Mechanism design of a multi-motion automobile door

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 70).This thesis describes the design and prototype construction of a multi-motion automobile door. This design is intended to provide a unique option for the opening of an automobile by enabling the door to open in two separate directions. A novel design of the door hinge will be presented in this paper which will allow the vehicle door to open in both the standard fashion by being hinged at the front of the vehicle, as well as backwards by being hinged at the rear of the vehicle. The direction in which the door opens can be chosen by the user. A small section of this paper will look at one additional multi-motion door concept. This second design is a split door in which half of the door opens in the standard fashion, while the second half opens up like a gull-wing door.by Sarah T. Edinger.S.M

Skin Impedance Measurements for Acupuncture Research: Development of a Continuous Recording System

Skin impedance at acupuncture points (APs) has been used as a diagnostic/therapeutic aid for more than 50 years. Currently, researchers are evaluating the electrophysiologic properties of APs as a possible means of understanding acupuncture's mechanism. To comprehensively assess the diagnostic, therapeutic and mechanistic implications of acupuncture point skin impedance, a device capable of reliably recording impedances from 100 kΩ to 50 MΩ at multiple APs over extended time periods is needed. This article describes design considerations, development and testing of a single channel skin impedance system (hardware, control software and customized electrodes). The system was tested for accuracy against known resistors and capacitors. Two electrodes (the AMI and the ORI) were compared for reliability of recording over 30 min. Two APs (LU 9 and PC 6) and a nearby non-AP site were measured simultaneously in four individuals for 60 min. Our measurement system performed accurately (within 5%) against known resistors (580 kΩ–10 MΩ) and capacitors (10 nF–150 nF). Both the AMI electrode and the modified ORI electrode recorded skin impedance reliably on the volar surface of the forearm (r = 0.87 and r = 0.79, respectively). In four of four volunteers tested, skin impedance at LU 9 was less than at the nearby non-AP site. In three of four volunteers skin impedance was less at PC 6 than at the nearby non-AP site. We conclude that our system is a suitable device upon which we can develop a fully automated multi-channel device capable of recording skin impedance at multiple APs simultaneously over 24 h

Host natural killer T cells induce an interleukin-4–dependent expansion of donor CD4+CD25+Foxp3+ T regulatory cells that protects against graft-versus-host disease

Although CD4+CD25+ T cells (T regulatory cells [Tregs]) and natural killer T cells (NKT cells) each protect against graft-versus-host disease (GVHD), interactions between these 2 regulatory cell populations after allogeneic bone marrow transplantation (BMT) have not been studied. We show that host NKT cells can induce an in vivo expansion of donor Tregs that prevents lethal GVHD in mice after conditioning with fractionated lymphoid irradiation (TLI) and anti–T-cell antibodies, a regimen that models human GVHD-protective nonmyeloablative protocols using TLI and antithymocyte globulin (ATG), followed by allogeneic hematopoietic cell transplantation (HCT). GVHD protection was lost in NKT-cell–deficient Jα18−/− hosts and interleukin-4 (IL-4)−/− hosts, or when the donor transplant was Treg depleted. Add-back of donor Tregs or wild-type host NKT cells restored GVHD protection. Donor Treg proliferation was lost in IL-4−/− hosts or when IL-4−/− mice were used as the source of NKT cells for adoptive transfer, indicating that host NKT cell augmentation of donor Treg proliferation after TLI/antithymocyte serum is IL-4 dependent. Our results demonstrate that host NKT cells and donor Tregs can act synergistically after BMT, and provide a mechanism by which strategies designed to preserve host regulatory cells can augment in vivo donor Treg expansion to regulate GVHD after allogeneic HCT

Energy functions for protein design I: Efficient and accurate continuum electrostatics and solvation

Electrostatics and solvation energies are important for defining protein stability, structural specificity, and molecular recognition. Because these energies are difficult to compute quickly and accurately, they are often ignored or modeled very crudely in computational protein design. To address this problem, we have developed a simple, fast, and accurate approximation for calculating Born radii in the context of protein design calculations. When these approximate Born radii are used with the generalized Born continuum dielectric model, energies calculated by the 106-fold slower finite difference Poisson-Boltzmann model are faithfully reproduced. A similar approach can be used for estimating solvent-accessible surface areas (SASAs). As an independent test, we show that these approximations can be used to accurately predict the experimentally determined pKas of >200 ionizable groups from 15 proteins