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Diabetic foot complications remain a major cause of disability in diabetes and represent a severe consequence of poor glycaemic control, primarily driven by peripheral arterial obstruction, neuropathic damage, and compromised tissue perfusion. Photo-plethysmography (PPG) signals offer a non-invasive means of assessing vascular health. The objective is to provide insights that aid in tailoring interventions for subjects with diabetes. The study examines posture-related changes on PPG parameters at the posterior tibial artery in healthy subjects (Group A) and subjects with diabetes (Group B). Physiological parameters analysed included pulse amplitude, mean Peak-to-Peak-Interval (PPI), SDPP, Low-Frequency to High-Frequency ratio (LF/HF), b/a ratio, and (b-c-d-e)/a ratio. Postural effects were evaluated in 30 subjects per group using two-way ANOVA and Mann–Whitney U tests. Morphological analysis of PPG waveforms in Group B revealed a gradual systolic rise, prolonged diastolic decay, and a less prominent dicrotic notch, indicating accelerated vascular aging. Significant main effects of posture were found for pulse amplitude, mean PPI, SDPP, LF/HF, b/a, and (b–c–d–e)/a ratio. Furthermore, posture × group interaction effects reached significance for mean PPI, SDPP, LF/HF, and b/a ratio. The study reveals posture-related variations in PPG signal quality and autonomic function, with supine posture yielding the most stable waveforms. These findings may offer preliminary insights into posture-sensitive PPG measures that could support future research and aid in the clinical assessment of diabetic foot complications.

Arterial pulse wave measurement is beneficial in clinical health assessment and is important for effectively diagnosing different types of cardiovascular disease. Computational pulse signal analysis utilizes sensors and signal processing techniques to understand, classify, and predict disease pulse patterns. However, the choice of sensor types impacts the measurement results. This study presents the first comprehensive quantitative comparison of three sensor modalities (acoustic, optical, and pressure) for radial pulse measurement, employing a novel multi-parameter analysis framework that combines time-domain, frequency-domain, and PRV measures. Among various available types, three types of sensors are compared: an acoustic sensor, an optical sensor, and a pressure sensor. Pulse wave signals were recorded from the radial artery of 30 participants using these three sensors, and the performance was evaluated using various feature extraction methods like time domain, frequency domain and pulse rate variability (PRV) measures. Further, statistical analysis (ANOVA) of the PRV measures was carried out to compare the differences in the means of the various PRV measures. Time and frequency domain features varied across sensor types, but no statistical differences were found in PRV measures across sensors. Based on the experimental results, the pressure sensor was found to perform better in capturing comprehensive wrist pulse information. The research provides evidence-based guidelines for sensor selection in pulse wave analysis applications. The findings have direct applications in developing wearable cardiovascular monitoring devices, where sensor choice critically impacts device accuracy and reliability. and clinical settings requiring pulse wave analysis for cardiovascular disease diagnosis.

Design for manufacture usually implies applying various guidelines derived from previous experience to improve part design so it is more compatible with the capabilities of the selected process, resulting in better quality and lower cost. The guidelines can be formulated as dimensionless criteria, enabling quantitative evaluation of a particular aspect of part design. There is, however, no good way to compare two or more designs for all aspects, considering that they may not be equally important. In this work, we employ analytical hierarchy process to determine the relative weights of various criteria for castability evaluation. The criteria are categorised in a three-level hierarchy, with the middle level comprising mould, feeding and gating groups. The prioritisation of criteria along with consistency checking of pair-wise comparisons enables a systematic evaluation of alternative product designs for manufacturability. The methodology is illustrated by modifying the product and tooling design of a grey iron bracket casting and estimating the improvement in manufacturability. The results are supported by experiments.

The current study, compares the mechanical performance of four modular TKA prostheses based on von Mises stress distribution in the tibial insert. Three-dimensional finite element (FE) models of a cruciate retaining type modular prosthesis and three posterior stabilized (PS) type modular prostheses namely: anterior slide, modular post and double cam, were developed. A compressive load of 2600 N was applied to the FE models at flexion angles of 00, 150, 300, 600 and 900. Von Mises stress was evaluated on all the modular parts of the prostheses and compared with the yield strength of the corresponding material. Von Mises stress in all the parts were below the yield strength of their corresponding material except for tibial insert of anterior slide design at high flexion angle. Von Mises stress above the yield strength in the tibial insert of anterior slide design, was due to edge loading in the post and it demonstrates the likelihood of mechanical failure by delamination type of wear.

Purpose Additive manufacturing of metallic scaffolds using laser powder bed fusion is challenging because of the accumulation of extra material below overhanging and horizontal surfaces. It reduces porosity and pore size and increases the effective strut size. These challenges are normally overcome by using volumetric energy density (VED) values lower than the optimum values, which, however, results in poor physio-mechanical properties. The purpose of this study is to assist scaffold manufacturers with a novel approach to fabricate stronger yet accurate scaffolds. Design/methodology/approach This paper presents a strategy for laser exposure that enables fabricating titanium-6–aluminum-4–vanedium (Ti6Al4V) alloy scaffolds with the required properties without compromising the geometric features. The process starts from computer-aided design models sliced into layers; dividing them into core (upper) and downskin (lower) layers; and fabrication using hybrid VED (low values for downskin layers and high values for core layers). Findings While exposing the core layers, laser remelted the downskin layers, resulting in better physio-mechanical properties (surface roughness, microhardness and density) for the whole strut without affecting its dimensional accuracy. A regression equation was developed to select the downskin thickness for a given combination of strut thickness and core VED to achieve the desired range of properties. The proposed approach was validated using microstructure analysis and compression testing. Practical implications This paper is expected to be valuable for the manufacturers of Ti6Al4V scaffolds, in achieving the desired properties. Originality/value This is probably the first time the hybrid VED approach has been applied for obtaining scaffolds with the desirable physio-mechanical and geometrical properties.

Laparoscopic surgery is widely used for treating intra-abdominal conditions involving the gallbladder, pancreas, liver, intestines and reproductive organs. Conventional laparoscopy instruments used in manual surgeries usually have straight shafts and four degrees of freedom (DOF) plus grasping. However, these are insufficient for the complete rotation of the instrument tip. This makes it challenging to access difficult-to-reach organs inside the abdomen during the surgeries. A few robotic instruments available in the market have higher maneuverability but are expensive. Instruments incorporating cable-based mechanisms require replacement after a few sterilization cycles. This paper describes a novel, reusable and affordable multi-DOF laparoscopy instrument that provides two additional DOF: (a) wrist articulation about one axis (wristed yaw) and (b) rotation of the jaw after articulation (jaw roll). The wrist can articulate up to 45° and also roll after articulation. The additional degrees of freedom enable better maneuverability, functionality and reach than conventional laparoscopy instruments. Further, the new instrument employs only rigid links, providing better strength and minimal loss of function after multiple sterilizations. The complete design of the novel instrument, followed by its kinematic analysis and force calculations are explained in this paper, concluding with its manufacture and experimental validation.

Purpose Ti6Al4V alloy patient-customized implants (PCI) are often fabricated using laser powder bed fusion (LPBF) and annealed to enhance the microstructural, physical and mechanical properties. This study aims to demonstrate the effects of annealing on the physio-mechanical properties to select optimal process parameters. Design/methodology/approach Test samples were fabricated using the Taguchi L9 approach by varying parameters such as laser power (LP), laser velocity (LV) and hatch distance (HD) to three levels. Physical and mechanical test results were used to optimize the parameters for fabricating as-built and annealed implants separately using Grey relational analysis. An optimized parameter set was used for fabricating biological test samples, followed by animal testing to validate the qualified parameters. Findings Two optimized sets of process parameters (LP = 100 W, LV = 500 mm/s and HD = 0.08 mm; and LP = 300 W, LV = 1,350 mm/s and HD = 0.08 mm) are suggested suitable for implant fabrication regardless of the inclusion of annealing in the manufacturing process. The absence of any necrosis or reaction on the local tissues after nine weeks validated the suitability of the parameter set for implants. Practical implications To help PCI manufacturers in parameter selection and to exclude annealing from the manufacturing process for faster implant delivery. Originality/value To the best of the authors’ knowledge, this is probably a first attempt that suggests LPBF parameters that are independent of inclusion of annealing in implant fabrication process.

Background In megaprosthetic knee replacement, surgeons use cutting guides that depend on anatomLevel of evidence ical references to determine the ideal cutting plane alignment. In this work, we investigated the accuracy of using femoral cortical surfaces and tibial canal portions as the references. The study aims to improve the design and use of the cutting guides. Materials and methods Sixty-one knee scanograms of 33 patients (mean age around 20 years) diagnosed with osteogenic sarcoma and undergoing distal femur megaprosthetic surgery were acquired. Angles between the selected anatomical references and axis perpendicular to the ideal cutting plane (anatomical axis for femur and mechanical axis for tibia) were measured for both femur and tibia, in coronal view. The smaller the magnitude of the angles, the better the anatomical reference is. Results At the central femoral region, on average, both lateral and medial cortical surfaces give accurate alignment of the ideal cutting plane (0.6° and 0.8°, respectively), with no significant difference ( p  > 0.01). At the distal region, the lateral cortical surface gives significantly better alignment compared to the medial cortical surface ( p  < 0.01), but not as accurate (1.4°) as in the central region. For tibia, the central tibial canal gives significantly accurate alignment of the ideal cutting plane (−0.3°) on average, compared to the proximal tibial canal ( p  < 0.01). Conclusions For a femoral cut, both lateral and medial cortical surfaces are the best anatomical references, but only at the central region. For a tibial cut, the central anatomical axis is the best reference. Level of evidence IV.