784 research outputs found
Qualitative website analysis of information on birth after caesarean section
Date of Acceptance: 10/08/2015 © 2015 Peddie et al.Peer reviewedPublisher PD
Terahertz Imagers Based on Metamaterial Structures Monolithically Integrated in Standard CMOS Technologies
Silicon complementary metal oxide semiconductor (CMOS) technologies are arguably the most important asset in the world of electronics. Focal plane arrays (FPAs) are one of the driving forces in the revolution of low-cost, mass produced, compact, and high-resolution imaging devices. The importance of these imaging systems in the visible spectrum has highlighted the need of their implementation into other significant electromagnetic regions such as infrared (IR) and Terahertz (THz). The unique characteristics of THz waves make them ideal for a variety of important applications ranging from security and medical imaging, explosive and drug detection, and non-destructive quality control testing. These applications are possible due to the non-ionizing nature of THz radiation, its transparency to many non-conductive materials, and distinctive spectroscopic fingerprints of a vast number of substances.
Current THz imaging systems are usually restricted to laboratory use due the lack of compact, portable and roomtemperature operated sources and detectors. Therefore, the implementation of CMOS based THz detectors is key to promote the exploitation of low-cost, room-temperature, high-resolution, highly sensitive, and portable THz imaging systems. Here we present the monolithic integration of two types of THz FPAs fabricated in a standard 180 nm CMOS process. The imagers are composed of THz metamaterials (MM) absorbers coupled to a microbolometer, either vanadium oxide (VOx) or silicon pn diode, integrated with readout electronics to form 64 x 64 CMOS FPAs. The suitability of THz imagers for stand-off imaging of concealed objects was demonstrated in transmission mode by capturing images of metallic objects hidden in a manila envelope
A 16 x 16 CMOS amperometric microelectrode array for simultaneous electrochemical measurements
There is a requirement for an electrochemical sensor technology capable of making multivariate measurements in environmental, healthcare, and manufacturing applications. Here, we present a new device that is highly parallelized with an excellent bandwidth. For the first time, electrochemical cross-talk for a chip-based sensor is defined and characterized. The new CMOS electrochemical sensor chip is capable of simultaneously taking multiple, independent electroanalytical measurements. The chip is structured as an electrochemical cell microarray, comprised of a microelectrode array connected to embedded self-contained potentiostats. Speed and sensitivity are essential in dynamic variable electrochemical systems. Owing to the parallel function of the system, rapid data collection is possible while maintaining an appropriately low-scan rate. By performing multiple, simultaneous cyclic voltammetry scans in each of the electrochemical cells on the chip surface, we are able to show (with a cell-to-cell pitch of 456 μm) that the signal cross-talk is only 12% between nearest neighbors in a ferrocene rich solution. The system opens up the possibility to use multiple independently controlled electrochemical sensors on a single chip for applications in DNA sensing, medical diagnostics, environmental sensing, the food industry, neuronal sensing, and drug discovery
An integrated circuit for chip-based analysis of enzyme kinetics and metabolite quantification
We have created a novel chip-based diagnostic tools based upon quantification of metabolites using enzymes specific for their chemical conversion. Using this device we show for the first time that a solid-state circuit can be used to measure enzyme kinetics and calculate the Michaelis-Menten constant. Substrate concentration dependency of enzyme reaction rates is central to this aim. Ion-sensitive field effect transistors (ISFET) are excellent transducers for biosensing applications that are reliant upon enzyme assays, especially since they can be fabricated using mainstream microelectronics technology to ensure low unit cost, mass-manufacture, scaling to make many sensors and straightforward miniaturisation for use in point-of-care devices. Here, we describe an integrated ISFET array comprising 216 sensors. The device was fabricated with a complementary metal oxide semiconductor (CMOS) process. Unlike traditional CMOS ISFET sensors that use the Si3N4 passivation of the foundry for ion detection, the device reported here was processed with a layer of Ta2O5 that increased the detection sensitivity to 45 mV/pH unit at the sensor readout. The drift was reduced to 0.8 mV/hour with a linear pH response between pH 2 – 12. A high-speed instrumentation system capable of acquiring nearly 500 fps was developed to stream out the data. The device was then used to measure glucose concentration through the activity of hexokinase in the range of 0.05 mM – 231 mM, encompassing glucose’s physiological range in blood. Localised and temporal enzyme kinetics of hexokinase was studied in detail. These results present a roadmap towards a viable personal metabolome machine
The prevalence of online health information seeking among patients in Scotland: a cross-sectional exploratory study
Background: Online health information seeking is an activity that needs to be explored in Scotland. While there are a growing number of studies that adopt a qualitative approach to this issue and attempt to understand the behaviors associated with online health information seeking, previous studies focusing on quantifying the prevalence and pattern of online health seeking in the United Kingdom have been based on Internet users in general.
Objective: This exploratory study sought to describe the prevalence of online health information seeking in a rural area of Scotland based on primary data from a patient population.
Methods: A survey design was employed utilizing self-completed questionnaires, based on the Pew Internet and American Life Project; questionnaires were distributed among adult patients in 10 primary care centers in a rural community in Scotland.
Results: A convenience sample of 571 (0.10% of the total population in Grampian, N=581,198) patients completed the questionnaire. A total of 68.4% (379/554) of patients had previously used the Internet to acquire health information. A total of 25.4% (136/536) of patients consulted the Internet for health information regarding their current appointment on the day surveyed; 34.6% (47/136) of these patients were influenced to attend their appointment as a result of that online health information. A total of 43.2% (207/479) of patients stated the health information helped improve their health and 67.1% (290/432) indicated that they had learned something new. A total of 34.0% (146/430) of patients talked to a health professional about the information they had found and 90.0% (376/418) reported that the information was useful. In total, 70.4% (145/206) of patients were concerned about obtaining health information online from reliable sources. A total of 67.1% (139/207) of patients were concerned that a health site may sell their personal information, yet only 6.7% (36/535) checked the privacy policy of the site visited. However, 27.9% (55/197) of patients were not concerned about their employer finding out what health sites they visited, whereas 37.5% (78/208) were concerned that others would find out.
Conclusions: The results suggest that online health information-seeking behavior influences offline health-related behavior among the population surveyed. Patient attitudes to online health information seeking were focused on issues relating to trust, reliability, privacy, and confidentiality. This study provides support for the growing phenomenon of an empowered, computer-literate, health information consumer, and the impact of this phenomenon must be considered in the context of the patient-health professional dynamic. The unpredictable nature of human thought and action in relation to this field of study requires an ongoing program of ethnographic research, both physical and virtual, within a Health Web Science framework. This study has provided a baseline of the prevalence of online health information seeking in the Grampian region of Scotland
A colorimetric CMOS-based platform for rapid total serum cholesterol quantification
Elevated cholesterol levels are associated with a greater risk of developing cardiovascular disease and other illnesses, making it a prime candidate for detection on a disposable biosensor for rapid point of care diagnostics. One of the methods to quantify cholesterol levels in human blood serum uses an optically mediated enzyme assay and a bench top spectrophotometer. The bulkiness and power hungry nature of the equipment limits its usage to laboratories. Here, we present a new disposable sensing platform that is based on a complementary metal oxide semiconductor process for total cholesterol quantification in pure blood serum. The platform that we implemented comprises readily mass-manufacturable components that exploit colorimetric changes of cholesterol oxidase and cholesterol esterase reactions. We have shown that our quantification results are comparable to that obtained by a bench top spectrophotometer. Using the implemented device, we have measured cholesterol concentration in human blood serum as low as 29 μM with a limit of detection at 13 μM, which is approximately 400 times lower than average physiological range, implying that our device also has the potential to be used for applications that require greater sensitivity
Disposable paper-on-CMOS platform for real-time simultaneous detection of metabolites
Objective: Early stage diagnosis of sepsis without overburdening health services is essential to improving patient outcomes. Methods: A fast and simple-to-use platform that combines an integrated circuit with paper microfluidics for simultaneous detection of multiple-metabolites appropriate for diagnostics was presented. Paper based sensors are a primary candidate for widespread deployment of diagnostic or test devices. However, the majority of devices today use a simple paper strip to detect a single marker using the reflectance of light. However, for many diseases such as sepsis, one biomarker is not sufficient to make a unique diagnosis. In this work multiple measurements are made on patterned paper simultaneously. Using laser ablation to fabricate microfluidic channels on paper provides a flexible and direct approach for mass manufacture of disposable paper strips. A reusable photodiode array on a complementary metal oxide semiconductor chip is used as the transducer. Results: The system measures changes in optical absorbance in the paper to achieve a cost-effective and easily implemented system that is capable of multiple simultaneous assays. Potential sepsis metabolite biomarkers glucose and lactate have been studied and quantified with the platform, achieving sensitivity within the physiological range in human serum. Conclusion: We have detailed a disposable paper-based CMOS photodiode sensor platform for real-time simultaneous detection of metabolites for diseases such as sepsis. Significance: A combination of a low-cost paper strip with microfluidic channels and a sensitive CMOS photodiode sensor array makes our platform a robust portable and inexpensive biosensing device for multiple diagnostic tests in many different applications
Accurate structure factors from pseudopotential methods
Highly accurate experimental structure factors of silicon are available in
the literature, and these provide the ideal test for any \emph{ab initio}
method for the construction of the all-electron charge density. In a recent
paper [J. R. Trail and D. M. Bird, Phys. Rev. B {\bf 60}, 7863 (1999)] a method
has been developed for obtaining an accurate all-electron charge density from a
first principles pseudopotential calculation by reconstructing the core region
of an atom of choice. Here this method is applied to bulk silicon, and
structure factors are derived and compared with experimental and Full-potential
Linear Augmented Plane Wave results (FLAPW). We also compare with the result of
assuming the core region is spherically symmetric, and with the result of
constructing a charge density from the pseudo-valence density + frozen core
electrons. Neither of these approximations provide accurate charge densities.
The aspherical reconstruction is found to be as accurate as FLAPW results, and
reproduces the residual error between the FLAPW and experimental results.Comment: 6 Pages, 3 figure
Difluorocarbene Generation from TMSCF3: Kinetics and Mechanism of NaI-Mediated and Si-Induced Anionic Chain Reactions
The mechanism of CF2 transfer from TMSCF3 ( 1 ), mediated by TBAT (2–12 mol %) or by NaI (5–20 mol %), has been investigated by in situ/stopped-flow 19F NMR spectroscopic analysis of the kinetics of alkene difluorocyclopropanation and competing TFE/c-C3F6/homologous perfluoroanion generation, 13C/2H KIEs, LFERs, CF2 transfer efficiency and selectivity, the effect of inhibitors, and density functional theory (DFT) calculations. The reactions evolve with profoundly different kinetics, undergoing autoinhibition (TBAT) or quasi-stochastic autoacceleration (NaI) and cogenerating perfluoroalkene side products. An overarching mechanism involving direct and indirect fluoride transfer from a CF3 anionoid to TMSCF3 ( 1 ) has been elucidated. It allows rationalization of why the NaI-mediated process is more effective for less-reactive alkenes and alkynes, why a large excess of TMSCF3 ( 1 ) is required in all cases, and why slow-addition protocols can be of benefit. Issues relating to exothermicity, toxicity, and scale-up are also noted.PostprintPeer reviewe
Capsule endoscopy compatible fluorescence imager demonstrated using bowel cancer tumours
We demonstrate a proof of concept highly miniaturised fluorescence imager and its application to detecting cancer in resected human colon cancer tissues. Fluorescence imaging modalities have already been successfully implemented in traditional endoscopy. However, the procedure still causes discomfort and requires sedation. Wireless fluorescence capsule endoscopy has the potential to improve diagnostic accuracy with less inconvenience for patients. In this paper we present a 5 mm x 6 mm x 5 mm optical block that is small enough to integrate into a capsule endoscope. The block integrates ultrathin filters for optical isolation and was successfully integrated with a sensitive CMOS SPAD array to detect green fluorescence from Flavin Adenine Dinucleotide (FAD), which is an endogenous fluorophore responsible for autofluorescence in human tissues, and fluorescence from the cancer selective molecular probe ProteoGREENTM-gGlu used to label colorectal cancer cells. In vitro studies were validated using a commercial ModulusTM Microplate reader. The potential use of the device in capsule endoscopy was further validated by imaging healthy and malignant resected human tissues from the colon to detect changes in autofluorescence signal that are crucial for cancer diagnosis
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