48 research outputs found
Patient-specific 3D-printed splint for mallet finger injury
Despite the frequency of mallet finger injuries, treatment options can often be costly, time-consuming, and ill-fitted. Three-dimensional (3D) printing allows for the production of highly customized and inexpensive splints, which suggests potential efficacy in the prescription of casts for musculoskeletal injuries. This study explores how the use of engineering concepts such as 3D printing and topology optimization (TO) can improve outcomes for patients. 3D printing enables the direct fabrication of the patient-specific complex shapes while utilizing finite element analysis and TO in the design of the splint allowed for the most efficient distribution of material to achieve mechanical requirements while reducing the amount of material used. The reduction in used material leads to significant improvements in weight reduction and heat dissipation, which would improve breathability and less sweating for the patient, greatly increasing comfort for the duration of their recovery
Sequence stratigraphy of the petroliferous Dariyan Formation (Aptian) in Qeshm Island and offshore (southern Iran)
Control-based 4D printing: adaptive 4D-printed systems
Building on the recent progress of four-dimensional (4D) printing to produce dynamic structures, this study aimed to bring this technology to the next level by introducing control-based 4D printing to develop adaptive 4D-printed systems with highly versatile multi-disciplinary applications, including medicine, in the form of assisted soft robots, smart textiles as wearable electronics and other industries such as agriculture and microfluidics. This study introduced and analysed adaptive 4D-printed systems with an advanced manufacturing approach for developing stimuli-responsive constructs that organically adapted to environmental dynamic situations and uncertainties as nature does. The adaptive 4D-printed systems incorporated synergic integration of three-dimensional (3D)-printed sensors into 4D-printing and control units, which could be assembled and programmed to transform their shapes based on the assigned tasks and environmental stimuli. This paper demonstrates the adaptivity of these systems via a combination of proprioceptive sensory feedback, modeling and controllers, as well as the challenges and future opportunities they present
First report of Quaternary mammals from the Qalehjough area, Lut Desert, Eastern Iran
Taxonomic study of Quaternary mammal remains from the Qalehjough fossil site, eastern Iran, has resulted in the identification of two mammal orders, Artiodactyla and Perissodactyla, with four families and six taxa. Of particular note was the recovery of Stephanorhinus and a caballoid horse. These remains have provided the first opportunity to examine Late Quaternary faunal assemblages in the northern parts of the Lut Desert, eastern Iran. The Qalehjough faunal assemblage documents some zoogeographic characteristics of the eastern Iranian Plateau, and suggests that palaeoenvironments in this part of Iran during the Pleistocene were more humid and wooded than today. The disappearance of rhinoceroses and caballoid horses from this region is most likely a result of climate change and concomitant habitat loss
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Direct 3D printing of a two-part silicone resin to fabricate highly stretchable structures
The direct ink writing (DIW) method of 3D-printing liquid resins has shown promising results in various applications such as flexible electronics, medical devices, and soft robots. A cost-effective extrusion system for a two-part high-viscous resin is developed in this article to fabricate soft and immensely stretchable structures. A static mixer capable of evenly mixing two viscous resins in an extremely low flow regime is designed based on the required mixing performance through a series of biphasic computational fluid dynamics analyses. The printing parameters of the extrusion system are determined empirically, and the mechanical properties of the printed samples are compared to their molded counterparts. Furthermore, some potential applications of the system in soft robotics and medical training are demonstrated. This research provides a clear guide for utilizing DIW to 3D print highly stretchable structures
Manufacture Techniques of Chitosan-Based Microcapsules to Enhance Functional Properties of Textiles
In recent years, the textile industry has been moving to novel concepts of products, which could deliver to the user, improved performances. Such smart textiles have been proven to have the potential to integrate within a commodity garment advanced feature and functional properties of different kinds. Among those functionalities, considerable interest has been played in functionalizing commodity garments in order to make them positively interact with the human body and therefore being beneficial to the user health. This kind of functionalization generally exploits biopolymers, a class of materials that possess peculiar properties such as biocompatibility and biodegradability that make them suitable for bio-functional textile production. In the context of biopolymer chitosan has been proved to be an excellent potential candidate for this kind of application given its abundant availability and its chemical properties that it positively interacts with biological tissue. Notwithstanding the high potential of chitosan-based technologies in the textile sectors, several issues limit the large-scale production of such innovative garments. In facts the morphologies of chitosan structures should be optimized in order to make them better exploit the biological activity; moreover a suitable process for the application of chitosan structures to the textile must be designed. The application process should indeed not only allow an effective and durable fixation of chitosan to textile but also comply with environmental rules concerning pollution emission and utilization of harmful substances. This chapter reviews the use of microencapsulation technique as an approach to effectively apply chitosan to the textile material while overcoming the significant limitations of finishing processes. The assembly of chitosan macromolecules into microcapsules was proved to boost the biological properties of the polymer thanks to a considerable increase in the surface area available for interactions with the living tissues. Moreover, the incorporation of different active substances into chitosan shells allows the design of multifunctional materials that effectively combine core and shell properties. Based on the kind of substances to be incorporated, several encapsulation processes have been developed. The literature evidences how the proper choices concerning encapsulation technology, chemical formulations, and process parameter allow tuning the properties and the performances of the obtained microcapsules. Furthermore, the microcapsules based finishing process have been reviewed evidencing how the microcapsules morphology can positively interact with textile substrate allowing an improvement in the durability of the treatment. The application of the chitosan shelled microcapsules was proved to be capable of imparting different functionalities to textile substrates opening possibilities for a new generation of garments with improved performances and with the potential of protecting the user from multiple harms. Lastly, a continuous interest was observed in improving the process and formulation design in order to avoid the usage of toxic substances, therefore, complying with an environmentally friendly approach
New Method for Designing an Optimum Distributed Cooling System for Effluent Thermal Treatment
Temperature restrictions on aqueous effluents dictate that streams with
a temperature higher than the permitted level needed to pass through
cooling systems to reduce the effluent temperature before discharge. In
this study, by considering the grouping design rules based on pinch
technology, an optimum design for a distributed effluent cooling
system, has been developed. A counter-flow wet cooling tower, with a
mechanical air draft, is also assumed as an effluent thermal treatment
facility in predicting the exit water and air conditions of the tower
in the system. In this new design method, an optimum inlet flow rate to
cooling tower has been achieved by exploring the feasible region. Also,
the evaporation loss effect, flexible design variables, and physical
properties have been incorporated in targeting the optimal conditions
for the cooling tower. A case study is presented to illustrate the
design methodology and the optimization model of cooling systems
A COMPARISON OF CLOMIPHENE CITRATE AND SEQUENTIAL CLOMIPHENE CITRATE PLUS HUMAN MENOPAUSAL GONADOTROPIN FOR USE IN CONJUNCTION WITH INTRAUTERINE INSEMINATION
There are currently ‎many different protocols in use for controlled ovarian hyperstimulation (COH), but the optimal method has ‎not yet been determined. To compare the outcome of COH using ‎clomiphene citrate (CC) versus CC plus human menopausal gonadotropin (hMG) in conjunction with intrauterine insemination (IUI), we studied 117 infertile couples‎. IUI with CC was used in 92 cycles ‎(group A) and IUI with CC plus hMG was used in 66 cycles (group B). ‎Data analysis demonstrated no significant difference between the two ‎groups with respect to patients’ age, duration and type of infertility, prior COH and endometrial thickness and pattern. Group A had a little ‎longer follicular phase length than group B. ‎Pregnancy rate for group A and B were 6.52% and 12.12%, respectively (P= 0.22). ‎Endometrial pattern and thickness had no impact on pregnancy rate. ‎There were no multiple gestation and obvious hyperstimulation syndrome. ‎For patients undergoing controlled ovarian hyperstimulation with IUI, ‎CC plus hMG protocol yields higher pregnancy rate than one using CC, although this ‎difference was not statistically significant because of limitation of number of ‎cycles