactile cueing was developed and applied to three different demonstration aircraft: an H-6, AH-64E, and MH-47G. Common algorithms were used for all three aircraft despite the large disparity in size and flight control system configuration between the vehicles, showing the versatility and robustness of the limit prediction methodology. This paper describes the carefree maneuvering algorithms and presents results from piloted simulation and flight testing. Benefits were quantified using metrics in the categories of mission productivity, handing qualities, workload, performance, and safety and the results showed significant improvements in all areas. Based on these results, similar benefits should be expected if these carefree maneuvering tactile cues were to be integrated in any other rotorcraft platform, whether it be a legacy or future design, partial authority or fly-by-wire.
L1-based Model Following Control of an Identified Helicopter Model in Hover
Authors:   Max Plank Institute for Biological Cybernetics, Picardi Giacomo ,   University of Pisa, Pollini Lorenzo , Geluardi Stefano , Olivari Mario , Buelthoff Heinrich , Innocenti Mario
Published: October 2024

The aim of this study is to augment the uncertain dynamics of the helicopter in order to resemble the dynamics of a new kind of vehicle, the so called Personal Aerial Vehicle. To achieve this goal a two step procedure is proposed. First, the helicopter model dynamics is augmented with a PID-based dynamic controller. Such controller implements a model following on the nominal helicopter model without uncertainties. Then, anL1 adaptive controller is designed to restore the nominal responses of the augmented helicopter when variations in the identified parameters are considered. The performance of the adaptive controller is evaluated via Montecarlo simulations. The results show that the application of the adaptive controller to the augmented helicopter dynamics can significantly reduce the effects of uncertainty due to the identification of the helicopter model. For implementation reasons the adaptive controller was applied to a subset of the outputs of the system. However, the under actuation typical of helicopters makes the tracking of the nominal responses good also on the not directly adapted outputs.
Boundary Layer Transition Characteristics of a Full-Scale Helicopter Rotor in Hover
Authors:   German Aerospace Center (DLR), Richter Kai ,   Airbus Helicopters Deutschland GmbH, Klein Alexander , Schülein Erich , Ewers Benjamin , Raddatz Jochen
Published: October 2024

The boundary layer transition characteristics on both sides of a BK117-type full-scale helicopter main rotor were measured in hover conditions in a whirl tower experiment for various pitch angles. Accompanying state-of-the-art FLOWer simulations of a rigid isolated rotor with transition prediction based on empirical criteria were conducted for comparison with the measurements. The results reveal a slow upstream transition movement in the radial direction on the upper side of the blade, and a general upstream shift of the transition with increasing pitch angle. On the lower side, fully laminar flow exists in the inner part of the blade and a strong transition movement to the leading edge occurs outboard, which is shifted further outboard with increasing pitch angle. The predicted transition characteristics show qualitative agreement with the measured data on both sides of the rotor blade but quantitative differences occur.
Experimental Investigation of Fan-In-Wing
Authors:   Naval Surface Warfare Center Carderock Division, Sydney Anish , Bi Naipei , Kimmel Kevin , Haas David
Published: October 2024

Fan-in-Wing (FIW) and other embedded fan configurations have the potential to enhance the performance of future vertical take-off and landing aircraft by achieving efficient hover and high-speed forward flight. However, there is a continuing need for research to characterize the fundamental aerodynamics associated with these types of embedded fan systems. To this end, the present work experimentally investigates the aerodynamic performance of a series of generic FIW configurations in the Naval Surface Warfare Center Carderock Division (NSWCCD) 8- by 10-ft Subsonic Wind Tunnel. The goals are to understand how the aerodynamic performance of a FIW in hover is affected by different fan design parameters and also to create a benchmark dataset for model validation. The research is conducted in three phases; isolated fans in hover, FIW configurations in hover, and FIW configurations in transition from hover to forward flight. This paper describes the experimental approach and results obtained from the second phase of testing, which examines a number of different generic FIW configurations. Particular focus is placed on examining the effects of fan rotational frequency, blade pitch angle, number of blades, fan solidity, blade twist, and fan axial position within the wing duct. Furthermore, to better quantify the aerodynamic performance of the fan and the wing as well as the interactions within FIW systems, the model is designed such that the fan performance can be measured independently of the total FIW system performance. The results show that the fan and the wing form a complex and coupled aerodynamic environment that can, at times, be counter-intuitive when compared to results expected from an isolated fan. In general, the results suggest that all of the design variables affect the inflow distribution on the blades and, therefore, the overall aerodynamic performance as well as the stall characteristics of the fan and total FIW system. It is also clear that the future FIW systems must consider an integrated design philosophy that treats the fan and the wing as a coupled aerodynamic system. These results, along with those obtained in Phase I, will ultimately be used as a baseline for comparison with results in Phase III of the study which will examine the generic FIW configuration in transition and forward flight.
Reviewing equitable justice and the land question in South Africa from a reformation perspective
Authors: Muswubi Takalani A.
Published: October 2024

This article reviews equitable justice and the land question in South Africa from a reformation perspective. Land as the source of individual and corporate group identity and livelihood is one of the most sensitive, contentious and controversial of all debatable issues in South Africa. As such, the question is: what counts as the criteria for an amicable and lasting solution for the land question? What type of justice helpful in correcting the past injustice? An underlying precept is on restoring the broken relationship between the victims and offenders using equitable Justice, as we live together in a diverse context in South Africa. This article is designed to examine three aspects related to fair justice from the perspective of reformation: firstly, the basic conception of equitable justice; secondly, the critical application of the types of justice in handling land questions in South Africa; and thirdly, the ultimate reception of the equitable justice that the victims and offenders could acknowledge and appreciate about the land question based on the 1996 South African Constitution.Contribution: This article is meant to add value not only to how justice was and is conceived (perceived) but what is critical is the application of the types of justice as far as land in South Africa is concerned and the underlying misconceptions that go with it. Above all, the ultimate reception of the United Nations Declaration of Human Rights and the South African Constitution as an incentive to address land questions in the South African context.
The game of Cops and Robber on geodesic spaces
Authors: Mohar Bojan
Published: October 2024

The game of Cops and Robber is traditionally played on a finite graph. The purpose of this article is to introduce and analyze the game that is played on an arbitrary geodesic space (a compact, path-connected space endowed with intrinsic metric). It is shown that the game played on metric graphs is essentially the same as the discrete game played on abstract graphs and that for every compact geodesic surface there is an integercsuch thatccops can win the game against one robber, andconly depends on the genusgof the surface. It is shown that$c=3$for orientable surfaces of genus$0$or$1$and nonorientable surfaces of crosscap number$1$or$2$(with any number of boundary components) and that$c=O(g)$and that$c=\Omega (\sqrt {g})$when the genusgis larger. The main motivation for discussing this game is to view the cop number (the minimum number of cops needed to catch the robber) as a new geometric invariant describing how complex is the geodesic space.
Assessment of Physico-Chemical Parameters of River Sabon Dagah, Minna, Niger State
Authors: R. J Kolo , O. J Babalola , V. S Amesa , N. O Adeniyi
Published: October 2024

The study on the assessment of the physico-chemical parameters of Sabon Dagah River Minna, Niger State, was carried out from May to September, 2019 with the aim of determining the physical and chemical parameters of Sabon Dagah River and also to identify the fish that may be present in the river. Four sampling stations were selected, namely: Upstream (Station 1), before the bridge (Station 2), after the bridge (Station 3) and downstream (Station 4). The physico-chemical parameters were determined using standard methods, procedures and techniques. The results obtained showed the results of the measured parameters water tempe- rature (26.35±0.20°C to 28.33±0.08°C), pH (6.52±0.05 to 9.08±0.10), conductivity (118.0±1.32μs/ cm to 195.75±0.76 μs/cm), total alkalinity (3.65±0.25 mg/L to 25.5±0.42 mg/L), total hardness (64.5±1.18 mg/L to 34.9±2.31 mg/L), chloride (8.32±0.28 mg/L to 11.21±0.32 mg/L), calcium (6.30±0.75 mg/L to 22.15±0.65 mg/L), CO2 (0.75±0.04 mg/L to 3.41±0.31 mg/L), total dissolved solids (51.84±1.18 mg/L to 125.28±0.46). The assessment of River Sabon Dagah's water quality revealed variations among sampling stations and months. While some parameters met WHO standards, others, like dissolved oxygen and biological oxygen demand, indicated potential pollution sources such as agricultural runoff and industrial discharges. Conservation efforts and pollution control measures are vital to safeguard the river's health and freshwater resources in the region.
Impact of Occupational Exposure on Bacterial Community Dynamics in Selected Niches of Human Dermal Ecosystem
Authors: O. D Umoren , O.O Osifeso , A.A Durojaiye , M.B Oke , A.O Adedire
Published: October 2024

The impact of occupational exposure on bacterial community dynamics in selected ecologicalniches of the human dermal ecosystem was examined. Samples were collected from threeskin niches (palms, forearms and feet) of volunteers for different occupations (automobilemechanics, civil servants, food vendors, traffic officers, masons and welders) to make acomposite and examined using standard microbiological methods. Results showed that 46.7%of the bacteria abundance was from the palms, 28.7% from feet and 24.6% from forearms.Based on occupation type, the highest bacterial abundance was isolated from Mason (23.5%)while the lowest was recorded in Civil servants (11.4%). Based on occupational exposure byniches, palms have the highest bacterial abundance from Masons (26.8%) while the lowestwas from Auto-mechanics (9.4%). Forearms have the highest from Masons (20.9%) while thelowest was from civil servants (6.0%). Feet have the highest from Masons (20.5%) while thelowest was from Civil servants (10.3%). Eight (08) bacterial species (Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus viridans, Citrobacter spp., Escherichia coli and Proteus mirabilis) were isolated from the palms, Five (05) (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus and Pseudomonas aeruginosa) from the fore arms while Seven (07) species (Corynebacterium spp., Propiniobacterium granulosum, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Proteus mirabilis and Pseudomonas aeruginosa) from the feet. B. subtilis, S. aureus, S. epidermidis were common to all niches. Occupational exposure can cause dermal bacterial community dynamics which could be of potential dermatological importance.
Evaluating the Serum Electrolyte Status of Preeclampsia Women Cared for in Tertiary Hospitals in Enugu Metropolis: A Cross Sectional Study
Authors: H. O Obianyido, , O. E Obianyido, , C. R Onwasigwe-Obiatuegwu , O. C Nwachukwu, , O. O Okafor
Published: October 2024

Preeclampsia is a pregnancy-specific multisystem disorder that typically begins at 20 weeks or later in pregnancy and occurs in 3-5% of pregnancies. This becomes necessary to evaluate the serum electrolyte status of preeclampsia women cared for in tertiary hospitals in Enugu metropolis. The study was conducted in University of Nigeria teaching hospital Enugu and Enugu State University of Science and technology teaching hospital all in Enugu metropolis. A cross sectional survey design was conducted on pregnant women from August to December 2023. Sociodemographic data was obtained from sixty pregnant women (thirty preeclampsia and thirty normotensives) within the age of 18-45 years. Five milliliters of venous blood sample was collected from the study participants for the analysis of serum level of electrolytes (sodium, potassium, chloride and bicarbonate). Anthropometric measurements were done using standard procedures. The statistical package, graph pad prism version 7 was used to analyze data generated from this study. There was a notable increase (p>0.05) was observed in the systolic (186.30±6.00) and diastolic(114.50±3.50) blood pressure, and potassium level(4.53±0.06) of the preeclampsia study participants in comparison to the systolic (106.2±1.90), diastolic (67.67±2.30) blood pressure, and potassium levels( 4.13±0.05) normotensives. A noteworthy decrease (p<0.05) was observed in the sodium level (129.80±0.55) of the preeclampsia women in comparison to the normotensives (133.2±0.76). No significant difference (p>0.05) was observed in the serum levels of chloride and bicarbonate. This study demonstrated a notable decreased (p<0.05) inserum sodium and an increase in potassium levels in preeclampsia pregnant women in comparison to the normoten-sives. A well designed study regarding the impact of preeclamp-sia on the ion channels particularly Na+/K+ cotransporter is recommended.
Impact on Growth and Nutrient Utilization on Health and Hematological Effects of Cassia tora (L) on Clarias gariepinus (Burchell, 1882)
Authors: M.M Abubakar , A. Kamal , I. M Suleiman , A.S Hassan
Published: October 2024

The African catfish (Clarias gariepinus) is the most cultivated species with desirable characteristics. The hematological parameters change in C. gariepinus fed varying inclusion of Cassia tora (leaf and seeds) meals. The aim of this study was to determine the impact on growth and nutrient utilization on health and hematological effects of Cassia tora (L) on Clarias gariepinus (Burchell, 1882). C. tora leaves and seeds were washed, shed dried, and ground with mortar and pestle into powder. The ingredients were ground into powder, weighed, and mixed thoroughly with the addition of warm water to make a dough and pellet using form pellet. Clarias gariepinus juveniles were acclimatized to experimental conditions for 7 days prior to the feeding trials. A group of catfish with an average body weight of 4.3 g and standard length of 6.41 cm were stocked in 15 aquariums comprising 20L capacity circular tanks. The results showed that there is a significant difference in RBC, with the seed meal having the highest values. There were no significant differences in WBC. The PCV was within the minimum required standard; there was significance in MCH, MCV, HB, and MCHC. The highest values of HB and MCHC were obtained in Clarias gariepinus fed leaf and seed meals. However, there was mild stress placed on the health of the catfish even when fed at high percentage levels of inclusion (100%). Therefore, the inclusion level of (25%) of C. tora (leaf and seed meals) wasrecommended in the feed formulation using C. tora.
Larvicidal effect of Azadirachta indica, Moringa oleifera, and Carica papaya on the development of Anopheles gambiae (Diptera: Culicidae) larvae
Authors: D. A Bassey , A. I Nta , E. E Imalele , H. C Nku , I. F Etim , V. M Udofia , U. S Inyang
Published: October 2024

A wide range of pyrethroid and organochlorine resistance has been observed across most African countries. Therefore, using eco-friendly plant botanicals to control Anopheles larvae offers a cost-effective alternative method for larval management. This study assessed the larvicidal effect of Azadirachta indica, Moringa oleifera, and Carica papaya on the growth of Anopheles gambiae larvae (Diptera: Culicidae). Azadirachta indica, M. oleifera, and C. papaya leaves were obtained, processed and crushed into powder using a Qasa electric grinder. Anopheles larvae were collected from natural breeding sites using dippers and nets. Twenty live larvae were subjected to test cups filled with 100 ml of distilled water containing A. indica, M. oleifera, and C. papaya leaf powder at concentrations of 0.001, 0.005, and 0.01 g/ml. The larvae were exposed to these treatments for 24 and 48 hours, respectively, with four replicates for each concentration. The Anopheles larvae showed 100% mortality within 24 hours when exposed to 0.01 g/ml of C. papaya. Similarly, 0.01 g/ml of M. oleifera resulted in mortality rates of 45% at 24 hours and 100% at 48 hours. In contrast, A. indica leaf powder showed the least effectiveness, with mortality rates of 2.5% and 30% observed after 24 and 48 hours of exposure. A strong positive linear relationship was observed between the concentration of A. indica (r² = 0.83), M. oleifera (r² = 0.66), and Anopheles larvae mortality. Carica papaya exhibited superior larvicidal efficacy with higher mosquito mortality and a lower LC50 value. The mortality of Anopheles larvae exposed to A. indica and M. oleifera depended on concentration and duration. A. indica, M. oleifera, and C. papaya leaf powder can minimize and compliment measures towards control and inhibit development of Anopheles larvae.
Isolation and Characterization of Antibiotic Producing Actinomycetes from Soils of Hawassa, Southern Ethiopia
Authors: Alazar Ergena Keshamo  , Abayneh Agena  , Zufan Bedewi
Published: October 2024

Antimicrobial resistance has increased drastically in recent years in the developing countries, and it is a leading public health concern. With almost all organisms becoming multidrugresistant to the commonly used antibiotics, there is a need to search for more drugs that are novel in order to address this challenge.Actinomycetes are considered as one of the most diverse groups of filamentous bacteria capable of thriving into different types of ecological niches due to their bioactive potential. Therefore, this study was aimed at the isolation and characterization of Actinomycetes from 20 soil samples that were collected from different subcities of Hawassa city, Southern Ethiopia. The Actinomycetes were isolated using serial dilution followed by spread plate techniques and antimicrobial activity screening done using modified agar disc diffusion method. Actinomycete Isolation Agar (AIA) was used to isolate Actinomycetes. A total of twenty nine different Actinomycetes,identified as AB1-AB29, were isolated.They were differentiated based on the difference in appearance of the colonymorphology and mycelial structure. Their metabolites were tested for antibiotic activities through the primary screening using modified agar disk diffusion methods. Test bacteria were E. coli, Klebsiella pneumoniae, Staphylococcus aureus, Shigella boydii and Salmonella typhi. Actinoycete isolates with broad spectrum activity were further tested against Methicillin-resistant Staphylococcus aureus (MRSA) using modified agar disk diffusion methods. Out of 29 isolates, 19 (65.5%) actinomycetes showed antimicrobial activity against selected bacterial pathogens.Most of the isolates (84.2%) showed good antimicrobial activity against Salmonella typhi though significantly lower than the control drug Ciprofloxacin.Maximum zone of inhibition was 29.2 mm observed against S.typhi. As the result indicates, the Actinomycetes isolates showed higher inhibition zone against Gram negative bacteria than Gram-positive bacteria.The study indicated that soils of Hawassa may have potential group of actinomycetes with broad spectrum antimicrobial activity. It is therefore suggested that a combination of several molecular analysis methods such as DNA re-association and PCR-based fingerprinting techniques may extremely help to provide broader information about the total genetic diversity of soil Actinomycetes obtained in this study.
Preliminary results of sentinel lymph node biopsy using blue dye for early breast cancer staging: A single-centre experience in Addis Ababa, Ethiopia
Authors: Getu Bekele Philimon , Saha Sukmal , Thomas Malore Efeson , Girma Mamo Michael , Demelash Gizachew Soliyana , Jemberu Robele Taye , Bizuneh Mikru Filagot , Mitiku Alemu Tadesse , Mohammed Nigusse Ahmed , Bizuneh Abel Asfaw , Gebregziabher Hermela Addis
Published: October 2024

Background: Sentinel lymph node biopsy (SLNB) is the currently accepted standard of care for axillary staging in breast cancer (BRCa). The practice of SLNB in BRCa is limited in Ethiopia and the Eastern part of Africa. This study aimed to review a single institution's experience in Ethiopia on its practice regarding SLNB using only Methylene blue dye.
Method: A retrospective review was done on all patients diagnosed with invasive BRCa and who had undergone SLNB from October 1, 2020, to October 30, 2023. SLNB was performed using only Methylene blue dye with intradermal, sub-areolar, and peri-tumoral injections. SLNs were ultra-staged by multi-level sectioning; the remaining specimens were examined by conventional methods. The success rate and outcomes of the procedure were analyzed.
Results: Twenty female BRCa patients with clinically unremarkable axillae had Sentinel lymph node mapping (SLNM). ALND was performed on all patients. The median age was 47.75 years ± 13.33. The procedure's success rate was 100%, identifying 1 to 6 SLNs and an average of 13.6 total LNs. Pathologic evaluation revealed metastases in 6 patients (30%). Three of these patients (50%) had metastasis only to SLNs. The other three patients (50%) also had metastasis to non-SLNs. There was no skip metastasis.
Conclusion: The use of blue dye alone in SLNB in our institution was successful. SLNB didn’t eliminate the need for ALND due to the scarcity of frozen section technology and radiation therapy. Although the number of patients included would not enable us to make a statistically significant conclusion requiring collecting further data, our study showed that SLNB could accurately identify LN metastasis that might have been missed with a conventional examination of ALNs. This suggests that multiple sectioning of SLNs is extremely valuable to determining axillary metastasis, directly impacting subsequent management in resource-limited setups.
Giant schwannoma of the median nerve in a 13-year-old girl managed at a tertiary hospital in Calabar, Nigeria
Authors: Asuquo Joseph E. , Nkanga Elizabeth D. , Asuquo Best J. , Obanife Henry , Iwasam Joshua E. , Omotoso Ayodele
Published: October 2024

Schwannomas, also known as neurilemmomas, are rare benign tumours of the peripheral nerve sheath. It commonly affects adults. We reviewed the patient’s medical records, clinical examination findings, and investigation results with a literature review. We present a 13-year-old child with a history of a slow-growing, painless tumour on the volar surface of the right forearm. There was a preceding history of trauma from corporal punishment in school, which was a red herring, with no symptoms or signs of nerve deficit, but there were signs suggestive of compressive effects. We did not carry out magnetic image resonance or electrophysiological studies. We made a diagnosis of intraneural lipoma and surgically enucleated the tumour. A histopathological diagnosis of schwannoma was made. There was no residual nerve deficit post-surgery, and compressive symptoms resolved. Schannomas of the median nerve are a rare finding in a child. Surgical enucleation with nerve preservation is the treatment of choice.
WALANT (wide-awake local anaesthesia no tourniquet) and the East African surgical burden: A replicable training workshop in Eldoret, Kenya
Authors: Jani Pankaj , Park Nigel
Published: October 2024

Wide Awake Local Anesthesia No Tourniquet is a cost-effective anesthetic alternative that holds the potential to increase access to affordable and effective surgery. This surgical innovation was popularized by American hand surgeons who performed procedures successfully in less time, using less resources, with low infection rates and pain self-reports, which has since been validated with follow-up studies (4; 7; 15). This manuscript documents the impact of WALANT and presents a framework for educating health professionals on the innovation by reviewing the methods of a surgical workshop held in Eldoret, Kenya. It finally encourages the dissemination of WALANT training, since the technique has presented itself as a helpful tool in the efforts to improve access to safe and affordable surgery in East Africa.
An Assessment of Progress and Challenges in the Implementation of the National Surgical, Obstetric, and Anesthesia Plan (NSOAP) in Tanzania
Authors: Hellar Augustino M , Akoko Larry , Jumbam Desmond T. , Damian Caroline , Kapologwe Ntuli , Kengia James T. , Maongezi Sarah , Masuma Janeth , Giiti Geofrey , Lugazia Edwin , Segirinya Hannington , Pembe Andrea B
Published: October 2024

Introduction
There are significant disparities in access to safe and affordable surgery, particularly in LMICs. National Surgical Obstetric and Anesthesia Plans (NSOAPs) emerged as crucial national policy frameworks to address this gap. Although some Sub-Saharan African countries have developed and launched NSOAPs, there is limited information on evaluation of the progress and effectiveness of these plans. This study aimed to assess progress and challenges in implementing Tanzania’s NSOAP.
Methodology
We sent an electronic survey to all 26 Regional Health Management Teams (RHMTs) in mainland Tanzania to record their insights and understanding of the NSOAP and the state of Surgical Obstetric and Anesthesia (SOA). The RHMTs are key stakeholders in the NSOAP implementation as they oversee day-to-day implementation of all health interventions at the regional level.
Results
Only 4% of the surveyed RHMTs reported participating in the NSOAP development process, and 58% were unaware of the policy. The WHO Surgical Safety Checklist was rarely used, and surgical outreach programs were non-existent. There were gaps in the availability of SOA equipment and lack of radiological, intensive care and biomedical services. SOA specialists were few (1.96 specialists per 100,000 population). Most regions were excluded during the NSOAP dissemination meetings with no dedicated NSOAP coordinators at the regional level.
Conclusion
The NSOAP implementation faced various challenges in service delivery, infrastructure, equipment, human resources, information management and governance. Although slow progress has been made, there is a need for concerted efforts to achieve the NSOAP objectives. Future research should focus on comprehensive NSOAP evaluation and the establishment of an effective monitoring and evaluation framework.