Fred R. Beyette

Zinc Detection in Serum by Anodic Stripping Voltammetry on Microfabricated Bismuth Electrodes.

Zinc (Zn) homeostasis is required for a functional immune system. Critically ill patients often exhibit decreased Zn serum concentrations and could potentially benefit from Zn supplementation as a therapeutic strategy. However, the conventional approaches to monitoring Zn are time consuming and costly. This work reports on detection of Zn by anodic stripping voltammetry (ASV) on bismuth electrodes in a microfabricated electrochemical cell. The working potential window of the electrodeposited bismuth film electrode was investigated by cyclic voltammetry, while square wave ASV was used for measuring Zn in acetate buffer and blood serum. Conditions critical to sensing, such as preconcentration potential, preconcentration time, and buffer pH, were optimized for Zn detection. The sensor was successfully calibrated with pH 6 acetate buffer in the physiologically-relevant range of 5 μM to 50μM Zn and exhibited well-defined and highly repeatable peaks. The sensor was used to demonstrate measurement of Zn in blood serum digested in HCl. The results of this work show that Zn detection in serum is possible with smaller sample volumes (μL vs. μL) and faster turnaround time (hours vs. days) as compared with the conventional spectroscopic methods.

Point-of-Care Technologies for Health Care

The increasingly global focus on health care issues continues to underline the importance of point-of-care technologies and their ability to provide cost-effective solutions that address many unmet health care needs. Further, the current crisis in health care costs has critically underscored the need for research and development into highly effective, but low cost means of delivering health care. With a focus on providing clinically actionable information at or near the patient, point-of-care devices provide clinicians with information that is critical to the management of patient care while they are still with the patient. Rapid information results in various advantages for POC testing in different kinds of health care settings. In primary care settings in developed countries, the shortened timeline between testing and availability of results reduces the need for extra office visits or follow-up phone calls to convey testing results and adjust clinical intervention. This strategy can reduce cost and increase access of otherwise underserved populations to medical care. For diseases that are infectious, such as sexually transmitted infections or respiratory diseases, POC testing can facilitate treatment modalities quickly, thus preventing further spread of the infection for better and timely clinical management. In acute care settings, timely access to diagnostic information is most critical for providing an effective medical response. In disaster settings, POC diagnostics can speed triage and enable rapid establishment and delivery of medical services.The increasingly global focus on health care issues continues to underline the importance of point-of-care technologies and their ability to provide cost-effective solutions that address many unmet health care needs. Further, the current crisis in health care costs has critically underscored the need for research and development into highly effective, but low cost means of delivering health care. With a focus on providing clinically actionable information at or near the patient, point-of-care devices provide clinicians with information that is critical to the management of patient care while they are still with the patient. Rapid information results in various advantages for POC testing in different kinds of health care settings. In primary care settings in developed countries, the shortened timeline between testing and availability of results reduces the need for extra office visits or follow-up phone calls to convey testing results and adjust clinical intervention. This strategy can reduce cost and increase access of otherwise underserved populations to medical care. For diseases that are infectious, such as sexually transmitted infections or respiratory diseases, POC testing can facilitate treatment modalities quickly, thus prevent ing further spread of the infection for better and timely clinical management. In acute care settings, timely access to diagnostic information is most critical for providing an effective medical response. In disaster settings, POC diagnostics can speed triage and enable rapid establishment and delivery of medical services. While in the developed world, POC testing is primarily de signed as an adjunct to central lab testing, not as replacement, POC testing can enable local health care providers to deliver cost-effective care in developing countries or at rural locations with lack of access to central laboratory infrastructure. Further, a growing number of point-of-care technologies enable clinicians to remotely assess/monitor patients who are home bound or unable to meet the clinician in their clinical setting. The underlying theme is to multiply the effectiveness of physicians by providing better/faster information that enables timely delivery and management of health care.

Micromachined arrays of cantilevered glass probes

We describe the fabrication and characterization of cantilevered glass probe arrays. Individual probes have tapered shafts that are 175 microm square at the base and 200 nm square at the pyramidal tip. Each array contains as many as eight probes 10-20 mm long at 450-microm center-to-center spacing, fabricated from a single glass wafer by a combination of dicing and chemical etching. Optical signal losses of individual probes were measured to be of the order of 1 dB/cm. High-density data storage and page-oriented retrieval are the potential applications of the arrays.

Time-critical neurological emergencies: the unfulfilled role for point-of-care testing

BackgroundNeurological emergencies are common and frequently devastating. Every year, millions of Americans suffer an acute stroke, severe traumatic brain injury, subarachnoid hemorrhage, status epilepticus, or spinal cord injury severe enough to require medical intervention.AimsFull evaluation of the diseases in the acute setting often requires advanced diagnostics, and treatment frequently necessitates transfer to specialized centers. Delays in diagnosis and/or treatment may result in worsened outcomes; therefore, optimization of diagnostics is critical.MethodsPoint-of-care (POC) testing brings advanced diagnostics to the patient’s bedside in an effort to assist medical providers with real-time decisions based on real-time information. POC testing is usually associated with blood tests (blood glucose, troponin, etc.), but can involve imaging, medical devices, or adapting existing technologies for use outside of the hospital. Noticeably missing from the list of current point-of-care technologies are real-time bedside capabilities that address neurological emergencies.ResultsUnfortunately, the lack of these technologies may result in delayed identification of patients of these devastating conditions and contribute to less aggressive therapies than is seen with other disease processes. Development of time-dependent technologies appropriate for use with the neurologically ill patient are needed to improve therapies and outcomes.ConclusionPOC-CENT is designed to support the development of novel ideas focused on improving diagnostic or prognostic capabilities for acute neurological emergencies. Eligible examples include biomarkers of traumatic brain injury, non-invasive measurements of intracranial pressure or cerebral vasospasm, and improved detection of pathological bacteria in suspected meningitis.

CMOS-based photoreceiver arrays for page-oriented optical storage access

We report on the design, characterization, and page-oriented read demonstration of a 5/spl times/5 photoreceiver array fabricated within the technology constraints of a standard 1.2-/spl mu/m CMOS fabrication process. These monolithic circuits include a silicon-based photodetector, a multistage current amplifier, and a thresholding circuit that allows the photoreceiver sensitivity to be tuned over a wide range of optical power levels. In addition to characterizing the performance of individual photoreceiver circuits, we demonstrate the ability to interface directly with very large scale integration logic circuits. Finally, a 5/spl times/5 photoreceiver array is used to detect and then display a two-dimensional pattern of bits arranged in a page-oriented data format.

High-density Er-implanted GaN optical memory devices

Upconversion emission has been obtained from Er-focused ion-beam (FIB) implanted GaN. Visible green emission at the 522- and 546-nm range were excited with infrared (IR) laser sources at either 840 or 1000 nm, or with both lasers simultaneously. By implanting closely spaced patterns with the FIB, we demonstrated the concept of storing data in Er-implanted GaN. Information stored as data bits consists of patterns of implanted locations as logic 1 and unimplanted locations as logic 0. The photon upconversion process in Er ions is utilized to read the stored information. This process makes use of the IR lasers to excite visible emission. The integrated upconversion emission power was measured to be ~40 pW when pumped by a 840-nm laser at 265 mW and by a 1000-nm laser at 208 mW. Patterns as small as 0.5 mum were implanted and read. Three-dimensional optical memory based on rare-earth-doped semiconductors could in theory approach a storage capacity of 10(12) bits/cm(3).

The circuit designs of an SRAM based look-up table for high performance FPGA architecture

Look-up table (LUT) circuits are the core component of all Field Programmable Gate Arrays (FPGAs) architectures. Although considerable research has been done regarding the high-level architecture of different LUTs, very little has been done on the circuit-level description of the LUT. Though traditional LUT designs use NMOS transistors to implement pass-gates that save area and increase speed, large LUT designs require several pass gates in series. Unfortunately, multiple pass transistors in series will degrade the logic high level and thus jeopardize signal integrity. This paper explores different circuit-level implementations of the LUT circuitry with consideration towards the relative design trade-offs.

Feasibility of Energy Harvesting Techniques for Wearable Medical Devices

Wearable devices are arguably one of the most rapidly growing technologies in the computing and health care industry. These systems provide improved means of monitoring health status of humans in real-time. In order to cope with continuous sensing and transmission of biological and health status data, it is desirable to move towards energy autonomous systems that can charge batteries using passive, ambient energy. This not only ensures uninterrupted data capturing, but could also eliminate the need to frequently remove, replace, and recharge batteries. To this end, energy harvesting is a promising area that can lead to extremely power-efficient portable medical devices. This paper presents an experimental prototype to study the feasibility of harvesting two energy sources, solar and thermoelectric energy, in the context of wearable devices. Preliminary results show that such devices can be powered by transducing ambient energy that constantly surrounds us.

Point-of-Care Device for Quantification of Bilirubin in Skin Tissue

Steady state diffuse reflectance spectroscopy is a nondestructive method for obtaining biochemical and physiological information from skin tissue. In medical conditions such as neonatal jaundice excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. Diffuse reflectance measurement of the skin tissue can provide real time assessment of the progression of a disease or a medical condition. Here we present a noninvasive point-of-care system that utilizes diffuse reflectance spectroscopy to quantifying bilirubin from skin reflectance spectra. The device consists of an optical system integrated with a signal processing algorithm. The device is then used as a platform to study two different spectral databases. The first spectral database is a jaundice animal model in which the jaundice reflectance spectra are synthesized from normal skin. The second spectral database is the spectral measurements collected on human volunteers to quantify the different chromophores and other physical properties of the tissue such as Hematocrit, Hemoglobin, etc. The initial trials from each of these spectral databases have laid the foundation to verify the performance of this bilirubin quantification device.

Experimental desktop 3D printing using dual extrusion and water-soluble polyvinyl alcohol

Purpose – This paper aims to discuss the use of polyvinyl alcohol (PVA) as a water-soluble support material in desktop three-dimensional (3D) printing. Using a water-soluble material as one of the printing filaments in a dual-extrusion 3D printer provides the flexibility of printing support structures and rafts in complex components and prototypes. This paper focuses on the challenges of acrylonitrile butadiene styrene (ABS)–PVA dual-extrusion printing, and optimal settings and techniques for such hybrid printing. Design/methodology/approach – Several hybrid ABS–PVA parts were printed using a commercial desktop 3D printer. An experimental study was designed to examine the solubility of the PVA support in water by varying four different parameters: length of time in water, water temperature, stirring rate and PVA surface area. The rate of PVA solubility in water was then used to examine its relationship with each parameter. Findings – Numerous problems were encountered while printing ABS–PVA printing parts...