Dimensional Accuracy of Dental Casting Patterns Fabricated Using Consumer 3D Printers

Consumer 3D printers have improved considerably due to the evolution of additive manufacturing. This study aimed to examine the accuracy of consumer printers in dental restoration. Cylindrical patterns mimicking a full crown were created and enlarged from 100% to 105% of the original size. Two types of consumer 3D printers, including a fused deposition modeling (FDM) device and a stereolithography (SLA) device, and two types of dental 3D printers, including a multi-jet device and an SLA device, were used to fabricate the patterns. Then, the outer and inner diameters and depths, and surface roughness of the patterns were measured. The changing rates of the outer diameter of models created using dental printers were significantly smaller than those of the models created using consumer printers (p 0.05). However, FDM showed larger surface roughness than dental devices in both axes (p < 0.05). Thus, the SLA consumer printer can be applied to fabricate resin patterns with enlargement editing of 1-3% along the horizontal axis

Effects of Removal Conditions on Mercury Amount Remaining in the Oral Cavity and inside Drainage System after Removing Dental Amalgams

Mercury is produced and drained into the environment by removing dental amalgams, which may cause mercury pollution. This study aimed to clarify the mercury amount remaining in the oral cavity and inside the drain system after removal. The effects of the removal conditions and differences in drainage systems were also investigated. Dental amalgams filled in the tooth and placed in a phantom head were removed using an air turbine under several conditions (two removal methods, absence of cooling water, and intraoral suction). Then, the oral cavity was rinsed with 100 mL of water (oral rinse water), and 500 mL of water was suctioned to wash the inside of the drainage system (system rinse water). Both water samples were collected in two ways (amalgam separator and gas-liquid separator), and their mercury amounts were measured. It was found that the amount of mercury left in the oral cavity and drainage system after dental amalgams removal could be reduced when the amalgams were removed by being cut into fragments as well as using cooling water and intraoral suction. In addition, using amalgam separators can significantly reduce the amount of mercury in the discharge water and prevent the draining of mercury into the environment

CLICK:One-step generation of conditional knockout mice

Abstract Background CRISPR/Cas9 enables the targeting of genes in zygotes; however, efficient approaches to create loxP-flanked (floxed) alleles remain elusive. Results Here, we show that the electroporation of Cas9, two gRNAs, and long single-stranded DNA (lssDNA) into zygotes, termed CLICK (CRISPR with lssDNA inducing conditional knockout alleles), enables the quick generation of floxed alleles in mice and rats. Conclusions The high efficiency of CLICK provides homozygous knock-ins in oocytes carrying tissue-specific Cre, which allows the one-step generation of conditional knockouts in founder (F0) mice

Heat Transfer of a Liquid-Solid Contact in a Subcooled Pool Boiling System : The Second Burnout Regime

The heat flux was measured at the second burnout point of pool boiling over the range of high subcooling of 30 K to 88 K, under atmospheric pressure. The relation between the heat flux and subcooling was obtained by a mathematical model based on the mass-transfer mechanism of evaporation and condensation through a coalescent vapor bubble, and by a kinetic theory of molecules. The relationship equation gave fairly good agreement with the experimental results and showed that the second burnout heat flux did not increase unlimitedly with subcooling, but that it had a maximum value at a certain subcooling

Heat Transfer of a Liquid-Solid Contact in a Subcooled Pool Boiling System : Transition-Type Boiling Regime and Minute Bubble Emission Boiling Regime

This report describes liquid-solid contact behavior in the subcooled pool transition-type boiling regime and the minute bubble emission boiling regime, detected by a void probe that uses a series-resonance circuit. This probe can approach the heated surface within two to three micrometers. The liquid-solid contact state discussed in this report means the nucleate boiling state caused by liquid invasion or Leidenfrost state caused by liquid rush onto the dry part on the heated surface. The dried area on the heated surface was estimated on the basis of the void signal, and the relation between the dried area on the heated surface and the measured heat flux was clarified by introducing a nucleate boiling model

Genetic deletion of the 67‐kDa isoform of glutamate decarboxylase alters conditioned fear behavior in rats

The GABAergic system is thought to play an important role in the control of cognition and emotion, such as fear, and is related to the pathophysiology of psychiatric disorders. For example, the expression of the 67‐kDa isoform of glutamate decarboxylase (GAD67), a GABA‐producing enzyme, is downregulated in the postmortem brains of patients with major depressive disorder and schizophrenia. However, knocking out the Gad1 gene, which encodes GAD67, is lethal in mice, and thus, the association between Gad1 and cognitive/emotional functions is unclear. We recently developed Gad1 knockout rats and found that some of them can grow into adulthood. Here, we performed fear‐conditioning tests in adult Gad1 knockout rats to assess the impact of the loss of Gad1 on fear‐related behaviors and the formation of fear memory. In a protocol assessing both cued and contextual memory, Gad1 knockout rats showed a partial antiphase pattern of freezing during training and significantly excessive freezing during the contextual test compared with wild‐type rats. However, Gad1 knockout rats did not show any synchronous increase in freezing with auditory tones in the cued test. On the other hand, in a contextual memory specialized protocol, Gad1 knockout rats exhibited comparable freezing behavior to wild‐type rats, while their fear extinction was markedly impaired. These results suggest that GABA synthesis by GAD67 has differential roles in cued and contextual fear memory