The Posterior Axial Oblique Projection for Radiographic Examination of the Patella.

BACKGROUND: Images of the patella are invaluable for demonstrating fractures, acute injuries, and degenerative pathology of the patellar region. However, quality images of the patella can be difficult to acquire because of the distal femur obscuration. This article presents a method of imaging the patella, using film-screen radiography, computed radiography, or digital radiography that virtually eliminates the problem associated with distal femur obscuration and describes 7 radiography cases that demonstrate the clinical utility of the method. DISCUSSION: The described method of imaging the patella is simple, reproducible, and uses 2 projections-the posterolateral axial oblique and the posteromedial axial oblique-which help eliminate distal femur obscuration. CONCLUSION: The presented method demonstrates the base, body, apical, lateral, and medial borders of the patella without significant distal femur obscuration. In addition, radiologists and orthopedic surgeons express positive impressions of the resulting images' diagnostic usefulness.

Optical characterization of gaps in directly bonded Si compound optics using infrared spectroscopy.

Silicon direct bonding offers flexibility in the design and development of Si optics by allowing manufacturers to combine subcomponents with a potentially lossless and mechanically stable interface. The bonding process presents challenges in meeting the requirements for optical performance because air gaps at the Si interface cause large Fresnel reflections. Even small (35 nm) gaps reduce transmission through a direct bonded Si compound optic by 4% at λ=1.25 µm at normal incidence. We describe a bond inspection method that makes use of precision slit spectroscopy to detect and measure gaps as small as 14 nm. Our method compares low-finesse Fabry-Perot models to high-precision measurements of transmission as a function of wavelength. We demonstrate the validity of the approach by measuring bond gaps of known depths produced by microlithography.

Portable Remote Imaging Spectrometer coastal ocean sensor: design, characteristics, and first flight results.

The design, characteristics, and first test flight results are described of the Portable Remote Imaging Spectrometer, an airborne sensor specifically designed to address the challenges of coastal ocean remote sensing. The sensor incorporates several technologies that are demonstrated for the first time, to the best of our knowledge, in a working system in order to achieve a high performance level in terms of uniformity, signal-to-noise ratio, low polarization sensitivity, low stray light, and high spatial resolution. The instrument covers the 350-1050 nm spectral range with a 2.83 nm sampling per pixel, and a 0.88 mrad instantaneous field of view, with 608 cross-track pixels in a pushbroom configuration. Two additional infrared channels (1240 and 1610 nm) are measured by a spot radiometer housed in the same head. The spectrometer design is based on an optically fast (F/1.8) Dyson design form coupled to a wide angle two-mirror telescope in a configuration that minimizes polarization sensitivity without the use of a depolarizer. A grating with minimum polarization sensitivity and broadband efficiency was fabricated as well as a slit assembly with black (etched) silicon surface to minimize backscatter. First flight results over calibration sites as well as Monterey Bay in California have demonstrated good agreement between in situ and remotely sensed data, confirming the potential value of the sensor to the coastal ocean science community.

Thin films with ultra-low thermal expansion.

Ultra-low coefficient of thermal expansion (CTE) is an elusive property, and narrow temperature ranges of operation and poor mechanical properties limit the use of conventional materials with low CTE. We structured a periodic micro-array of bi-metallic cells to demonstrate ultra-low effective CTE with a wide temperature range. These engineered tunable CTE thin film can be applied to minimize thermal fatigue and failure of optics, semiconductors, biomedical sensors, and solar energy applications.

The 2011 Japanese earthquake: an overview of environmental health impacts.

A magnitude 9.0 earthquake rupturing the Earth's crust nearly 130 km off the east coast of Japan on March 11, 2011, triggered a tsunami that reached the Japanese coast approximately 30 minutes later. The combined effects of the earthquake and tsunami (known as the Tohoku event) devastated the area of northeast Japan, resulting in widespread infrastructure destruction, loss of life, and environmental contamination. Perhaps the longest-lasting impact of the Tohoku event will result from the damage to the nuclear power plants along the coast and the subsequent release of radioactive elements into the environment. This article describes the environmental impacts of the disaster and highlights the interconnectedness among the core areas of environmental health including air quality, water quality, weather/climate change, food safety, healthy housing, waste/sanitation, infectious disease/vector control, radiation, injury prevention, emergency preparedness, and toxicology. The purpose of this article is to provide an overview of the spectrum of the natural disaster and its environmental health impact to the human population. Future scientific analysis may confirm or challenge the information presented here.

Monolithic photolithographically patterned Fluorocur PFPE membrane valves and pumps for in situ planetary exploration.

Photolithographically defined monolithic membrane valves utilizing Fluorocur perfluoropolyether (PFPE) were fabricated and characterized to be essentially unaltered after one million actuations and exposure to the environmental stresses associated with in situ exploration of Mars.

Monolithic Teflon membrane valves and pumps for harsh chemical and low-temperature use.

Microfluidic diaphragm valves and pumps capable of surviving conditions required for unmanned spaceflight applications have been developed. The Pasteur payload of the European ExoMars Rover is expected to experience temperatures ranging between -100 degrees C and +50 degrees C during its transit to Mars and on the Martian surface. As such, the Urey instrument package, which contains at its core a lab-on-a-chip capillary electrophoresis analysis system first demonstrated by Mathies et al., requires valving and pumping systems that are robust under these conditions before and after exposure to liquid samples, which are to be analyzed for chemical signatures of past or present living processes. The microfluidic system developed to meet this requirement uses membranes consisting of Teflon and Teflon AF as a deformable material in the valve seat region between etched Borofloat glass wafers. Pneumatic pressure and vacuum, delivered via off-chip solenoid valves, are used to actuate individual on-chip valves. Valve sealing properties of Teflon diaphragm valves, as well as pumping properties from collections of valves, are characterized. Secondary processing for embossing the membrane against the valve seats after fabrication is performed to optimize single valve sealing characteristics. A variety of different material solutions are found to produce robust devices. The optimal valve system utilizes a membrane of mechanically cut Teflon sandwiched between two thin spun films of Teflon AF-1600 as a composite "laminated" diaphragm. Pump rates up to 1600 nL s(-1) are achieved with pumps of this kind. These high pumping rates are possible because of the very fast response of the membranes to applied pressure, enabling extremely fast pump cycling with relatively small liquid volumes, compared to analogous diaphragm pumps. The developed technologies are robust over extremes of temperature cycling and are applicable in a wide range of chemical environments.

Reconstitution of ion channels in agarose-supported silicon orifices.

A silicon wafer with eight individually addressable microfabricated orifices was used for ion channel reconstitution and single-channel recording. A spin-on fluoropolymer created an insulating, hydrophobic interface that was more stable than silane. Total capacitance of the membranes was <10 pF, making it easy to evaluate bilayer formation by capacitance change. Orifices of 50-250 microm diameter were tested for ease and stability of bilayer formation; only those >100 microm resulted in ion channel function. Bilayers were formed over an agarose supporting layer by application of lipid in decane with a paintbrush; a second layer of agarose could then be added to stabilize the structure and prevent evaporation. Microfluidic wells were constructed on glass plates for ease of assembly and visualization of fluid flow, as well as high-resolution microscopy for studies using fluorescent lipids and channels. The microfluidics consisted of reversibly bonded silicone rubber (PDMS), so that the entire device could be washed and reused. Total electrical noise in the device was low enough to permit single-channel resolution. Successful channel insertions were observed with a self-assembling ionophore (alamethicin) as well as a complex, vesicle-associated mammalian channel (human glycine receptor, GlyR). A "hands-free" approach to bilayer formation was also tested, where lipid in solvent was applied to the wafer by spin-coating, dried, and then "sandwiched" between layers of agarose above and below the nitride. Electrical properties consistent with bilayers were observed and alamethicin recordings were obtained, however this method is not compatible with the fusion of vesicles containing mammalian channels.

Blazed grating fabrication through gray-scale Xray lithography.

Blazed gratings have been fabricated using gray-scale X-ray lithography. The gratings have high efficiency, low parasitic light, and high groove quality. The fabrication technique and resist characterization are described. The gratings can be generated over a considerable range of distances from the X-ray mask, thus demonstrating the ability to write gratings on a substrate of effectively arbitrary shape.