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The aim of this study is to describe an improved experimental substrate for the mechanical testing of patient-specific implants fabricated using direct metal additive manufacturing processes. This method reduces variability and sample size requirements and addresses the importance of geometry at the bone/implant interface.

Short-fiber glass/resin materials for cortical bone and polyurethane foam materials for cancellous bone were evaluated using standard tensile coupons. A method for fabricating bone analogs with patient-specific geometries using rapid tooling is presented. Bone analogs of a canine radius were fabricated and compared to cadaveric specimens in several biomechanical tests as validation.

The analog materials exhibit a tensile modulus that falls within the range of expected values for cortical and cancellous bone. The tensile properties of the cortical bone analog vary with fiber loading. The canine radius models exhibited similar mechanical properties to the cadaveric specimens with a reduced variability.

Additional replications involving different bone geometries, types of bone and/or implants are required for a full validation. Further, the materials used here are only intended to mimic the mechanical properties of bone on a macro scale within a relatively narrow range. These analog models have not been shown to address the complex microscopic or viscoelastic behavior of bone in the present study.

Scientific data on the formulation and fabrication of bone analogs are absent from the literature. The literature also lacks an experimental platform that matches patient-specific implant/bone geometries at the bone implant interface.

From when we, as humans, first lashed a pointed stone to a split straight stick to make a more effective spear for hunting to now when we fasten and bond ablative ceramic tiles to the frail metal skin of the Space Shuttle to allow safe re‐entry from manned excursions into space, joining has been a pragmatic, albeit critically important, fabrication process. As we move beyond the Industrial Age to the ages of Information Technology, Nanotechnology, and Biotechnology, joining must move from a secondary process for manufacturing objects or articles from pre‐synthesized and pre‐shaped materials to a primary process for combining materials into fundamental structures as these structures and even materials are being synthesized; where the boundary between the materials and the structure becomes blurred. This paper attempts to catch a glimpse of the future where joining comes of age to become an enabling technology practiced as much or more by technicians or physicians than as a trade practiced by helmeted welders or hard‐hatted riveters.

The complications caused by metallic orthopaedic bone screws like stress-shielding effect, screw loosening, screw migration, higher density difference, painful reoperation and revision surgery for screw extraction can be overcome with the bioabsorbable bone screws. This study aims to use additive manufacturing (AM) technology to fabricate orthopaedic biodegradable cortical screws to reduce the bone-screw-related-complications.

The fused filament fabrication technology (FFFT)-based AM technique is used to fabricate orthopaedic cortical screws. The influence of various process parameters like infill pattern, infill percentage, layer height, wall thickness and different biological solutions were observed on the compressive strength and degradation behaviour of cortical screws.

The porous lattice structures in cortical screws using the rapid prototyping technique were found to be better as porous screws can enhance bone growth and accelerate the osseointegration process with sufficient mechanical strength. The compressive strength and degradation rate of the screw is highly dependent on process parameters used during the fabrication of the screw. The compressive strength of screw is inversely proportional to the degradation rate of the cortical screw.

The present study is focused on cortical screws. Further different orthopaedic screws can be modified with the use of different rapid prototyping techniques.

The use of rapid prototyping techniques for patient-specific bone screw designs is scantly reported. This study uses FFFT-based AM technique to fabricate various infill patterns and porosity of cortical screws to enhance the design of orthopaedic cortical screws.

Successive Approximation Register-Analog to Digital Converter (SAR-ADC) has been achieved notable technological advancement since the past couple of decades. However, it’s not accurate in terms of size, energy, and time consumption. Many projects proposed to make it energy efficient and time-efficient. Such designs are unable to deliver two parallel outputs.

To this end, this study introduced an ultra-low-power circuitry for the two blocks (bootstrap and comparator) of 11-bit SAR-ADC. The bootstrap has three sub-parts: back-bone, left-wing and right-wing, named as bat-bootstrap. The comparator block has a circuitry of the two comparators and an amplifier, named as comp-lifier. In a bat-bootstrap, the authors plant two capacitors in the back-bone block to avoid the patristic capacitance. The switching system of the proposed design highly synchronized with the short pulses of the clocks for high accuracy. This study simulates the proposed circuits using a built-in Cadence 90 nm Complementary Metal Oxide Semiconductor library.

The results suggested that the response time of two bat-bootstrap wings and comp-lifier are 80 ns, 120 ns, and 90 ns, respectively. The supply voltage is 0.7 V, wherever the power consumption of bat-bootstrap, comp-lifier and SAR-ADC are 0.3561µW, 0.257µW and 35.76µW, respectively. Signal to Noise and Distortion Ratio is 65 dB with 5 MHz frequency and 25 KS/s sampling rate. The input referred noise of the amplifier and two comparators are 98µVrms, 224µVrms and 224µVrms, respectively.

Two basic circuit blocks for SAR-ADC are introduced, which fulfill the duality approach and delivered two outputs with highly synchronized clock pulses. The circuit sharing concept introduced for the high performance SAR-ADCs.

To investigate the effect of operation parameters and printing configuration on the manufacturability of moulds in the manufacture of tissue engineering scaffolds using a 3D printing system.

The scaffold moulds were built using proprietary biocompatible materials using a modified Solidscape T66 ink‐jet printing system. The manufacturability of biological scaffold moulds has been investigated in terms of resolution, accuracy, and minimum and maximum manufacturable features.

The results demonstrated that the 3D system used in this study is able to fabricate structures with high reproducibility and flexibility. It was found that thermal degradation of BioSupport material had an adverse effect on resolution and accuracy of moulds printed for scaffold manufacturing. The maximum features, including maximum length and height, are geometrical dimension and orientation dependent. The system could produce a longer and higher features when the mould was aligned perpendicular to the axis of the mill than that parallel to the axis of the mill. The bigger the cross‐sectional area, the longer/higher the manufacturable feature the machine can produce. The accuracy and resolution are attributed to the size of the molten droplet of BioBuild that caused local melting of the support layer and which partially diffused into the support layer.

The results provide a guide to the design and fabrication of precision scaffold for tissue engineering using biocompatible materials.

This paper describes a method and process to evaluate the manufacturability of a scaffold mould using 3D printing technique. The limits to mould design are established, it could be extended to other solid freeform fabrication systems for effective operation and precision control.

Long-duration spaceflight missions require many hours of pre-mission and inflight training to develop and maintain team skills. Current training flows rely heavily on expert instructors, while current inflight mission operations are supported by a complex series of support teams at Mission Control. However, future exploration space missions will not have real-time communications with ground-based experts at Mission Control. Portable intelligent tutoring systems may help streamline future training, reducing the burden on expert instructors and crew training time, and allowing for inflight support to mitigate negative effects of the loss of real-time communications. In this chapter, we discuss the challenges of long-duration exploration missions, and outline the myriad possibilities in which intelligent tutoring systems will enhance the crew performance and functioning.

This study aims to elucidate the relationship between nutritional status and various biochemical parameters and migraine symptoms.

The disability of individuals aged 19–64 years old with episodic migraine (n = 80, female n = 64, male n = 16) was assessed with the Migraine Disability Assessment Scale, and migraine severity was evaluated with the visual analog scale. The metabolic risks of individuals were determined by analyzing body composition, various biochemical parameters and anthropometric measurements. Nutrients and energy intake levels were measured using the food consumption recording form.

Body muscle mass percentage was correlated directly with migraine severity and inversely with the attack duration (r = 0.26, p = 0.01 and r = −0.29, p = 0.007, respectively). High bone mass was associated with low attack frequency (r = −0.23, p = 0.03), while high body fat percentage was associated with long attack duration (r = 0.28, p = 0.009). A significant direct correlation was found between total cholesterol level and migraine severity and attack duration (r = 0.25, p = 0.02) and between triglyceride level and attack duration (r = 0.26, p = 0.01). There was a direct correlation between serum thyroxine (T4) level and migraine attack severity (r = 0.23, p = 0.03). There was a significant direct correlation between energy and carbohydrate intake and migraine severity (r = 0.26, p = 0.02 and r = 0.30, p = 0.009, respectively), protein and vitamin B2 intake and attack frequency (r = 0.24, p = 0.03 and r = 0.23, p = 0.04, respectively) and an inverse correlation between monounsaturated fatty acid, fiber and vitamin C intake and migraine severity score (r = −0.35, p = 0.002; r = −0.25, p = 0.02; and r = −0.41, p = 0.001, respectively).

The findings confirm that nutritional status, body composition and some biochemical parameters can affect the course of migraine.

Rtsa-byugs, a massage oil from Bhutan, is a traditional herbal formula known for its anti-inflammatory properties and used in osteoarthritis treatment. This study investigates the efficacy of rtsa-byugs vs diclofenacgel in relieving knee pain in osteoarthritis patients.

A single-blind, randomized controlled trial was conducted amongst osteoarthritis knee patients at an orthopedic outpatient department of Thammasat University Hospital. Participants were randomly allocated to the rtsa-byugs (N = 31) or the Diclofenac gel (N = 31) group. Primary outcomes were assessed by the knee injury and osteoarthritis outcome scores (KOOS), visual analog scale (VAS) and goniometer at day 0, 1, 3, 7.

62 participants completed the study. The result of the KOOS scores demonstrated a significant improvement of symptoms at the end of the study in both treatment groups. Improvement of symptoms, pain, daily life living, sport and recreational score and quality of life assessment showed a significant difference from baseline (p < 0.001) within both groups. The quality of life score for the rtsa-byugs group increased significantly on day 3 and 7. The VAS score in both groups decreased with a significant difference from baseline to day 7. The mean value of extension of angle measurement was decreased in day 7, and the mean of flexion score increased in both groups when compared with the baseline.

The duration of the study was very limited and included a small sample consisting of men and women.

Rtsa-byugs is safe and effective in relieving pain from osteoarthritis of the knee and can be used as an alternative treatment for knee osteoarthritis.

Ultrasound is a well-established technology in medical science, though many of the conventional measurement systems (hydrophones and radiation force balances [RFBs]) often lack accuracy and tend to be expensive. This is a significant problem where sensors must be considered to be “disposable” because they inevitably come into contact with biological fluids and expense increases dramatically in cases where a large number of sensors in array form are required. This is inevitably the case where ultrasound is to be used for the in vitro growth stimulation of a large plurality of biological samples in tissue engineering. Traditionally only a single excitation frequency is used (typically 1.5 MHz), but future research demands a larger choice of wavelengths for which a single broadband measurement transducer is desirable. Furthermore, because of implementation conditions there can also be large discrepancies between measurements. The purpose of this paper deals with a very cost-effective alternative to expensive RFBs and hydrophones.

Utilization of cost-effective piezoelectric elements as broadband sensors.

Very effective results with equivalent (if not better) accuracy than expensive alternatives.

This paper concentrates on how very cost-effective piezoelectric ultrasound transducers can be implemented as sensors for ultrasound power measurements with accuracy as good, if not better than those achievable using radiation force balances or hydrophones.