News Article | April 18, 2017
A lack of sleep makes everything harder. Focusing, finishing assignments, and coping with everyday stress can become monumental tasks. People with anxiety and depression often have sleep problems. But little has been known about whether or how their poor sleep affects a specific region of the brain known to be involved in regulating negative emotional responses. Researchers at the University of Illinois at Chicago College of Medicine have found that this area of the brain, the dorsal anterior cingulate cortex, may have to work harder to modify negative emotional responses in people with poor sleep who have depression or anxiety. The finding is reported in the journal Depression and Anxiety. The research team, led by Heide Klumpp, assistant professor of psychiatry at UIC, used functional MRI to measure the activity in different regions of the brain as subjects were challenged with an emotion-regulation task. Participants were shown disturbing images of violence -- from war or accidents -- and were asked to simply look at the images and not to try to control their reaction or to "reappraise" what they saw in a more positive light. An example of reappraisal would be to see an image of a woman with a badly bruised face and imagine her as an actress in makeup for a role, rather than as a survivor of violence, Klumpp said. "Reappraisal is something that requires significant mental energy," she said. "In people with depression or anxiety, reappraisal can be even more difficult, because these disorders are characterized by chronic negativity or negative rumination, which makes seeing the good in things difficult." The participants -- 78 patients, 18 to 65 years of age, who had been diagnosed with an anxiety disorder, a major depressive disorder, or both -- also completed a questionnaire to assess their sleep over the previous month. A motion-sensing device called an actigraph measured their awake time in bed, or "sleep efficiency," over a six-day period. The questionnaire results indicated that three out of four participants met criteria for significant sleep disturbance, and the actigraph results suggested the majority had insomnia. Participants who reported poorer sleep on the questionnaire were seen to have less brain activity in the dorsal anterior cingulate cortex during the reappraisal task, while those with lower sleep efficiency based on the actigraph data had higher activity in the DACC. "Because the questionnaire and actigraph measure different aspects of the sleep experience, it is not surprising that brain activity also differed between these measures," said Klumpp. "The questionnaire asks about sleep over the previous month, and answers can be impacted by current mood. Plus, respondents may not be able to accurately remember how they slept a month ago. The actigraph objectively measures current sleep, so the results from both measurements may not match." "Higher DACC activity in participants with lower levels of sleep efficiency could mean the DACC is working harder to carry out the demanding work of reappraisal," Klumpp said. "Our research indicates sleep might play an important role in the ability to regulate negative emotions in people who suffer from anxiety or depression." Co-authors on the study are Julia Roberts, Mary Kapella, Amy Kennedy, Dr. Anand Kumar and Dr. K. Luan Phan, all of UIC. This research was supported by National Institute of Mental Health grants K23MH093679 and R01MH101497, a Brain & Behavior Research Foundation Award, a UIC Campus Research Board award, and UIC Center for Clinical and Translational Research grant UL1RR029879.
Hwang W.-C.,Chosun University |
Lee K.-S.,Dacc LTD. |
Yang Y.-J.,Chosun University |
Yang I.-Y.,Chosun University
International Journal of Precision Engineering and Manufacturing | Year: 2011
The vehicles design should be more concerned on the aspect of securing safety performance, and it also should consider reducing weight of a car body. CFRP (Carbon Fiber Reinforced Plastics) of the advanced composite materials as structure materials for vehicles, has a widely application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness. This study is to investigate the energy absorption characteristics of CFRP hat-shaped section members under the axial impact collapse test. The CFRP and hybrid hat-shaped section members which manufactured from unidirectional prepreg sheets were made of 8ply of these sheets stacked at different angles (±15°, ±45°, ±90°, 0°/90° and 90°/0). According to the interface numbers (2, 3, 4, 6 and 7) CFRP hat-shaped section members were made. The axial impact collapse tests were carried out for each section members. The collapse mode and the energy absorption characteristics of the each member were analyzed. © KSPE and Springer 2011.
Dacc Co. | Date: 2013-03-14
Provided is a method for refurbishing an aircraft brake disk, the method comprising: removing a worn disk from the aircraft brake disk when the disk is worn out up to a set wear amount (Step 1); filling a first mixture in a mold to be a first refurbishment height (Step 2); putting the worn disk on the first mixture (Step 3); filling a second mixture on the worn disk in the mold to be a second refurbishment height (Step 4); pressurizing the first mixture, the worn disk, and the second mixture with a press at once to prepare a molded object (Step 5); removing the molded object from the mold, and then carbonizing the molded object (Step 6); and densifying the carbonized molded object (Step 7), in which the worn disk is subjected to Steps 1 to 7 to prepare a refurbished disk.
DACC Co. | Date: 2013-10-09
A method of manufacturing a carbon-ceramic brake disc of the present invention includes a first step of coating PAN-based carbon fibers with phenolic resins; a second step of carbonizing the PAN-based carbon fibers, which have been coated with the phenolic resins, at a first temperature; a third step of mixing the PAN-based carbon fibers, which have been carbonized at the first temperature, with the phenolic resins to produce a mixture; a fourth step of putting the mixture into a mold to produce a molded body through pressing by means of a press; a fifth step of carbonizing the molded body at a second temperature equal to or less than the first temperature; a sixth step of machining the carbonized molded body; a seventh step of melting silicon to be infiltrated into the machined molded body; and an eighth step of grinding the molded body that has been infiltrated by the silicon. According to the present invention, even after the silicon is melted to be infiltrated into the molded body, the PAN-based carbon fibers are maintained in their original shapes without being changed, so that the PAN-based carbon fibers are not easily broken when a brake is operated. Accordingly, it is possible to consistently maintain strength of the carbon-ceramic brake disc.
Dacc Co. | Date: 2012-07-19
Parts and accessories for aircraft, namely, landing gear, pneumatic deicers; parts and accessories for automobiles, namely, hoods; braking systems for vehicles and parts thereof; braking devices for vehicles, namely, brakes for vehicles, brake discs, brake pads; cycle brakes, brakes for bicycles or cycles, bicycle brakes.
Dacc Co. | Date: 2014-04-22
Parts and accessories for aircraft, namely, braking systems for aircraft and braking devices for aircraft.
DACC Co. | Date: 2013-10-09
The present invention comprises a first disk portion, a second disk portion positioned at a predetermined distance from the first disk portion, a plurality of connection portions connecting the first disk portion and the second disk portion, a plurality of cooling channels formed between the connection portions, wherein each of the first disk portion and the second disk portion includes long fibers, and wherein the connection portion includes short fibers. Also, the present invention comprises forming a first layer in a mold by filling a mixture including long fibers into the mold, inserting a core which has a plurality of through holes into the mold so as to be positioned on the first layer, filling a mixture including short fibers into the through holes of the core, forming a second layer on the core by filling a mixture including long fibers into the mold, and pressure-heating the first layer, the core, and the second layer in the mold. The present invention improves the strength of the connection portions which connect two disk portions and improves efficiency of the heat transfer of the connection portion. Therefore, the frictional heat generated in braking operating is efficiently radiated outside. As a result, it is possible to prevent the thermal distortion of a hot part and a brake disk.
Dacc Co. | Date: 2011-11-28
The present invention relates to a carbon-ceramic brake disc, and the present invention includes a plurality of heat dissipation holes formed in a frictional surface; a curved surface formed between the frictional surface and an inner surface of the hole dissipation hole; and a groove formed at the inner surface of the heat dissipation hole. According to the present invention, in a brake system, when brake pads press the frictional surfaces of the carbon-ceramic brake disc brake to generate braking force, frictional heat in the carbon-ceramic brake disc is effectively dissipated to the outside. That is, the carbon-ceramic brake disc is effectively cooled. Thus, the transferring of the frictional heat generated in the carbon-ceramic brake disc to a hat part is reduced, so that it is possible to minimize deformation of the carbon-ceramic brake disc and the hat part.
Dacc Co. | Date: 2011-11-28
A method of manufacturing a carbon-ceramic brake disc of the present invention includes a first step of mixing carbon fibers with phenolic resins to produce a mixture; a second step of putting the mixture into a mold pressing the mixture by a press to produce a molded body; a third step of carbonizing the molded body; a fourth step of machining the carbonized molded body; a fifth step of coating the machined molded body with liquid-phase phenol to be cured; a sixth step of melting silicon to be infiltrated into the cured molded body that has been coated with the liquid-phase phenol; and a seventh step of grinding the molded body that has been infiltrated by the silicon. According to present invention, the cracks do not occur in the anti-oxidation coating layer.
DACC Co. and Hyundai Motor Company | Date: 2012-10-05
Disclosed is a mounting unit including a bushing having a main part having a penetration hole extending in a lengthwise direction thereof and a flange portion expanding from an upper end of the main part, a stripper bolt having a head portion, a body portion having an insert portion to be inserted into or received in the penetration hole, and a male screw-threaded portion at a leading end of the insert portion. Also disclosed is a brake unit assembled using the mounting unit that has good thermal and mechanical stability at a coupling portion between a disk rotor and a rotor hat.