ASSESSMENT OF TC-99M MDP ABSORBED DOSE AND RESIDENCE TIME AFTER BONE SCAN EXAMINATION: PERSONAL DOSIMETER MEASUREMENTS AND SEMI-EMPIRICAL FORMULA FOR 210 PATIENTS IN TAIWAN

Subject: This study assessed the absorbed dose for patients who underwent Tc-99m Methylene Diphosphonates (MDP) bone scan examination based on a series of personal dosimeter measurements and a derived semi-empirical formula. Material and methods: 210 volunteers among the patients, who were administrated 925 MBq Tc-99m MDP for the bone scan examination in the Department of Nuclear Medicine in the Dalin Tuzchi Hospital, Taiwan, underwent personal dosimeter measurements at 30, 120, and 180[Formula: see text]min after the injection. A personal dosimeter was held at a 30[Formula: see text]cm distance from the patient’s stomach. The acquired data were analyzed to derive the residence time of Tc-99m radionuclide in the patient’s body. Five biological parameters (gender, age, BMI, eGFR, and creatinine) of these 210 patients were collected and processed by the STATISTICA program, yielding a nonlinear 16-term first-order semi-empirical formula for the radionuclide residence time prediction. The respective four- and three-factor calculations, excluding creatinine and eGFR, provided poor correlation. Results and Conclusion: According to the phantom concept, treating a patient’s body as a homogenous spherical ball, a simplified formula was used to assess the absorbed dose rate and magnitude. Therefore, the derived residence time, dose rate, and absorbed dose were [Formula: see text][Formula: see text]min, [Formula: see text]Sv/min, and [Formula: see text]Sv, respectively. These results were lower than those obtained in previous studies, which can be attributed to accelerated radionuclide excretion of patients who drank 2000 cc of water after the procedure, yielding shorter residence times.

Leakage pressures for gasketless superhydrophobic fluid interconnects for modular lab-on-a-chip systems

Chip-to-chip and world-to-chip fluidic interconnections are paramount to enable the passage of liquids between component chips and to/from microfluidic systems. Unfortunately, most interconnect designs add additional physical constraints to chips with each additional interconnect leading to over-constrained microfluidic systems. The competing constraints provided by multiple interconnects induce strain in the chips, creating indeterminate dead volumes and misalignment between chips that comprise the microfluidic system. A novel, gasketless superhydrophobic fluidic interconnect (GSFI) that uses capillary forces to form a liquid bridge suspended between concentric through-holes and acting as a fluid passage was investigated. The GSFI decouples the alignment between component chips from the interconnect function and the attachment of the meniscus of the liquid bridge to the edges of the holes produces negligible dead volume. This passive seal was created by patterning parallel superhydrophobic surfaces (water contact angle ≥ 150°) around concentric microfluidic ports separated by a gap. The relative position of the two polymer chips was determined by passive kinematic constraints, three spherical ball bearings seated in v-grooves. A leakage pressure model derived from the Young–Laplace equation was used to estimate the leakage pressure at failure for the liquid bridge. Injection-molded, Cyclic Olefin Copolymer (COC) chip assemblies with assembly gaps from 3 to 240 µm were used to experimentally validate the model. The maximum leakage pressure measured for the GSFI was 21.4 kPa (3.1 psig), which corresponded to a measured mean assembly gap of 3 µm, and decreased to 0.5 kPa (0.073 psig) at a mean assembly gap of 240 µm. The effect of radial misalignment on the efficacy of the gasketless seals was tested and no significant effect was observed. This may be a function of how the liquid bridges are formed during the priming of the chip, but additional research is required to test that hypothesis.

On Eshelby’s inclusion problem in nonlinear anisotropic elasticity

In this paper, the recent literature of finite eignestrains in nonlinear elastic solids is reviewed, and Eshelby’s inclusion problem at finite strains is revisited. The subtleties of the analysis of combinations of finite eigenstrains for the example of combined finite radial, azimuthal, axial and twist eigenstrains in a finite circular cylindrical bar are discussed. The stress field of a spherical inclusion with uniform pure dilatational eigenstrain in a radially-inhomogeneous spherical ball made of arbitrary incompressible isotropic solids is analyzed. The same problem for a finite circular cylindrical bar is revisited. The stress and deformation fields of an orthotropic incompressible solid circular cylinder with distributed eigentwists are analyzed.

Short term tribological behavior of ceramic and polyethylene biomaterials for hip prosthesis

Reduction in wear of artificial bio-implants results in the release of a lesser amount of wear particles into the blood stream. This paper focuses on analyzing the tribological behavior of ceramic and polyethylene bio-materials experimentally. Four different biomaterials namely Zirconia, Silicon Nitride, UHMWPE (ultra high molecular weight polyethylene) and PEEK (polyether ether ketone) are investigated for friction and wear coefficients using a pin on disc (PoD) tribometer. Alumina (Al2O3) is chosen as the disc material. Polyethylene based UHMWPE and PEEK are used as a pin material with the hemispherical end, while, Zirconia and Silicon Nitride ceramic materials are used in the form of spherical ball. 0.9 % NaCl (saline solution) is used as a lubricant medium. Zirconia showed a better reduction in friction and wear coefficient characteristics under lubrication conditions when compared with polyethylene and other ceramic materials. The estimated friction and wear coefficients would be helpful for surgeons and academicians to choose better wear-resistant bio-compatible materials for effectively design hip prosthesis. The present study compared the tribological behaviors of ceramic materials Si3N4 and ZrO2 and polyethylene materials PEEK and UHMWPE with a ceramic counterpart Al2O3 disc. In the lubrication case, ZrO2 showed a better reduction in friction and wear characteristics while in the dry case UHMWPE showed lesser wear characteristics.

The Behavioral Response to Heat in the Common Bed Bug,Cimex lectularius (Hemiptera: Cimicidae)

The bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.

Sliding of spherical ball on solid lubricating coating combined with wear process

In present paper we show results of ball-on-disk wear experiment of MoS2 film deposited on Ti6Al4V substrate. The ball materials is aluminum oxide. The tests are performed for different surrounding temperature conditions: 20 oC, 200 oC and 350 oC. It is shown that depth of the wear groove increases with increasing surrounding temperature. A finite element modeling approach is next developed to mimic the experimental observations of ball-on-disk wear process. It is based on the assumption of steady state condition developed during short time scale at contact region. The steady state results can next be applied to long time scale in which wear process is numerically simulated. Model results are compared with experimentally obtained wear groove and show satisfactory agreement.

KINEMATICS OF ELEMENTS OF A SPHERICAL BALL BEARING SUSPENSION

Рассмотрены кинематические уравнения связей между элементами сферического шарико-подшипникового подвеса, сепаратором и шариками. На основании уравнения движения сепаратора и шариков определены угловые координаты сепаратора и траектории движения центров масс шариков относительно опорных поверхностей. Аналитические зависимости для определения параметров движения сепаратора и шариков получены для разных соотношений между скоростями вращения ротора, установленного на наружном кольце, и внутреннего кольца подвеса.