Use of fiberglass CAD-CAM post-and-core for rapid orthodontic extrusion of anterior tooth – Case Report

This report describes the restoration of an anterior fractured tooth with a fiberglass CAD-CAM post-and-core followed by rapid orthodontic extrusion. The post space was prepared, the post-and-core was luted and a interim crown was luted to allow the tooth extrusion through the use of orthodontic buttons and elastic rubber bands. A lithium disilicate glass-ceramic crown was luted and the case was followed up after 6 and 12 months.

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Soft actuators (SAs) have been used in many compliant robotic structure and wearable devices, due to their safe interaction with the wearers. Despite advances, the capability of current SAs is limited by scalability, high hysteresis, and slow responses. In this paper, a new class of soft, scalable, and high-aspect ratio fiber-reinforced hydraulic SAs is introduced. The new SA uses a simple fabrication process of insertion where a hollow elastic rubber tube is directly inserted into a constrained hollow coil, eliminating the need for the manual wrapping of an inextensible fiber around a long elastic structure. To provide high adaptation to the user skin for wearable applications, the new SAs are integrated into flexible fabrics to form a wearable fabric sleeve. To monitor the SA elongation, a soft liquid metal-based fabric piezoresistive sensor is also developed. To capture the nonlinear hysteresis of the SA, a novel asymmetric hysteresis model which only requires five model parameters in its structure is developed and experimentally validated. The new SAs-driven wearable robotic sleeve is scalable, highly flexible, and lightweight. It can also produce a large amount of force of around 23 N per muscle at around 30% elongation, to provide useful assistance to the human upper limbs. Experimental results show that the soft fabric sleeve can augment a user’s performance when working against a load, evidenced by a significant reduction on the muscular effort, as monitored by electromyogram (EMG) signals. The performance of the developed SAs, soft fabric sleeve, soft liquid metal fabric sensor, and nonlinear hysteresis model reveal that they can effectively modulate the level of assistance for the wearer. The new technologies obtained from this work can be potentially implemented in emerging assistive applications, such as rehabilitation, defense, and industry.

Ultrasound Assisted Extraction Approach to Test the Effect of Elastic Rubber Nettings on the N-Nitrosamines Content of Ham Meat Samples

Nitrosamines (NAs), which are catalogued as carcinogenic compounds, may be present in meat products due to the conversion of nitrites and as result of migration from elastic rubber nettings used. A method based on ultrasonic assisted extraction coupled with dispersive liquid–liquid microextraction as sample treatment and gas chromatography-mass spectrometry as separation and detection technique was proposed for the determination of twelve NAs in cooked ham samples. The method was validated by evaluating linearity (0.5–1000 ng g−1), matrix effect, sensitivity (detection limits were between 0.15 and 1.4 ng g−1) and precision, which was below 12%. Five NAs were found in the samples with levels ranging from not quantifiable to 40 ng g−1. The effect of the elastic rubber nettings on the nitrosamine content of meat was evaluated by comparing the levels found in products made with several plastics or thread in the presence of additives.

Optimization Design and Experiment of Ear-Picking and Threshing Devices of Corn Plot Kernel Harvester

In order to solve the problems of easy-to-break kernels and substantial harvest losses during kernel harvesting in breeding trials plot of corn, an ear-picking device and a threshing device of corn plot kernel harvester has been optimized. To automatically change the gap of the ear-picking plate, a self-elastic structure with compression spring and connecting rod is used. The ear-picking plate is glued, and an elastic rubber gasket is placed underneath it, which effectively improves the adaptability of the ear-picking device and reduces corn kernel collision damage during ear-picking. To ensure the self-purification of the ear-picking device, a combination of auger sieve hole cleaning device and lateral pneumatic auxiliary cleaning system is used. A dual-axial flow threshing device is designed, which uses a “U”-shaped conveying system to transport maize ears in the threshing chamber. The spacing of the concave sieve may be adjusted, and the residual kernels in the threshing chamber can be cleaned up after harvesting one plot by combining three cleanings, which meets the requirements of no mixing between plots. The force analysis of corn ears in the threshing chamber determines the best design plan for the forward speed, the speed of the second threshing drum, and the threshing gap. The breakage rate and non-threshing rate regression models were created using the quadratic regression orthogonal combination test, and the parameters were optimized using MATLAB. The verification test results showed that when the forward speed was 0.61 m/s, the second threshing drum speed was 500 r/min, and the threshing gap was 40 mm, the breakage rate was 1.47%, and the non-threshing rate was 0.89%, which met the kernel harvesting requirements in corn plots.

Comparative Analysis for the Anti-Vibration Isolation of a Foundation in the Case of an Elevating Mechanism

To study the vibrations of a Multiparker lift lift model, use various models for the lifting mechanism. In order to increase the number of parking spaces in the center of the Romanian capital, it is intended to design a parking lot on several levels above the Dâmbovița river, which would include two elevators for lifting and lowering cars. One of the elevators works as a system of translating cam and roller translating follower and thus, due to transmitting the torque from the electric drive motor to the cam, respectively changing the travel direction at the end of the route, upon starting and stopping, vibrations may occur within the elevator. This system must be supported on a foundation in order to achieve anti-vibration isolation. There are several possibilities to achieve this anti-vibration isolation, among which one can mention the elastic suspensions mounted on springs, rubber mats or standardized elastic rubber elements

A Case Report of Osteomyelitis of Lower End of Tibia and Fibula as a Complication of Elastic Rubber Band Syndrome (Dhaga Syndrome)

Introduction: Rubber band syndrome is a rare acquired condition poorly discussed in literature, when neglected can lead to devastating complications of compartment syndrome and infection of soft tissue and bone as seen in the present case. Rubber band or Dhaga (sacred thread) when worn for prolonged duration can bury into the skin and soft tissue. Case Report: A 12-month-old girl developed osteomyelitis of tibia and fibula as sequelae of misdiagnosis and treatment for this syndrome. Assuming it to be a simple constriction band, incisions were given on medial and lateral aspect of the ankle, later she developed osteomyelitis of the tibia and fibula with in buried rubber band, which was removed and thorough curettage done and achieved good healing of the bones. Conclusion: Rubber band syndrome in not an uncommon condition, but when neglected or misdiagnosed can lead to complications such as compartment syndrome and osteomyelitis of the bones in involved limb as seen in this case. In suspected cases, imaging with sonography and X-ray of involved helps in diagnosis. Keywords: Osteomyelitis, rubber band syndrome, Dhaga syndrome, compartment syndrome.