MCNC Research and Development Institute

The immunomodulatory effects of live or non-viable lactic acid bacteria have been extensively investigated. We reported that oral intake of heat-killed Lactobacillus plantarum L-137 (HK L-137) augmented innate and acquired immunity in mice and human subjects. To examine the effects of HK L-137 intake on upper respiratory tract infection (URTI) symptoms and immune functions in human subjects, a randomised, double-blind, placebo-controlled, parallel study was conducted in subjects with high psychological stress levels. A total of seventy-eight healthy subjects (thirty-three men and forty-five women; mean age 50·6 years) with scores of>41 on eighteen-item subscales of psychological distress in the Brief Job Stress Questionnaire were randomly assigned to receive a tablet containing HK L-137 (10mg) or a placebo tablet daily for 12 weeks. The URTI symptoms were rated once daily on the validated twenty-one-item Wisconsin Upper Respiratory Symptom Survey-21. Immune functions, such as concanavalin A-induced proliferation and percentages of interferon (IFN)-γ- and IL-4-producing CD4 T cells of peripheral blood mononuclear cells (PBMC), and serum IFN-β concentrations were measured every 4 weeks. URTI incidence was significantly lower in the HK L-137 group than in the control group. URTI incidence, duration and severity, and duration of medication showed significant negative correlations with duration of HK L-137 intake. The percentage change from baseline of concanavalin A-induced proliferation of PBMC was significantly greater in the HK L-137 group than in the control group. These findings suggest that daily HK L-137 intake can decrease URTI incidence in healthy subjects, possibly through augmentation of immune functions.

Small distributed data centers and laboratories are becoming increasingly expensive to provision, support, and maintain on their own. In this paper, we discuss how North Carolina State University Virtual Computing Laboratory (VCL) technology can be used to implement distributed reconfigurable data centers and IT (information technology) services in educational institutions. VCL is an open-source implementation of a secure production-level technology for wide-area access to solutions based on real and virtualized computational, storage, network, and software resources. We discuss how this technology scales, what its return on investment is, and how it can deliver computing clouds that offer a mix of resource architectures and ensembles, including those that may integrate traditional mainframe servers.

Organic light emitting diode (OLED) based displays are well suited for fabrication on flexible polymer substrates. In order to achieve the vision of a highly flexible, rollable display, significant progress must be made in understanding and overcoming the mechanical limitations of the component materials. Methodologies and metrics for evaluating thin film components as well as full devices on flexible substrates need to be developed and standardized. A new technique for bend testing is described here and compared to a more traditional technique. One thin film component of flexible OLEDs that must be very mechanically robust is the permeation barrier. It is desirable to have a rapid method to characterize the onset of cracking upon bending of a barrier-coated substrate. We have developed a convenient method that allows characterization of mechanical cracking of flexible permeation barriers. In addition, transparent conductors with mechanical properties superior to those of ITO are desired for improved flexibility of displays. We report dramatically improved mechanical properties of multilayer ITO-Ag-ITO films that also exhibit excellent electrical and optical properties. Finally, we show preliminary results from bend tests of complete OLED devices on polymer substrates. The results demonstrate that in addition to evaluating component materials, other factors must be considered for integrated devices, and further investigation on this subject is needed.

An electrostatic MEMS actuator is described for use as an analog micromirror device (AMD) for high performance, broadband, hardware-in-the-loop (HWIL) scene generation. Current state-of-the-art technology is based on resistively heated pixel arrays. As these arrays drive to the higher scene temperatures required by missile defense scenarios, the power required to drive the large format resistive arrays will ultimately become prohibitive. Existing digital micromirrors (DMD) are, in principle, capable of generating the required scene irradiances, but suffer from limited dynamic range, resolution and flicker effects. An AMD would be free of these limitations, and so represents a viable alternative for high performance UV/VIS/IR scene generation. An electrostatic flexible film actuator technology, developed for use as "artificial eyelid" shutters for focal plane sensors to protect against damaging radiation, is suitable as an AMD for analog control of projection irradiance. In shutter applications, the artificial eyelid actuator contained radius of curvature as low as 25um and operated at high voltage (>200V). Recent testing suggests that these devices are capable of analog operation as reflective microcantilever mirrors appropriate for scene projector systems. In this case, the device would possess larger radius and operate at lower voltages (20-50V). Additionally, frame rates have been measured at greater than 5kHz for continuous operation. The paper will describe the artificial eyelid technology, preliminary measurements of analog test pixels, and design aspects related to application for scene projection systems. We believe this technology will enable AMD projectors with at least 512² spatial resolution, non-temporally-modulated output, and pixel response times of <1.25ms.

This paper studies the important fault management issue with focus on the fast restoration mechanisms for optical burst switched (OBS) networks. In order to reduce the burst losses during the restoration process, effective fast restoration schemes are necessary. This is illustrated via two basic fast restoration schemes, the distributed deflection scheme and the local deflection scheme, compared with the slow global routing update mechanism. A novel priority-based QoS restoration scheme is also proposed to provide differentiated restoration services. Through detailed descriptive analysis and a comprehensive simulation study, these fast restoration schemes demonstrate fast restoration process, low fault management overheads, and excellent burst loss performance. As far as we know, this is the first comprehensive study on the restoration mechanisms for OBS networks.

An electrostatic MEMS actuator known as the “Artificial Eyelid” can be used as a micromechanical chopper for IR detectors. The actuator structure consists of a curled polymer/metal film stack which is microfabricated and released from an IR transparent substrate. The film stack is uncurled by applying an electric field between the curled film and the transparent fixed electrode on the substrate. These flexible film actuators can act as IR choppers, providing transmission of radiation to the sensor elements when open (curled) and reflection when closed (uncurled). Arrays of actuators were fabricated on ITO-coated glass substrates and ranged in size from 4 x 4 mm to 7.5 x 15 mm with individual elements ranging from 250 to 500 μm on a side. Actuation for devices with average radius of curvature of 120 μ was consistently achieved at 150-170 V operation with 98-100% of the elements functioning and long lifetimes. IR chopper characteristics were measured using a blackbody source and pyroelectric detector by applying sine and square wave voltage to the actuators at a frequency of 30 Hz. The capability of the artificial eyelid for chopping near- and mid-IR radiation, including future fabrication of devices using NiCo2O4 or NiRh2O4 films for IR transparent electrodes, will be discussed.

Processing techniques that address the interconnect issues required for fabrication of deep sub-micron electronic devices and for three-dimensional (3D) integration of these components will be described. As the interconnect density increases, alternate methods of providing input/output (I/O) leads on a chip are required. One attractive approach to providing increased connectivity is to use through-wafer interconnects. This reduces the interconnect density on the front surface while providing additional I/Os on the back surface. It also provides a convenient mechanism for integrating two or more die to form a 3D integrated structure. Processing techniques under development include: high aspect ratio silicon etching, insulator lining, adhesion/barrier layer deposition, seed layer deposition, electroplating, and chemical mechanical planarization (CMP).

Abstract Microscopy is the art and science of visually observing small objects. Electrons are electrically charged subatomic particles typically responsible for the flow of electrical current. Scanning is a method of observation where the focus of attention is moved in a chosen pattern and desired information is gained by assembling observations in sequence. In a scanning electron microscope (SEM), a beam of electrons is scanned in a regular pattern over a small object, and the image of the object appears on a screen by displaying the image points in synchrony with the movements of the electron beam on the object.A familiar example of image scanning is a television receiver, where a picture is created on a screen by rapidly scanning an electron beam across the phosphor face of the television tube. The beam striking the phosphor produces light, which is seen as a picture. The signal that modulates the electron beam in a television set is created in a television camera, which is scanned in the same way that the television screen is scanned. In a SEM, the signals come from special detectors in the microscope, not from an optical camera. Otherwise, the image display in a SEM is very similar to television. Although it is typical for SEM images to be scanned at a slower rate than are television signals, some SEMs display images at the same speed as television.The most common signal for detection in a SEM is the secondary electron signal. Secondary electrons are low‐speed electrons (having energies less than about 50 eV) that result from the interaction of the primary (i.e. beam) electrons with the sample. The secondary electrons are detected, usually by a scintillator/photomultiplier detector, and the resulting signal modulates the display screen.Secondary electrons are popular because they provide a kind of shading that gives a three‐dimensional appearance to an image, making it easy to visualize the structural relationships of parts of the sample (Figure 1).Other signals provide information of a more analytical nature. The signal produced by backscattered electrons is directly (although not exactly proportionally) related to the atomic number of the material being struck by the primary beam. Diffracted electrons provide information about crystal spacings and orientations in the sample. Induced‐current signals are particularly interesting for studying the response of active electronic components.The resolution of a SEM image depends on the quality of the optical system that forms the electron beam, including the nature of the electron source. Most SEMs can typically resolve objects as small as 10 nm. The resolution of specialized SEMs is better than 1 nm. In contrast, the resolution of light microscopes is limited by the wavelength of light to about 500 nm.The magnification of a SEM is not directly related to the optical system, very unlike a light microscope. The magnifying power of a SEM is related to the ratio between the size of the scan on the object compared to the size of the scan on the image display. In this way a SEM functions like a mechanical pantograph that was used, typically in older days, for copying drawings. If the arms of the pantograph were of equal length, the drawing would be copied the same size. If the arms were adjusted to different lengths, the drawing could be magnified or reduced.The primary advantage of a SEM is that it provides familiar‐looking images of surfaces with higher resolution and greater depth‐of‐field than an optical microscope. Although the images are typically familiar looking, the contrast mechanism in a SEM is not the same as the contrast provided by light, and an observer expecting always to interpret a SEM image the same way as a light image could easily be fooled.As the electron beam consists of electrically charged particles, the sample for SEM observation must either be inherently electrically conducting or must be made electrically conducting to yield good images. Otherwise, electrical charge builds up on the sample, the yield of secondary electrons is changed, and the scanning beam can become erratic. Low‐voltage or low‐vacuum SEMs can be used to reduce the charging problem.

In the SCALPEL system developed by Lucent Technologies, a mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated by high energy electrons. Commercialization of the SCALPEL technology requires a manufacturing infrastructure for mask fabrication. This infrastructure is composed of a mask blank supplier who fabricates the membrane mask structure, and a mask patterning facility that writes and etches the patterns into the high atomic number layer. In collaboration with Lucent Technologies, MCNC has developed and implemented a fabrication process and measurement methodology in an effort to establish a commercially viable manufacturing line for SCALPEL mask blanks. This paper presents the process and measurement methodology, measurement result, the key issues associated with this effort.