Giant thermal rectification efficiency by geometrically enhanced asymmetric non-linear radiation.

Thermal rectification is an asymmetric heat transport phenomenon where thermal conductance changes depending on the temperature gradient direction. The experimentally reported efficiency of thermal rectification materials and devices, which are applicable for a wide range of temperatures, is relatively low. Here we report a giant thermal rectification efficiency of 218% by maximizing asymmetry in parameters of the Stefan-Boltzmann law for highly non-linear thermal radiation. The asymmetry in emissivity is realized by sputter-depositing manganese (ε = ∼0.38) on the top right half surface of a polyurethane specimen (ε = ∼0.98). The surface area of the polyurethane side is also dramatically increased (1302%) by 3D printing to realize asymmetry in geometry. There is an excellent agreement between the experimentally measured temperature profiles and finite element simulation results, demonstrating the reliability of the analysis. Machine learning analysis reveals that the surface area is a dominant factor for thermal rectification and suggests novel light-weight designs with high efficiencies. This work may find applications in energy efficient thermal rectification management of electronic devices and housings.

Craniomaxillofacial Changes Using High-Pull J-Hook Headgear and Mini-Implant Anchorage in Adolescents: A Structural Superimposition Method.

OBJECTIVE: The aim of this study was to compare the craniomaxillofacial changes when using high-pull J-hook headgear (HPJH) and mini-implants (MIs) as maxillary anchorage in adolescents. STUDY DESIGN: 40 female adolescents with dentoalvolar protrusion were divided into 2 groups; the HPJH group (n=20) and the MI group (n=20). Lateral cephalograms taken before treatment (T0) and after anterior tooth retraction (T1) were superimposed on the stable structures and then craniomaxillofacial changes were evaluated. RESULTS: The cranial base angle, SNB, and facial angle decreased in the HPJH group but increased in the MI group. ANB decreased more in the MI group than in the HPJH group. Mandibular plane angle increased in the HPJH group but decreased in the MI group. Facial height index increased in the MI group while it showed no change in the HPJH group. Mandibular true rotation occurred clockwise in the HPJH group and counterclockwise in the MI group. Maxillary central incisors were intruded and retracted more in the MI group than in the HPJH group. Maxillary first molars were extruded in the HPJH group and were intruded in the MI group. Maxillary first molars were protracted more in the HPJH group than in the MI group. Mandibular central incisors were retracted more in the HPJH group than the MI group. Mandibular first molars were extruded more in the MI group than in the HPJH group. CONCLUSION: More favorable craniomaxillofacial changes occurred in the MI group than in the HPJH group.

Microimplantes en ortodoncia

La historia del anclaje esqueletal en la ortodoncia. Selección de sitios y tamaños de microimplantes. El desarrollo de nuevos microimplantes ortodóncicos y su aplicación clínica. procedimientos quirúrgicos para la colocación de microimplantes. Consideraciones biomecánicas en el uso de anclaje con microimplantes. Ejemplos clínicos de anclaje con microimplantes. Tasas de éxitos y fracasos de minitornillos y microimplantes

Microimplantes en ortodoncia

La historia del anclaje esqueletal en la ortodoncia. Selección de sitios y tamaños de microimplantes. El desarrollo de nuevos microimplantes ortodóncicos y su aplicación clínica. procedimientos quirúrgicos para la colocación de microimplantes. Consideraciones biomecánicas en el uso de anclaje con microimplantes. Ejemplos clínicos de anclaje con microimplantes. Tasas de éxitos y fracasos de minitornillos y microimplantes

Nonextraction treatment of an open bite with microscrew implant anchorage.

A 16-year-old girl with an anterior open bite was treated with nonextraction therapy that included intrusion of the maxillary and mandibular posterior teeth with microscrew implants. Implants (diameter, 1.2 mm; length, 8 or 6 mm) were placed into alveolar bone near the posterior teeth and used as anchorage for intrusive force. To prevent adverse side effects of buccoversion or linguoversion of the posterior teeth during intrusion, a transpalatal bar and a lingual arch were placed. The 3-mm anterior open bite was corrected in 11 months of treatment, after intrusion of the maxillary and mandibular posterior teeth and autorotation of the mandible. The posterior intrusion relapsed in the early stage of retention, at 8 months; thereafter, no obvious relapse was evident in the vertical position of the molars and the FMA. The treatment mechanics of anterior open bite with posterior intrusion by using microscrew implants were effective but still require a proper retention protocol.

Microscrew implant anchorage sliding mechanics.

AIM: To show the effectiveness of sliding mechanics used with microscrew implants in managing a dentoalveolar protrusion. There are several advantages, including reduced treatment time, simplified treatment mechanics, early profile changes, and elimination of interarch mechanics. MATERIAL AND METHODS: A step-by-step procedure for microscrew implant anchorage sliding mechanics is shown, with records of treated patients, which demonstrate the aforementioned advantages of this technique. The associated biomechanics and theoretical explanation follow. RESULTS: The authors show how the microscrew implant can provide anchorage for en masse retraction of six anterior teeth and the efficiency and ease of the mechanics in managing a dentoalveolar protrusion. CONCLUSION: The microscrew implant offers orthodontic clinicians a minimally intrusive method of intra-arch anchorage that can retract the anterior teeth without the anchorage loss that is expected in conventional techniques. Sliding mechanics used with microscrew implants is shown to be simple and efficient.

Simultaneous incisor retraction and distal molar movement with microimplant anchorage.

AIM: To show how microscrew implants provide orthodontic clinicians with several advantages, eg, the elimination of interarch mechanics for correcting sagittal discrepancies, the reduction of treatment time, the simplification of treatment mechanics, the correction of midline discrepancies without interarch mechanics, and the ability to move entire quadrants rather than individual teeth. MATERIAL AND METHODS: A step-by- step procedure for inserting microscrews is shown, along with several treated patients, which together demonstrate the mentioned advantages of this technique. RESULTS: The authors show how microscrews can rescue treatments that have achieved less than ideal occlusion during the course of therapy and offer readers explicit instructions for placing these microimplants. CONCLUSION: Microscrews offer orthodontic clinicians a minimally intrusive method of intra-arch anchorage that can translate entire quadrants with no untoward reciprocal results that afflict interarch techniques. Clinicians can correct sagittal discrepancies and midline deviations, and gain space for arch-length discrepancies with judicious use of microscrew anchorage.

Nonextraction treatment with microscrew implants.

The maxillary and mandibular posterior teeth were retracted with microscrew implants (1.2 mm in diameter and six to 10 mm long) that were placed into the alveolar bone and used as anchorage. The retraction proceeded without adverse reciprocal effects on the reactive part of the conventional mechanics, such as premolar extrusion and flaring of the incisors. The anterior crowding was resolved without any deleterious effect on the facial profile. En masse movement of the posterior teeth and the whole dentition after anterior tooth alignment can reducethe treatment period and maximize the efficiency of the treatment. The microscrew implants were maintained firmly throughout the treatment and were able to provide an anchorage for retraction of whole dentitions. The efficacy and potency of the microscrew implants aid mechanics in the nonextraction treatment of both labial and lingual treatments.

BMP-2-induced Runx2 expression is mediated by Dlx5, and TGF-beta 1 opposes the BMP-2-induced osteoblast differentiation by suppression of Dlx5 expression.

Intramuscular injection of BMP-2 induces ectopic bone formation in vivo. Similarly, BMP-2 treatment blocks myogenic differentiation and induces osteoblastic transdifferentiation of premyoblastic C2C12 cells. Previous reports suggested that BMP-2-stimulated Runx2 expression could play a pivotal role in transdifferentiation. However, increased Runx2 expression by TGF-beta 1 did not support osteoblast differentiation in vitro. These results indicate that the induction of Runx2 is not sufficient to explain the BMP-induced transdifferentiation. We found that Dlx5 is specifically expressed in osteogenic cells, and is specifically induced by BMP-2 or -4 signaling but not by other osteotrophic signals or other TGF-beta superfamily members. Cycloheximide treatment indicated that Dlx5 was immediately induced by BMP signaling, while Runx2 required de novo protein synthesis. In addition, blocking or overexpressing each transcription factor indicated that Dlx5 is an indispensable mediator of BMP-2-induced Runx2 expression but is not involved in TGF-beta 1-induced Runx2 expression. Moreover, TGF-beta 1 opposed BMP-2-induced osteogenic transdifferentiation through Dlx5 suppression by de novo induction of AP-1. Taken together, these results indicate that Dlx5 is an indispensable regulator of BMP-2-induced osteoblast differentiation as well as the counteraction point of the opposing TGF-beta 1 action.

Ultimate anchorage control.

Titanium microscrews represent an exciting new modality for orthodontic treatment. Retraction, protraction, intrusion and extrusion of anterior and posterior teeth can occur without harmful side effects on adjacent teeth and without reliance on patients' cooperation in wearing elastics, facemasks, or headgears. There are no moving parts in the mechanism, and movements in one jaw occur independently or the other. The results include greater patient acceptance, more comfort, and less breakage of appliances.